Dutch Town Lays Air-Purifying Concrete

eldavojohn writes "In an effort to combat air pollution, a Dutch town has paved some of its streets with air-purifying concrete. It contains a titanium dioxide-based additive that utilizes sunlight to turn car exhaust into harmless nitrates. It was shown to do this in a lab and now the scientists are interested in just how much this will affect the air quality around the road. They will sample the air quality by a normal road and by this newly paved one."

Comments

Offset?

[Recovering Hater]

Because the purifying concrete offsets the pollution incurred from mining the titanium to create the concrete? Am I wrong in thinking I knew an old lady who swallowed a fly? Someone weigh in on this please. Thanks :P

Re:Offset?

[Anonymous Coward]

This one is obviously about enhancing the air in the city. It is not supposed to solve any large scale problems with the climate. Didn't RTFA.

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[hardburn]

It might. If it works well enough, it would mean we could either remove catalytic converters from cars (which would increase engine efficiency), or promote the use of small diesels (which can be more fuel efficient but release a lot more NOx), and end up with a net win for smog pollution.

In other words, it doesn't directly do anything greenhouse gases, but it does allow us to produce less greenhouse gases by using techniques that produce more nitrates.

Re:Offset?

[rjhubs]

I supposed it could work because the cost of getting titanium is a one time cost, but the effects of the concrete will continue working over time.

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[SirCowMan]

It reduces smog more than prevents global warming (NOx's vs. apmospheric carbon), I do believe :)

Re:Offset?

[Born2bwire]

It would depend on whether or not the titanium dioxide is acting as a catalyst or component of the reaction.

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[FireStormZ]

The Titanium is not consumed in this process (merely a catalyst) so it might very well be worth it in the long run..

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[plague3106]

So are you advocating that we just all kill ourselves? Or go back to sleeping under trees? Because once we start building anything, we create some kind of pollution.

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[baldass_newbie]

You should have. They're only paving one side of the street with it. This way they can test the air quality on either side of the street and see if there's any difference.
It's an experiment.
Couldn't see anyone doing 'testing' in a town in the US without two very big teams of lawyers being involved.
Yeah innovation!

Re:Offset?

[mrchaotica]

Actually, there's a recurring cost for the concrete as well: it doesn't last forever, you know! It lasts longer than asphalt concrete, but it'll still need to be repaved after a few decades.

(At least, it doesn't last forever the way we use it -- if we built like the Romans did, it'd last forever but cost a heck of a lot more.)

Re:Offset?

[Anonymous Coward]

"Recovering Hater"

I think you'd find an objection, no matter how ridiculous, just because you want to demonstrate that you're smart enough to find an objection.

PS, if you're truly "recovering" then your post was a serious relapse.

Re:Offset?

[MillionthMonkey]

If it works well enough, it would mean we could either remove catalytic converters from cars (which would increase engine efficiency), or promote the use of small diesels (which can be more fuel efficient but release a lot more NOx), and end up with a net win for smog pollution.

An exhaust-eating road surface is never going to be as efficient as a guy just chasing your car down the street with a big vacuum cleaner hose. I think we're keeping our catalytic converters.

Re:Offset?

[Anonymous Coward]

There are many things that can be simply picked up off the ground and used in building. For building huts (grasses, fallen branches, rocks for hammers). These don't create any pollution. Even using wood in general doesn't really create pollution (i.e. The tree will die eventually, so no extra pollution is created and nature is designed to handle that type of pollution), especially if it is all chopped up with hand-axes and tied with plant parts gathered by hand. People have always had at least some things that we build that don't produce pollution.

Re:Offset?

[Anonymous Coward]

How, exactly, is removing the catalytic converter (which acts on the engine's exhaust just before it is expelled to the atmosphere) supposed to help improve engine efficiency?

Do you realize what you just said is the equivalent of claiming that a new computer monitor will give you better CPU performance?

Re:Offset?

[Maint_Pgmr_3]

that utilizes sunlight to turn car exhaust into harmless nitrates.

How much money is spent going around in circles? catalytic converters convert nitrates to harmless substances, then the road makes them more harmless?
where is AlGore when we need him??

Re:Offset?

[Anonymous Coward]

How, exactly, is removing the catalytic converter (which acts on the engine's exhaust just before it is expelled to the atmosphere) supposed to help improve engine efficiency? Do you realize what you just said is the equivalent of claiming that a new computer monitor will give you better CPU performance?

Because it's a flow restriction and the engine has to work to pump through it. In fact, particulate filters and catalytic converters and mufflers on new US diesel trucks harm the efficiency so much that it can do as much as 4 mpg damage.

Re:Offset?

[Anpheus]

The catalytic converter isn't as efficient as a straight pipe. While not legal, cutouts that push exhaust straight outside the engine and bypass the exhaust system do improve horsepower.

It's more like bumping up the speed of your front side bus on your CPU. If you have a slower FSB, you might not ever notice it if you aren't racing your ca... CPU. But when you need that speed, it sure would be nice to remove the FSB limitation.

That said, the amount of good that catalytic converters do means we should probably keep them, as they aren't a huge drain on the power of a vehicle.

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[KGIII]

Al? He's putting on his wizard hat and robe. He'll be unavailable for a while.

Re:Offset?

[Anonymous Coward]

An exhaust-eating road surface is never going to be as efficient as a guy just chasing your car down the street with a big vacuum cleaner hose. I think we're keeping our catalytic converters.

I am interested in your technology. Where may I sign up for your newsletter?

Re:Offset?

[Anonymous Coward]

That isn't true at all.

I'm no engine expert, but I think catalytic converters typically introduce additional restriction to an exhaust system. This will often reduce power output, the net result of which is the use of slightly more gasoline to do the same work.

The trade off with catalytic converters is not a new one, here is a post from the NY Times in 1998 that talks about it: http://www.sepp.org/Archive/controv/controversies/catalytic.html

Re:Offset?

[Anonymous Coward]

I believe most (almost all?) concrete is recycled into... new concrete so the titanium oxide would be recycled as well?

Re:Offset?

[Anonymous Coward]

Actually it's pretty common knowledge among car buffs that running a more open exhaust will give you more power. (It's more technical than that and there is an optimum amount of back pressure that you want, but getting rid of your stock catalytic converter will definitely make it more efficient) Example -
http://www.popularhotrodding.com/enginemasters/articles/hardcore/0505em_exh/index1.html

Re:Offset?

[Anonymous Coward]

Of course, this logic holds that all existing paved roads must be replaced with roads bearing this new concrete surface. Relatively speaking, it would probably be cheaper to simply replace all rolling stock with equivalent H2 power. Consider that MOST of the roads, at least those in my area, are NOT concrete to begin with, so this program would require that the preexisting asfault bed must be dug up, disposed of and then replaced with this new titanium catalyst concrete.

Re:Offset?

[Anonymous Coward]

A proof of concept/prototype will always cost more in resources and pollution and what-not than it is worth by itself. But, if it is proven to work, then I suppose the idea would be to expand the project such that economies of scale for both cost and pollution kick in...
At least that's how it makes sense to me, your local AC.

Re:Offset?

[sglewis100]

Remind me not to visit your hous... i mean hut. If the only way to build housing without creating pollution is to live in a hut, then no thanks, I'll take a little pollution and go back to my house.

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[lukas84]

Bonus points for using an IT analogy in a car discussion ;)

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[hardburn]

Also, cats force you to run the engine at the stoichiometric point, which isn't the best way to run under all conditions. Direct injection can mitigate this problem, though.

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[e4g4]

How, exactly, is removing the catalytic converter (which acts on the engine's exhaust just before it is expelled to the atmosphere) supposed to help improve engine efficiency?

The same way removing your muffler does - both the muffler and the catalytic converter restrict the flow of exhaust in the car (thereby restricting the intake, and subsequently reducing the amount of power the car can generate). NASCAR teams remove the mufflers and catalytic converters from cars - adding about 50HP to the car in the process.

Re:Offset?

[Bruiser80]

Titanium Dioxide is not a rare compound, just like Aluminum Dioxide isn't. Pure Aluminum or Titanium are rare.

The original Crown Jewels contained Aluminum because it was a precious metal at the time. A chemical process was developed by Reynold around the 19th/20th century to convert a lot of Aluminum Dioxide into pure Aluminum using a small amount of pure Aluminum.

Re:Offset?

[infolib]

the pollution incurred from mining the titanium

This is not titanium, it's titanium dioxide which can be mined from the ground in some places. Wikipedia says that "The relatively high market value of titanium is mainly due to its processing" from oxide. Besides that, it's only needed in the surface, no need to fill the whole concret slab, just the layer that'll wear.

Re:Offset?

[howdoesth]

It's more like bumping up the speed of your front side bus on your CPU. If you have a slower FSB, you might not ever notice it if you aren't racing your ca... CPU. But when you need that speed, it sure would be nice to remove the FSB limitation.

Did you just use a computer analogy to explain a car problem?

Re:Offset?

[dgatwood]

Aha! The foot is on the other shoe now!

Wait... what?

:-D

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[bob_herrick]

RTFS. It works in combination of sunlight. You would have to reinstall the cc at dusk, and during winter months and bad weather. That seems unlikely to me.

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[nospam007]

It's a very green technology because the bricks they use to do this are actually...green.

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[quadrox]

Someone I know even believes that removing the catalytic converters on modern cars will reduce exhaust particles since they will run more efficient and thus output less particles in the first place. Can anyone confirm or deny this in a credible fashion?

Re:Offset?

[DigiShaman]

While not legal, cutouts that push exhaust straight outside the engine and bypass the exhaust system do improve horsepower.

Not necessarily.

While you will get more torque at the low-end of the RPM range, you might actually be losing overall HP. By having a proper diameter and length of pipe, you can take advantage of the "exhaust savaging" effect.

BTW, my 99 Miata is properly tuned with the right exhaust system.

Re:Offset?

[WebCowboy]

Am I wrong in thinking I knew an old lady who swallowed a fly? Someone weigh in on this please.

No you're quite right, but not quite for the same reason. Concrete and asphalt already used in the roads are the result of intensive mining, drilling and refining processes already, and titanium can be recoverer/reused, so I'd venture to say that though there would be an added environmental impact to include this "air scrubber" additive that it isn't the biggest factor offseting the benefits to air quality.

I'd say a more immediate concern is that this doesn't reduce pollution--it only converts it into anouther type of pollution. Smog-causing Nitrous oxides are certainly bad for our health, but nitrates are far from "harmless". I'd like to know what is done with the nitrates. Can they be recovered and used in a more controlled way (to fertilise crops and what not) or are they just left to be absorbed by the environment (dissolved in runoff, etc)?

Though proper amounts of nitrates are natural and beneficial in ecosystems, excess nitrates in the environment can destroy wetlands and other bodies of water by causing excess algae growth. Nitrates are also bad for animal life, from fish and amphibians to livestock. Nitrates can infiltrate well-basede drinking water supplies as well, creating health problems in people ranging from thyroid problems and vitamin deficiencies to low birth weights.

If there is some way to contain the nitrates as well as enjoy less smog I'd say it is promising, but we still have to work on more efficiently using fuels and not driving personal vehicles as much when there isn't a need to.

Re:Offset?

[paanta]

Government agencies like the DOT does testing all the time. Ever pass a sign on the highway saying you're going to be on experimental pavement for the next 500'?

Re:Offset?

[DerekLyons]

The Titanium is not consumed in this process (merely a catalyst) so it might very well be worth it in the long run..

Assuming the catalyst isn't poisoned by reaction byproducts, or removed by weathering, or sealed under oil etc., or otherwise rendered inactive by environmental effects.

Re:Offset?

[Amouth]

no but i do see signs every day that read "DOT road sign test in progress" - it is there everyday.. for about 4 years now... wonder if i should give them acall and see how the test is going

Re:Offset?

[PachmanP]

I thought it was the other way around. I thought you can't run at the stoichiometric point because the exhaust gets too hot and melts the cat.

Re:Offset?

[DeadDecoy]

Maybe that depends on where you put the concrete? Also, I'm sure you could place the road and keep your catalytic converters. That way you have cleaner air in particularly busy city environments like, say LA or New York.

Re:Offset?

[almightynayr]

I dont have a catalytic converter in my highly modified performance vehicle.. Passes emissions just fine without it, I am however injecting a mixture of water and methanol into my intake to increase the effective octane rating of pump gas, the methanol does do a little to scrub some of the nox emissions. However I am outputting almost 4x the original power, as a result I am using alot more fuel and outputting alot more exhaust so its not really all that efficient.. but it sure is fun to drive.

Re:Offset?

[Anonymous Coward]

"An exhaust-eating road surface is never going to be as efficient as a guy just chasing your car down the street with a big vacuum cleaner hose."

I dunno, that seems pretty energy-inefficient to me. Unless he was on a segway...

Re:Offset?

[eugene ts wong]

Maybe somebody can be given a contract to collect the nitrates, and purify it for garden use. Does anybody know how expensive it is to produce nitrate for a garden fertilizer?

Re:Offset?

[dmsuperman]

The problem is that with more traffic you get degrading roads faster, meaning more mining is required. The numbers and particulars are certainly important in this equation, because there's far too much to just guess at.

Re:Offset?

[sumdumass]

He is off warning people about ManBearPig. Some things are just more important then fixing fixed fixes.

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[Chosen Reject]

excess nitrates in the environment can destroy wetlands and other bodies of water by causing excess algae growth.

I'm going out on a limb here to talk about something I haven't a clue about, but it appears the problem with nitrates (nitrogen?) causing problems with algae has been debunked.

From the article linked:

That might have been the end of the debate. But over the years, the idea that nitrogen removal is needed to control the chemical buildup that causes algae blooms know as "eutrophication" has persisted.

Schindler's latest series of long-term experiments shows that nitrogen removal completely fails to control blue-green algae blooms. He proved this by manipulating nitrogen and phosphorus levels on Lake 227 for 37 years. Nitrogen control, he found, only encouraged algae blooms.

Granted, that only deals with one of the downsides of nitrates you mention. Admittedly, I don't know enough about it, so maybe nitrates and nitrogen are different and so I'm just talking out of my rear.

Re:Offset?

[plague3106]

That was exactly my point... that almost anything we do will cause pollution, so the arguement that mining causes pollution is kinda moot.

Re:Offset?

[statemachine]

I'm going out on a limb here to talk about something I haven't a clue about, but it appears the problem with nitrates (nitrogen?) causing problems with algae has been debunked.

You forgot to include:

Punchline: "Phosphorus."

It's fairly recent research, so I don't blame people's ignorance. Although, dumping nitrates in the water should still be avoided.

Re:Offset?

[BrainInAJar]

And burning oil doesn't create pollution either because that carbon all used to be in the air anyways, it was just fixed by living things, so clearly the planet evolved ( it wasn't designed ) to handle that too

Re:Offset?

[hardburn]

From Wiki:

These three reactions occur most efficiently when the catalytic converter receives exhaust from an engine running slightly above the stoichiometric point. This is between 14.8 and 14.9 parts air to 1 part fuel, by weight, for gasoline (the ratio for LPG, natural gas and ethanol fuels is slightly different, requiring modified fuel system settings when using those fuels). When there is more oxygen than required, then the system is said to be running lean, and the system is in oxidizing condition. In that case, the converter's two oxidizing reactions (oxidation of CO and hydrocarbons) are favoured, at the expense of the reducing reaction. When there is excessive fuel, then the engine is running rich. The reduction of NOx is favoured, at the expense of CO and HC oxidation. If an engine could be operated with infinitesimally small oscillations[citation needed] about the stoichiometric point for the fuel used, it is theoretically possible to reach 100% conversion efficiencies.

Re:Offset?

[Oktober Sunset]

My asplode just headed.

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[BattleApple]

I say just have everyone hang a brick off their bumper directly behind the tailpipe

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[Anonymous Coward]

wrong;

you will do work to build your house (no matter what you use.)

As your body expends energy, you will exhale CO2.

Depending on your diet and state of digestion, you may also kick a little methane out the "back end."

Thus, you have damaged your world by building your little hut.

sniff.

Re:Offset?

[Plutonite]

No. Where is this magnificent part of the US, of which you speak, and do you have women over there?

Over here (in North California, no less) I try to avoid the highway when possible because the smaller roads are nicer. Welcome to America. I wish they would experiment with them, I really do.

Re:Offset?

[today]

There is indeed an efficiency cost to smog reduction devices. An engine running at best efficiency will probably put out too much NOx, which is the nastiest of smog products. Think LA air, 1970s, or Bejing, 2008.

Re:Offset?

[today]

Just because you pass static emissions tests does not mean your car would pass a full-dyno emission test like they do when the car is under development. The bi-annual test usually only tests the car at a couple of load points, and they assume if it passes those, it is in working condition. You car should not pass a California inspection because they are supposed to check that the CAT actually exists (unless you've simply cored it out or welded a CAT shell around the exhaust pipe to fake it).

My guess since you are tuned for performance is that you are emitting a lot more HC and CO than you would be if you had a CAT installed.

Re:Offset?

[32771]

This kind of thinking turns up way too often. The titanium oxide exists in nature as such and as a catalyst remains unchanged for ever. You can't beat that.

The same silly thinking comes up with power plants. Oh but it takes a lot of energy to mine such and such. BS! You can read:

http://www.amazon.com/Food-Energy-Society-David-Pimentel/dp/0870813862

They have nice tables on how much energy you invest into most technologies to get another amount of energy out, and guess what you always get more out. Just some look worse than others like biofuels and nuclear energy (sniff, my nuclear fanboyism just got demolished)

Just as a side note if you can't quantify your gut feel read up on it and prevent yourself from sounding silly.

Re:Offset?

[32771]

So and what are you doing about a bunch of drunk guys peeing into the corners? Certainly we would have to do a study who adds more nitrogen to the environment.

Re:Offset?

[homer_ca]

You're right about the exhaust scavenging effect. Simply reducing exhaust backpressure while doing nothing else to the engine yields poor results. Other engine parameters like intake length, valve timing, ignition timing, etc. etc. all need to be tuned together. Yamaha motorcycles have a throttle valve in the exhaust called EXUP. It actually increases backpressure at low rpm to improve torque.

The big reason catalytic converters got a bad rep early on is because of compression ratio. High compression is good for both power and efficiency, but high compression engines also need high octane gas to prevent knocking. Lead was used as a cheap octane booster, but it'll destroy catalytic converters. In the early days unleaded gas was only available in low octane, and cars with catalytic converters came with weak low compression engines.

Re:Offset?

[Anonymous Coward]

Maybe they could plant a tree. Or many trees. Just an idea.

Re:Offset?

[Anonymous Coward]

i would have to imagine though that the surface would have to be kept clean in order to function properly. any oil or dirt on the surface is going to clog up the catalyst, thereby reducing overall efficiency.

Re:Offset?

[MrKaos]

They're only paving one side of the street with it. This way they can test the air quality on either side of the street and see if there's any difference.

Now we know why the chicken crossed the road!

bad-duum-tish!!!

Re:Offset?

[shawb]

Eh... Nitrates have been found to be not that big of a deal, really. There are bacteria that convert nitrates into nitrogen gas, somewhat regulating the levels (although these can be overrun by massive dumping.) Experiments show time and time again that what really gets aquatic and semi-aquatic environments is the phosphates. There really isn't a natural mechanism for pumping that phosphorous out.

Re:Offset?

[Anonymous Coward]

True. If only there were some way to determine whether this technology can work in the real world... some sort of test perhaps...

Re:Offset?

[dbIII]

It is sand seperated out from the other kinds of sand by gravity.

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[gregbot9000]

Smell that? I better go scrub my road.

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[glittalogik]

We're off to see the Wizard! The wonderful Wizard of-...wait, where the hell are we?

Re:Offset?

[Tsen]

When I visited North Carolina last month, your highways rocked. Lots of plants and flowers lining the whole road, trees so thick you can't see buildings on either side...Here in Utah you're lucky if sagebrush is growing by the highway.

Re:Offset?

[codeButcher]

I'm not a chemist, but I understand that unleaded gasoline contains additives that are even more harmful to human health than the lead-based additives in leaded gas. Problem is that the lead "poisons"/renders useless the catalytic converter, while the cat will break down the harmful substances in unleaded.

Or to put it in other words: unleaded with cat is better than leaded without cat, but unleaded without cat is worse than leaded without cat.

In my locale, "unleaded" often meant the addition of a manganese compound, which while not harming the cat chemically, over time does clog up the fine honeycomb structure physically, rendering the thing useless. A well-known german marque (a three letter acronym) of luxury vehicles did some tests locally which brought this to light (not that anything was done about it).

Many vehicles are in a bad state of repair, due to the financial burden, and I can't see many vehicle owners replacing the (very expensive) cat if it gets clogged up or physically damaged. (Vehicles are also driven for longer before being replaced than in the Western countries in which they where designed.) Even the mentioned TLA marque unofficially will insert a normal section of pipe into the gap in your exhaust system once the cat comes out after 5 years or so.

So much for good intentions.....

Re:Offset?

[Candid88]

"Do you realize what you just said is the equivalent of claiming that a new computer monitor will give you better CPU performance?"

This is why analogies are so awful and destructive to rational discussion.

On the face of it this analogy seems apt despite the fact that - as other replies point out- it's actually completely incorrect.

In this case we're talking about technical facts so it's possible to decisvely prove the analogy is wrong, but in most areas of life (particularly things like politics & sociology) it can be nigh on impossible to judge an analogy's true validty so if it sounds O.K. (as the above one does) then most people may believe it whether it's right or wrong.

A politicians dream, but like I said, terrible for rational discussion.

Re:Offset?

[bibi-pov]

Problem is 4mpg doesn't mean much. Is that 4mpg starting from 15 mpg (26%) or 4 mpg starting from 45mpg (8.9%). mpg gains diminishe as you go higher and higher, meaning that going from 15 to 17 (+11% efficiency) mpg yields a greater gain in efficiency than going from 45 to 49mpg (2x the mpg, but only a 8% gain in efficiency).

Re:Offset?

[PingPongBoy]

Couldn't see anyone doing 'testing' in a town in the US without two very big teams of lawyers being involved

The lungs purify the air. Presumably, hHaving teams of lawyers in your neighborhood would purify the air there a little. So you can have an experiment in such a way.

Re:Offset?

[Frank T. Lofaro Jr.]

Doesn't matter as much for cars, since there usually is a big flow restriction at the throttle (*), unlike diesels which lack one.

* although in Las Vegas, it seems a lot of people are driving with their foot to the floor, which eliminates that issue. ;)

Re:Offset?

[almightynayr]

I pass a rolling dyno emissions test, and I would pass in California because I have a shell welded arround my straight pipe. There are plenty of other reasons why California might not let me tag in there state but emissions is not one of em. I dont even have a check engine light.

Re:Offset?

[bandmassa]

Am I wrong in thinking I knew an old lady who swallowed a fly? Someone weigh in on this please. Thanks :P

Don't know, you're the one who is claiming to have known her ;-)

Re:Offset?

[kesuki]

"or promote the use of small diesels (which can run on bio-diesel 99% using 1% diesel to prevent fungal growth (it's that toxic) and release almost no harmful emissions, except a slight burned grease smell)"

There fixed that for you. and if we use algae to produce all that diesel, we can simultaneously use up a lot of waste water processing requirements (algae loves human sewage) as well as have a totally local, totally green energy source. as well as have a huge source of starch/dextrose for production of ethanol for those who want to run e-85.

the downside of bio-diesel production is it totally killed the glycerol market. but new ways of using glycerol, and new methods for using glycerol from bio-diesel show a promising chemical market for the future of 'green' energy companies. http://www.treehugger.com/files/2008/07/biodiesel-bypoduct-could-yield-valuable-chemicals.php

frankly I think that using a product so toxic that using just 1% of it is enough to prevent fungal growth, as a combustible fuel is awful, no matter what price has been paid in the past. Diesel fuel hasn't gone down in price even with the price of oil going down either. this makes clean mass producible algae based bio-diesel even more attractive. it certainly hasn't made soy-diesel any more attractive, because soy uses more 'energy' in fertilizer, farm equipment, and transit fuel, as well as processing cost. algae needs water, which means in general it can be grown near aquifers, that means it can be shipped over water from growing to processing plants. this drops costs incredibly, because fuel per tonnage is so low over aquatic lanes.

Re:Offset?

[Anonymous Coward]

Not Kansas, obviously.

Back on topic, they seem to be trading air pollution for potentially more disastrous water pollution. I can hear it now, "We halted global warming, but our seas and oceans are all dead."

Re:Offset?

[emilper]

probably just painted the sidewalk with white paint ... titanium dioxide based, too ...

Rendering

[darkstar-x]

How bout rendering existing buildings?

Re:Rendering

[xerxesVII]

Rendering them... what exactly?

Or did you mean to suggest that buildings we can't see don't get rendered even though they exist?

TFA interesting but light on details

[dedazo]

All passive filters I know require replacement because they get clogged, or the active elements eventually decay. Beyond making jokes about swapping the church bricks five years from now, TFA was a bit light on the details. Does anyone know how does this works, from a chemical perspective?

Re:TFA interesting but light on details

[Rob T Firefly]

I'm also a bit curious about the "harmless nitrates" that will be washed into the ground every time it rains.

Re:TFA interesting but light on details

[Anonymous Coward]

I would imagine that active elements would decay, and that in a number of years, the concrete wouldn't do anything.

But by then, the road would need to be repaved anyways, so that's not really a problem. As long as it remains chemically active for a longer timespan than the life of the road, we're good.

Re:TFA interesting but light on details

[jason.sweet]

It's OK. The increase in hurricane activity due to global warming will offset the negative effects of the increased nitrates.

Re:TFA interesting but light on details

[Andy Dodd]

http://en.wikipedia.org/wiki/Photocatalysis
http://en.wikipedia.org/wiki/Titanium_dioxide

TiO2 can catalyze a wide variety of chemical reactions in the presence of ultraviolet light (such as sunlight).

Re:TFA interesting but light on details

[sm62704]

Illinois is a farm state, and I live right in the middle of it. You know what nitrates are used for here, don't you? I mean, besides explosives and methamphetamines?

I'm sure I get lungsfull all the time. Not that I'm happy about it.

Re:TFA interesting but light on details

[gnuman99]

Nitrate is also known as a fertilizer.

Maybe that will cause people to think twice before,

    1. laying down fertilizer on their lawn, and shipping cut grass to landfills - leaving grass where it is provides the new grass with its own fertilizer.

    2. writing that nitrates can be worse than NOx (NO, NO2 and others)

NO3 is completely harmless compared to the more volatile cousins NOx that come out of tail pipes.

http://en.wikipedia.org/wiki/NOx

Re:TFA interesting but light on details

[dedazo]

OK, that makes sense. Being originally from a third-world country the thought of repaving a road is alien to me... <g>

Re:TFA interesting but light on details

[tirerim]

Nitrates can still cause problems -- they're a serious source of water pollution, leading to algae blooms (which in turn lead to other problems) and possibly drinking water contamination. Fertilizer runoff is a big issue in agricultural areas. They may still be less harmful overall than NOx, but they're certainly not harmless, and since they affect different domains any comparison is difficult to evaluate.

Re:TFA interesting but light on details

[gnuman99]

Algae blooms is NOT from nitrogen! It is from phosphate! *Phosphate* runoff from agricultural lands and similar sources is the cause the algae blooms.

http://findarticles.com/p/articles/mi_m0NTB/is_8_41/ai_94333421

Get rid of phosphate sources, and you get rid of algae blooms.

You see there is already LOTS of nitrogen in the water. It is the not limiting factor for algae. The limiting factors are phosphate and iron.

Re:TFA interesting but light on details

[Anonymous Coward]

You need to be more specific. NO3 is relatively harmless in air chemistry when compared to the classical NOx. But, when you get into water/soil chemistry, you have a different situation

Yes, you're right. NO3 is a bioavailable macronutrient, also known as a "Fertilizer." That is the root of the problem in water/soil chemistry. It is a fertilizer that will get washed into surface waters during rain events, pushing surface waters down-gradient to become more eutrophic. Not as big of a problem if you have lots of rain, surface water and tons of aquatic plants, but in the arid southwest, this is already a problem (see the issues with the salton sea, surface water in the central valley in california, canyon lake in southern riverside county, california, various fish-kills around the state, etc - excessive Nitrates are bad for fisheries and ecological stability), and it's only getting worse.
 
Excessive nitrates in the groundwater can also lead to hemoglobinemia in infants, which can leads to death. Generally speaking, nothing in excess is harmless. This is, at best, a regional solution. It would require a lot of rain to wash the nitrates out of the groundwater and out of the surface water, into the ocean. And, even then, you still have the existing nutrient loading of estuaries that exists in just about every stream outlet that is downstream from an urban or agricultural area. Something like this would exacerbate that.
 
    In reality, you would probably have to route your run-off water through primary treatment to get all the floating crap out of it that is inherent to urban run-off, then route it through some kind of man-made marsh to pull the excess nitrogen out of it, then return it to your drainage system/discharge it into the ocean to minimize the impact of nutrient loading. If you want an actual solution, instead of a band-aid, we gotta ditch the internal combustion engine and move onto something better.

Re:TFA interesting but light on details

[Killjoy_NL]

Too bad (I think) that we don't get too many hurricanes in the Netherlands :)

Re:TFA interesting but light on details

[2marcus]

Ah, but NOx is converted to Nitrate in the atmosphere in the long run anyway, the titanium just speeds up the process. (where do you think acid rain comes from? NOx and SOx are precursors to acids, HNO3 and H2SO4)

.

So you'll get a localized increase of nitrates over the counterfactual, but regionally the nitrate level will remain the same. Also, I'm guessing that the amount of nitrate formed by this process will be much less than the nitrate we use in fertilizer, though I haven't looked up the numbers for that.

Re:TFA interesting but light on details

[ThatFunkyMunki]

Too bad titanium works as a catalyst in this reaction, meaning that no decay or loss in usability happens.

Harmless nitrates?

[Anonymous Coward]

Like what? Explosives or rocket fuel?

Nitrates are useful

[Plazmid]

Wonder if there is a way to harvest them from the street.

Interesting...

[Anonymous Coward]

If shown to have effective results in real world tests, this could be very good for our planet. At the rate we americas drive cars, this could help to go a long long long way in reducing our polution.

Re:Interesting...

[orclevegam]

Seems to be rather widespread usage already according to this wikipedia article.

Nitrates?

[ArcherB]

Nitrates? Aren't those bad in their own right? I'm thinking along the lines of fertilizer run-off and the affect it has on algae in oceans. Could this solution create worse problems?

Re:Nitrates?

[dAzED1]

I came in to comment on runoff into oceans as well. There's a huge area in the Gulf of Mexico that is dead - no oxygen, and thus no life, in the water. Now, I don't want to be so simple as to think all nitrates are created equal, but...

Re:Nitrates?

[jascha.cohen]

As i recall from my "environmental studies" class, it's not that nitrates are bad in-and-of-themselves, it's that when they accumulate in an area they can unbalance the system and create problems. Wikipedia has a decent article/overview on the topic. http://en.wikipedia.org/wiki/Nitrogen_cycle

Re:Nitrates?

[AKAImBatman]

Plants need Nitrates to grow. (Nitrates == Nitrogen based chemicals.) So it should actually be positive for the soil rather than negative. I stress *should* because without knowing the exact chemical composition, it's hard to understand if there are any hidden problems with this technique.

One thing I am worried about, though, is the color of these sidewalks. If they're using titanium dioxide, shouldn't they be a nice brown color? (Think: Coffee, cola, and other brown liquids.) I don't know about anyone else, but a brown sidewalk or street is not my idea of "attractive". (I presume the "green" bricks used in this trial have been painted or stained with an even more powerful pigment.) Of course, given the natural color of titanium dioxide, perhaps this technique is intended for use with blacktop rather than concrete as suggested by the article? In which case the brown would be unnoticeable. That would also jive with the replacement time for these roadways as any passive chemical solution is going to become less effective after a few years of use.

It would be nice if the article had more of these details.

Re:Nitrates?

[bcattwoo]

"One thing I am worried about, though, is the color of these sidewalks. If they're using titanium dioxide, shouldn't they be a nice brown color?"

Actually titanium dioxide is quite white. It is used as pigment for white base paint.

Re:Nitrates?

[AKAImBatman]

You're right. Thanks for pointing that out. I was confusing titanium dioxide with titanic acid. In which case, this compound should make for some rather gleaming streets! :-)

Re:Nitrates?

[hey!]

Anything is harmful in the wrong place and in the wrong concentrations. Nitrates are, for example harmful to fish in high concentrations.

Most systems have processes that are limited by the supply of some resource. Ocean ecosystems are nitrogen limited, whereas fresh water systems tend to be phosphorous limited. Thus if the nitrates are washed off into fresh water, they'll cause relatively little immediate damage unless the concentrations are high enough to be toxic. However, if that nitrate is carried downstream to the ocean, the plume of nitrogen rich water entering the ocean can cause blooms of organisms that use up so much oxygen that fin fish suffocate. This happens where the Mississippi enters the gulf.

So, how and where something like this is used makes a difference. If you imagine all the US cities along the Mississippi and its tributaries using it, and if there is a mechanism by which the nitrates make it into the rivers, then this could make the situation in the Gulf much worse. If you use it in a coastal city and only the runoff from that city affects the local ocean, the amount of nitrogen entering the ocean might or might not have any measurable effect.

Re:Nitrates?

[maxume]

Why do you think the sidewalks would be brown?

http://en.wikipedia.org/wiki/Titanium_dioxide

Re:Nitrates?

[SirMeliot]

At school many years ago we went to visit a plant that produced the stuff. Even the grass outside the building was covered in white.

Re:Nitrates?

[edittard]

The nitrates can't run off into the oceans, because Holland is below sea level.

Re:Nitrates?

[Anonymous Coward]

One thing I am worried about, though, is the color of these sidewalks. If they're using titanium dioxide, shouldn't they be a nice brown color?

They are going to balance it out with uranyl nitrate to give the sidewalks a bright yellow color.

Re:Nitrates?

[Hal_Porter]

Nitrates? Aren't those bad in their own right? I'm thinking along the lines of fertilizer run-off and the affect it has on algae in oceans. Could this solution create worse problems?

Well they make plants grow and that cuts down on the CO2.

Re:Nitrates?

[gnuman99]

AFAIK, also used in sunscreen.

http://en.wikipedia.org/wiki/Titanium_dioxide

And yes, it is white as seen in the above *picture* :)

Re:Nitrates?

[mrchaotica]

perhaps this technique is intended for use with blacktop rather than concrete as suggested by the article?

I would imagine it wouldn't work very well with asphalt concrete because the asphalt would coat the titanium particles and block the NOx from getting to them.

Re:Nitrates?

[bryce4president]

I knew somebody would say this... Its not the nitrates that do the harm, its the phosphates... Just a couple weeks ago this was reinforced... Source

Re:Nitrates?

[avandesande]

Nitrogon oxides eventually end up as nitrates, the TIO just speeds up the process.

Re:Nitrates?

[amper]

Yes, this is a problem. Take a look at any of the information available online about nutrient contamination of the Chesapeake Bay.

http://www.fws.gov/chesapeakebay/nutrient.htm

Re:Nitrates?

[clone53421]

Of
  course
  nitrates
  are
  harmless!

Re:Nitrates?

[bryce4president]

Oh come on. Really? Of course Nitrates are harmful, but maybe we should revisit the part where the Parent talks about Algae Blooms. Hmm, and then lets look at what I posted... Yeah, that referenced them as well...

I never said that nitrates are harmless, I said that it was phosphates causing the algae blooms.

Interestingly enough, not a single article you posted even has the word "algae" in it. But thanks for the off topic post anyway.

Re:Nitrates?

[Anonymous Coward]

Holland may well be underwater in 50 years.

Re:Nitrates?

[Anonymous Coward]

So the nitrates causes an explosion in algae. Algae, being a plant, creates oxygen. This leads to a lack of oxygen in the water -- how?

Re:Nitrates?

[JohnsonJohnson]

a) Not all of Holland is below sea level, 75% of it is above sea level.

b) Nitrates can still pollute the ground water then diffuse into the ocean and rivers

Re:Nitrates?

[clone53421]

He never said "algae blooms". He just said "the affect [sic] it has on algae". Furthermore, his final question was "Could this solution create worse problems?", and my answer was "Absolutely". I wasn't specifically referring to algae, perhaps, but I'm not offtopic: worse problems aren't restricted to algal blooms.

Anyway, wiki says you're wrong:

In most cases of excess nitrate concentrations in aquatic systems, the primary source is surface runoff from agricultural or landscaped areas which have received excess nitrate fertilizer. These levels of nitrate can also lead to algae blooms, and when nutrients become limiting (such as potassium, phosphate or nitrate) then eutrophication can occur.

Re:Nitrates?

[Krishnoid]

Well, at least they're cheaper than day rates.

-Theo, The Cosby Show (and others)

Re:Nitrates?

[clone53421]

Water can only hold a certain amount of oxygen. During the daytime, the water quickly becomes saturated with oxygen, but at night the oxygen is quickly depleted by the over-abundance of algae, resulting in oxygen deprivation and anaerobic conditions.

Re:Nitrates?

[bws111]

Wasn't it just shown that nitrates do not contribute to algae blooms, only phosphorus does?

Re:Nitrates?

[Sockatume]

Indeed, and I suspect the amount of nitrate produced would be pretty high. A quick google puts urban NOx production at the thousands of tonnes per day. Ignoring chemistry for the sake of simplicity, that'd equate to thousands of tonnes of nitrate being produced per day. If my maths is accurate. that's of the same order of magnitude as fertiliser nitrate runoff from the Mississippi to the Gulf of Mexico.

Re:Nitrates?

[TheLink]

The recent conclusion of a 37 year experiment is it's phosphorus not nitrogen that's the problem:

http://www.canada.com/victoriatimescolonist/news/story.html?id=381d4ce5-89a2-4901-864e-34239419bf67

Schindler's latest series of long-term experiments shows that nitrogen removal completely fails to control blue-green algae blooms. He proved this by manipulating nitrogen and phosphorus levels on Lake 227 for 37 years. Nitrogen control, he found, only encouraged algae blooms.

Re:Nitrates?

[bryce4president]

I'm thinking along the lines of fertilizer run-off and the affect it has on algae in oceans.

This is known as a description of the algae bloom problem. I know, you need to read between a line or two to understand what he was getting at, but I think you are capable.

Ah yes, lets quote wikipedia instead of actual research from the leading expert on the subject. Good one.

These levels of nitrate can also lead to algae blooms,

This is the EXACT misinformation my posted link is supposed to correct. Thanks for STILL being off topic AND producing bad sources.

Re:Nitrates?

[JoeMerchant]

If you like green grass growing beside your highway, nitrates are a good thing. Now, if the highway is a 10 lane bridge that drains directly into a shallow bay, then the nitrates might be a concern.

Re:Nitrates?

[ArcherB]

The recent conclusion of a 37 year experiment is it's phosphorus not nitrogen that's the problem:

http://www.canada.com/victoriatimescolonist/news/story.html?id=381d4ce5-89a2-4901-864e-34239419bf67

Schindler's latest series of long-term experiments shows that nitrogen removal completely fails to control blue-green algae blooms. He proved this by manipulating nitrogen and phosphorus levels on Lake 227 for 37 years. Nitrogen control, he found, only encouraged algae blooms.

That's what I was looking for... Thanx!

Re:Nitrates?

[clone53421]

Fine. I'll just repeat myself, too.

His final question was "Could this solution create worse problems?", and my answer was "Absolutely". I wasn't specifically referring to algae, perhaps, but I'm not offtopic: worse problems aren't restricted to algal blooms.

Re:Nitrates?

[bryce4president]

So we both agree that OTHER problems could arise or get worse, but algae blooms are NOT one of them. His question was in response to his previous sentence (more between the lines stuff). Just for the record.

Re:Nitrates?

[CodeMunch]

The less we pump/dump into our lakes/rivers, the better. However, it is phosphates that appear to be the culprit, not nitrates. Unfortunately I can't respond to all the "omfg nitrates" posts so since yours is the first I saw that specificially mentions the Nitrates I'll plunk this in here:

Recently on slashdot (July 22, 2008):

Scientists Solve Riddle of Toxic Algae Blooms http://news.slashdot.org/article.pl?sid=08/07/22/1546259

Link to TFA http://www.canada.com/victoriatimescolonist/news/story.html?id=381d4ce5-89a2-4901-864e-34239419bf67

In a famous 1974 aerial photograph published by the journal Science, two portions of their experimental Lake 226 were highlighted. One side was treated with carbon, nitrogen and phosphorous. The other was treated with just carbon and nitrogen.

The side receiving phosphorous rapidly developed a huge bloom of blue-green algae. The side not receiving phosphorous remained in near-pristine condition.

Re:Nitrates?

[Anonymous Coward]

Also Fudge Rounds

Re:Nitrates?

[caluml]

a) Not all of Holland is below sea level, 75% of it is above sea level.

Really? Cos that's a major reason why I wouldn't move there. Which big cities are below sea level then? I'll just avoid them.

Six amatuer comedians and 8 bottles of wine

Six amatuer comedians, 8 bottles of wine and one misspelling of amateur. :)

Re:Nitrates?

[Killjoy_NL]

We are actually doing quite fine.
The water is held back by the Deltawerken

http://en.wikipedia.org/wiki/Deltawerken

We are actively exporting this technology to other countries, china springs to mind, they had some water troubles a while back, evacuating a boatload of people. I live in the Netherlands, below sea level. Quite happily I might add :)

Re:Nitrates?

[NeutronCowboy]

Interestingly enough, his experiment confirms what is currently known - that too much phosphorus is bad for fresh water systems, and too much nitrogen is bad for salt water systems.

Re:Nitrates?

[smellotron]

Schindler's latest series of long-term experiments shows that nitrogen removal completely fails to control blue-green algae blooms. He proved this by manipulating nitrogen and phosphorus levels on Lake 227 for 37 years. Nitrogen control, he found, only encouraged algae blooms.

It took that much research to determine it? Man, there's gotta be thousands of individuals who have all seen this happen in their own homes. I have a freshwater planted tank. Fish waste produces large amounts of phosphorus and ammonia (which converts to nitrite, then nitrate). Infrequent water changes lead to algae blooms because the plants use all of the nitrogen up, and can't compete with algae for the phosphorus. In fact, most high-growth aquariums require nitrogen supplements.

Re:Nitrates?

[Anonymous Coward]

Parts of Holland may be below sea level, but:
1) This part is not: http://maps.google.nl/maps?f=q&hl=nl&geocode=&q=hengelo&ie=UTF8&t=h&z=12
2) Being below sea level never stopped us before from draining to the sea (we have known about pumps for quite some time now)

Re:Nitrates?

[codeButcher]

I hear that on average, the Dutch are the tallest people. Now we know why.

Re:Nitrates?

[Anonymous Coward]

c) We got pumps

Re:Nitrates?

[Errtu76]

I live near the largest 'robot' in the world, the Maeslantkering, also part of the Deltawerken: http://en.wikipedia.org/wiki/Maeslantkering

http://maps.google.nl/?ie=UTF8&ll=51.954211,4.166136&spn=0.02301,0.06403&t=h&z=14

Last summer they tested the 'arms'. Very impressive. Takes more than half an hour for it to be fully closed. Last year it was automatically activated for the first time since its creation. Yeah, i feel safe too :)

Re:Nitrates?

[edittard]

They're just like Germans, but without the sense of humor!

Re:Nitrates?

[Frank T. Lofaro Jr.]

Too bad we didn't use your technology in New Orleans.

Re:Nitrates?

[Killjoy_NL]

That was a damn tragedy which still makes me sad.

How green?

[Smivs]

This sounds like a great idea if it works, but surely producing concrete is a far from 'green' process. I wonder how long the concrete has to be in place to neutralise the polluting effect of manufacturing it in the first place.

Re:How green?

[ArcherB]

This sounds like a great idea if it works, but surely producing concrete is a far from 'green' process. I wonder how long the concrete has to be in place to neutralise the polluting effect of manufacturing it in the first place.

But we are producing concrete anyway, so we'll still be ahead as long as this process does not produce more pollution than the pollution from standard concrete + whatever it absorbs.

Re:How green?

[wizardforce]

as opposed to concrete that doesn't clean the air at all?

Re:How green?

[shaka999]

Minimizing total pollution is a great goal but for human habitation the location of the pollution matters as well. This would decrease pollution in cities where the concentration is the highest.

As others have said, we are making concrete anyways...

Re:How green?

[Blakey Rat]

What do you suggest paving the road with? Grass? Good intentions?

Re:How green?

[MightyYar]

Everyone knows that hubris is the best paving material, duh.

Re:How green?

[meldex]

"What do you suggest paving the road with? Grass? Good intentions?"

Well it worked for the road to hell, and I am told that road handles a lot of traffic.

Re:How green?

[Dirtside]

Harsh language?

Re:How green?

[smellotron]

I'm -1 on Good Intentions—poor traction on the winter.

Offset

[i_liek_turtles]

Well, it's not as though we don't already use titanium dioxide in toothpaste, paper, and paint... (slashdot not working right for me, so can't reply directly)

Re:Offset

[Anonymous Coward]

Toothpaste eh..?

So next time someone asks you why you're grinning, just tell him you're doing the environment a favor by converting NOx to nitrates on your teeth.

Offset may be ideal

[ArtemaOne]

I know nothing about this stuff, but wouldn't offset be ideal if nothing else? Areas immediately around roads are some of the worst air to breathe. I doubt this takes the asbestos from brakes out of the air though, so busy intersections will still be horrible. I wonder which is worse, a cooking fire inside a hut (black carbon) or a busy road?

Re:Offset may be ideal

[sm62704]

I doubt this takes the asbestos from brakes out of the air though

They haven't used asbestos in brake linings for a long time.

Re:Offset may be ideal

[AshtangiMan]

I have a few mechanic friends who still use the asbestos pads because they work better (according to them, this came up a couple of days ago at the coffee shop). So unless they are completely wrong, there is still asbestos in some brake pads.

Re:Offset may be ideal

[RingDev]

Your mechanic friends are idiots, IMO. Asbestos is organic, when you get it hot enough, like spirited road driving or light track time, it will out gas, and unless you have slotted/drilled rotors, you'll wind up with significantly less breaking power when you need it the most.

They would be much better off with a Carbonfiber/Semi-metallic (CM) pad. It will last longer, stop faster, not fade, and not pose any significant health risk to them, or people exposed to their break dust.

-Rick

Re:Offset may be ideal

[RingDev]

The ban on organic break pads and clutches was overturned. But since there have been a few high publicity cases in which asbestos manufacturers have been held liable for huge damages, most companies state side refuse to touch it.

Many high end imports still come with asbestos pads though, because even though they aren't as nice performance or health wise as the newer CM pads, they are extremely quiet. And you can still buy asbestos replacement pads for vehicles from the US, but it takes some digging.

I wouldn't trust them for any application that is being touted as needing 'better breaks' though. The CM pads are so much nicer if you're going to be putting the vehicle into any situation where break fade could be an issue.

-Rick

Re:Offset may be ideal

[AshtangiMan]

I said something similar to them, though not so incitefully as I have found that your approach tends to turn people off from what might be a good idea.

Re:Offset may be ideal

[clone53421]

WTF? Organic? Asbestos is no such thing. It's a mineral, and it's not carbon based. Maybe you're thinking of substitutes.

Re:Offset may be ideal

[clone53421]

Followup: Ok, a bit of research seems to indicate that some "organic" brake pads contain asbestos, but that still doesn't mean asbestos is organic. It isn't.

Re:Offset may be ideal

[RingDev]

You are correct, I brain farted while typing that. It should have said:

Asbestos is like organics, when you get it hot enough ... it will out gas

-Rick

Re:Offset may be ideal

[Anonymous Coward]

Well, not in Europe....

Exact location

[oever]

The road is here according to a Dutch source.

Re:Exact location

[dtml-try MyNick]

Ironic.
I live in, according to various sources, the most air polluted area of the Netherlands. The whole neighborhood is undergoing re-pavement as we speak. And where do they place these tiles?
Right.. in one of the more greener cities of the country.
Seems to me it should have been a no-brainer to where to test these tiles.

Side effects

[StreetStealth]

Is industrial development and research at a point now where we don't have to worry about suddenly discovering an airborne carcinogenic byproduct from the reaction in about 10 years?

If this is both safe and effective, it's a major breakthrough.

The results are in

[Anonymous Coward]

The scientists driving around to check their air sampling monitors negates any positive effect produced by the concrete.

Human Problems?

[strimpster]

After reading the article, it appears that the nitrates just run off after a rain. Where do they go to? local bodies of water. Reading the Wikipedia article for nitrates, there are negatives from exposure to nitrates in drinking water, especially for infants. I'm not sure how much is too much, or how much this method produces, but it may be cause for concern. Also, depending on how much this produces, there may be an increase in algae blooms.

Re:Human Problems?

[MightyYar]

Even if the nitrates DO wash into the local drinking water and there is a demonstrably bad effect, it still might be a good idea; the health effects of breathing smog might still be worse.

Re:Human Problems?

[AshtangiMan]

1. Pave road with this stuff.
2. Drive diesel cars on roads.
3. Nitrates -> algae blooms in marshes just off road sids.
4. Harvest algae and press to make bio-diesel.
5. Profit.

Re:Human Problems?

[amnezick]

3.5 ??? (algae in waterless environment?)

Re:Human Problems?

[Anonymous Coward]

from GGP:
Where do [nitrates] go to? local bodies of water.
from GP:
3. Nitrates -> algae blooms in marshes just off road sids [sic].

and then . . .
3.5 ??? (algae in waterless environment?)

Add the fact that this is a discussion about the Netherlands. Now parent poster, please tell us all about how you read things before you post. Or perhaps in the future you should post anonymously.

Too bad...

[Anonymous Coward]

...because concrete is one of the major sources of anthropogenic carbon dioxide.

Re:Too bad...

[Anonymous Coward]

Cement certainly is. But by volume concrete is very low (at 4% cement). So please to stick your head back in your anus.

harmless nitrates ?

[cinnamon colbert]

not to mention all the side products that are produced, msot of which i am willing to bet havenot even been identified, much less studied

J Environ Qual. 2008 Feb 11;37(2):291-5. Print 2008 Mar-Apr.Click here to read Links
        When does nitrate become a risk for humans?
        Powlson DS, Addiscott TM, Benjamin N, Cassman KG, de Kok TM, van Grinsven H, L'Hirondel JL, Avery AA, van Kessel C.

        Soil Science Dep, Rothamsted Research, Harpenden, Herts, UK.

        Is nitrate harmful to humans? Are the current limits for nitrate concentration in drinking water justified by science? There is substantial disagreement among scientists over the interpretation of evidence on the issue. There are two main health issues: the linkage between nitrate and (i) infant methaemoglobinaemia, also known as blue baby syndrome, and (ii) cancers of the digestive tract. The evidence for nitrate as a cause of these serious diseases remains controversial. On one hand there is evidence that shows there is no clear association between nitrate in drinking water and the two main health issues with which it has been linked, and there is even evidence emerging of a possible benefit of nitrate in cardiovascular health. There is also evidence of nitrate intake giving protection against infections such as gastroenteritis. Some scientists suggest that there is sufficient evidence for increasing the permitted concentration of nitrate in drinking water without increasing risks to human health. However, subgroups within a population may be more susceptible than others to the adverse health effects of nitrate. Moreover, individuals with increased rates of endogenous formation of carcinogenic N-nitroso compounds are likely to be susceptible to the development of cancers in the digestive system. Given the lack of consensus, there is an urgent need for a comprehensive, independent study to determine whether the current nitrate limit for drinking water is scientifically justified or whether it could safely

Re:harmless nitrates ?

[smellsofbikes]

>Moreover, individuals with increased rates of endogenous formation of carcinogenic N-nitroso compounds are likely to be susceptible to the development of cancers in the digestive system.

My memory of organic chemistry is that consumption of nitrites, not nitrates, results in formation of endogenous N-nitroso compounds, but I may be wrong.

Re:harmless nitrates ?

[Rakshasa Taisab]

Well, you'd rather have it in the air?

Re:harmless nitrates ?

[Anonymous Coward]

N0x from the exhaust ends up being oxidized eventually: the sooner the better, if you can't avoid producing it.

Whether NOx is oxidized on the road, or in a puddle or in a raindrop seems to make little difference to drinking water nitrate concentrations: it all ends up in the same water supply.

Sure, we should be aware that everything, at the right concentrations is toxic to humans, but that's irrelevant here, because the blue babies who lick this concrete have bigger problems.

Two problems

[snarfies]

1) From TFA: "'With one rain shower everything is washed clean,' the institution said in a statement." Ah, but exactly WHAT is washed to WHERE, eh? Are we just trading off air pollution for water pollution?

2) How durable is this new substance? How much pollution can the road suck up before it wears out? Will it need to be resurfaced and/or replaced every year? Two years?

Re:Two problems

[phorm]

Sounds to me like the nitrates will accumulate and then be washed away. They in themselves might not be so beneficial in concentrated form, but perhaps if they installed gutters the nitrates could then be used elsewhere. In many cases I believe that nitrates etc are beneficial for enriching plant soil, etc, we just don't want it creating massive amounts of unpleasant algae in the local watersheds.

Re:Two problems

[MightyYar]

we just don't want it creating massive amounts of unpleasant algae in the local watersheds.

"From Smog to the Bog"

Re:Two problems

[Anonymous Coward]

2) How durable is this new substance? How much pollution can the road suck up before it wears out? Will it need to be resurfaced and/or replaced every year? Two years?

The road surface is probably acting as a catalyst, so it shouldn't wear out chemically. With cars driving over it, that's another story.

Re:Two problems

[Greenmoon]

How durable is this new substance? How much pollution can the road suck up before it wears out? ...

I don't think that it sucks up anything. I think the material acts as a catalyst, not a sponge.

Re:Two problems

[Atari400]

1) From TFA: "'With one rain shower everything is washed clean,' the institution said in a statement." Ah, but exactly WHAT is washed to WHERE, eh? Are we just trading off air pollution for water pollution?

You mean air pollution that we don't have too much choice about breathing in, versus water pollution that can be filtered out?

2) How durable is this new substance? How much pollution can the road suck up before it wears out? Will it need to be resurfaced and/or replaced every year? Two years?

As I understand it TiO2 is acting as a catalyst, so it shouldn't need replacing. However, as a resident of The Netherlands, one thing you get used to is that a lot of city roads are actually made out of bricks. Not tarmac, or anything like that, but bricks. And every few years they get dug up because they've been laid on sand, and subsided. So the roads don't wear out, they just get pushed down. What this means in practice is that it would be quite practical to convert (over time) all the normal brick based roads to "green brick" roads. I think that this would prove to be quite a boost to the air quality of your typical high density Dutch conurbation. And I can't think of a reason why TiO2 salted bricks should be less physically durable than regular bricks.

Re:Two problems

[Anonymous Coward]

You need to stand next to the regenerator for a catalytic cracker (cat cracker) and realize how many thousands of horsepower go into cleaning up the catalyst.

Re:Two problems

[clyde_cadiddlehopper]

Is washing the surface a necessary step? If so, this might not be a great solution for L.A., Phoenix, and other cities in arid locations.

Re:Two problems

[mvdwege]

If it's nitrates, I wonder if the concentration coming from a road surface after rainfall is significant anyway. With current farming techniques, nitrate levels in the groundwater supply are already a problem, and processes to deal with that are already in place. The high-density pork and poultry farming techniques prevalent in the Netherlands produce huge amounts of nitrates.

If this road surface amounts to a drop in the bucket for our current nitrate problem, but cleans the air of pollutants, it might be a net win.

Mart

"harmless nitrates"

[mattpm]

I, for one, welcome our new Dutch Concrete overlords.

Re:"harmless nitrates"

[Killjoy_NL]

Ok I am ready to rule you insensitive clods ;)

This isn't that new

[Devon Dan]

This stuff isn't that new. It definately has been sold for quite a while under the name TX Active [ http://www.italcementigroup.com/ENG/Media+and+Communication/News/Corporate+events/20060228.htm ]. They used it to make the Air France head quarters at Charles de Gaulle Airport a few years back. http://www.physorg.com/news67012896.html

Re:This isn't that new

[j_snare]

You know, reading these two kinda puts the article from the summary in perspective. They have even less information about how it works than it does! Still, thanks for finding these, maybe we can find some more information based on the additional information here.

Re:This isn't that new

[apetrelli]

They did put it even in a gallery and in a church (Dives in Misericordia) in Rome.

For all the dutch people out here

[hee gozer]

A dutch version of TFA: http://www.autoblog.nl/archive/2008/08/04/hengelo-krijgt-straat-met-luchtzuiverend-beton

Groetjes!

like the song...

[Anonymous Coward]

Paved Paradise, put up a (purifying) parking lot

Wow, cool idea!

[bill_kress]

Maybe we could do even better.

Hmm, since we're being green anyway, lets eliminate some of the cars--then perhaps we could make the concrete softer to walk on.

We could use some other color but grey--yuck. Maybe green to represent the fact that it purifies the air.

Being softer, it would be nice if it had some kind of self-patching mechanism...

As long as it's going to be self-patching, let's get really sci-fi and have it create itself using some kind of a system involving materials from underneath itself in some kind of a synthesis process.

Damn, I'm thinking way too far ahead--our science will never get to the point where it can do this stuff. Guess I'll have to be happy with air-purifying concrete.

Re:Wow, cool idea!

[maxume]

So you grow all of your own food and don't rely on trucking for any of your other needs?

Color me impressed. Who ships computers by rickshaw?

Re:Wow, cool idea!

[Anonymous Coward]

One small problem with cities is that there is a thing called destinations. One thing about this is that people tend to walk in the same place over and over again.
I have never seen "green concrete" with a self-patching mechanism good enough to be used on areas made for walking, perhaps if we removed the walls from all building so that we didn't have dedicated entrances.

Re:Wow, cool idea!

[MightyYar]

I know you are joking, and it was actually pretty funny...

But grass makes a terrible surface for any high-traffic area. Look at what they have to do in New York's Central Park just to keep grass on all the lawns. They have to fence off areas, reseed, re-sod, fertilize and poison the holy hell out of everything.

Re:Wow, cool idea!

[Anonymous Coward]

Impressed is a texture, not a colour. Hold still while I get my hammer.

Re:Wow, cool idea!

[randyest]

If you're not joking then I hate you.

Re:Wow, cool idea!

[Anonymous Coward]

...and have it create itself using some kind of a system involving materials from underneath itself in some kind of a synthesis process

....I really hope everyone knows that the vast majority of existing materials (prior art) for such "green self repairing concrete" comes from the air and not from underneath itself. So that major difference alone would make your idea Sci-Fi for now.

Re:Wow, cool idea!

[bill_kress]

Also, it doesn't stand up to wheeled traffic like concrete does. Just seemed like one of those amusing cases where a solution loops back around to being nearly as good as the thing it replaces, but now someone makes money off it.

Meh...

[Thelasko]

Chicago is putting in water purifying concrete.

Re:Meh...

[martinw89]

Great, the water purifying concrete can purify the wash off from the air purifying concrete!

Too bad it's not ready...

[Ken_g6]

for the Beijing Olympics this year.

Hong Kong Polytechnic

[quanminoan]

I did some research for school over in Hong Kong for a few months and worked with the Hong Kong Polytechnic University Civil Engineering Dep. They used titanium dioxide coatings on bricks and highway noise barriers - actually in use in Hong Kong. They also have attached titanium dioxide nanoparticles to textiles to make filtering clothing:

http://www.polyu.edu.hk/cpa/polyu/hotnews/details_et.php?year=all&news_id=255

http://www1.polyu.edu.hk/hotnews/details_e.php?year=all&news_id=964

It's great to see it catching on...

Re:Hong Kong Polytechnic

[Anonymous Coward]

I've been coating my house with titanium dioxide coatings for years.

It's called white paint.

Don't worry, though. It's completely harmless.

[clone53421]

Harmless...

In freshwater or estuarine systems close to land, nitrate can reach high levels that can potentially cause the death of fish. While nitrate is much less toxic than ammonia or nitrite, levels over 30 ppm of nitrate can inhibit growth, impair the immune system and cause stress in some aquatic species.[citation needed] However, in light of inherent problems with past protocols on acute nitrate toxicity experiments, the extent of nitrate toxicity has been the subject of recent debate.

In most cases of excess nitrate concentrations in aquatic systems, the primary source is surface runoff from agricultural or landscaped areas which have received excess nitrate fertilizer. These levels of nitrate can also lead to algae blooms, and when nutrients become limiting (such as potassium, phosphate or nitrate) then eutrophication can occur. As well as leading to water anoxia, these blooms may cause other changes to ecosystem function, favouring some groups of organisms over others. Consequently, as nitrates form a component of total dissolved solids, they are widely used as an indicator of water quality.

What could possibly go wrong, though? It's not like roadways are "surfaces" that might "runoff" into storm sewers or waterways.

Re:Don't worry, though. It's completely harmless.

[hansamurai]

Harmless...

What could possibly go wrong, though? It's not like roadways are "surfaces" that might "runoff" into storm sewers or waterways.

We'll call it Mostly Harmless then.

Re:Don't worry, though. It's completely harmless.

[Anonymous Coward]

The proof that we won't reach "high levels" or "excess concentration" follows from these:

- NOx is much more toxic than nitrates,
- people aren't all dying on the streets,
- therefore there isn't enough NOx to convert to cause nitrate problems.

Re:Don't worry, though. It's completely harmless.

[clone53421]

Oh? NOx is a gas, and it escapes. Nitrate is water-soluble and it collects until rain dumps it all at once into a water supply. Now get off my lawn!

Re:Don't worry, though. It's completely harmless.

[randyest]

Hello? You copypasta'd a wiki page and even included the "[citation needed]", and this supports your fear?

Re:Don't worry, though. It's completely harmless.

[Anonymous Coward]

"While nitrate is much less toxic than ammonia or nitrite"

The idea is to convert nitrites into nitrates. I believe some other conversions may occur as well, such as carbon monoxide to carbon dioxide. Surface runoff is not much different than the acid rain or pollution rain that will eventually happen if the exhaust is left untreated. Only difference being that the rain will contain more harmful substances than the runoff from the road. Besides it's easier to have drains and water treatment for runoffs from roads than water treatment for the rain.

air treatment

[FudRucker]

why not get some crop dusters and fit them to release a fine powder of this air cleaning agent at high altitude above cities that have smog & air pollution problems?

what will it do to ground water and lakes & rivers? maybe clean them too?

What?

[Dunbal]

As a biologist I take exception to the phrase "harmless nitrates"!

      It may not have anything to do with greenhouse gasses, but more nitrates in rivers and ground-water is the last thing humanity needs.

Re:What?

[Killjoy_NL]

One thing is funny though.
Many years ago there was all this hubbub in the news about nitrates in washing powder.
They removed all of them and a while after that, I saw a report on plants dying because of lack of nitrates.

Re:What?

[Oktober Sunset]

no, no, I think you will find that packs of carnivorous dinosaurs roaming our streets is the last thing humanity needs.

Eutrophication

[Ritorix]

Likely washed towards the sea, causing algae blooms.

Re:Eutrophication

[Gat0r30y]

I thought we discussed this - Phosphorus is the limiting agent in algal blooms.

Re:Eutrophication

[jameskojiro]

Make the algae produce oil and it's a win-win....

Groundwater Pollution

[Skjellifetti]

Great. Now the nitrates are washed off by rainwater where it gets into the groundwater. The Dutch already have a significant problem with nitrate polluted groundwater due to farm animal wastes. The country has about 15 million people (versus about 8 million in Georgia) living in an area about a fourth the size of Georgia. They share the land with 4.7 million cattle, 13.4 million pigs, 44 million laying hens, 41 million broilers, and 1.7 million sheep. Altogether, those animals produce three to four times more manure than is needed to fertilize the country. The nitrate pollution problem is large enough and environmental regs are becoming strict enough that Dutch farmers are moving to midwest states in the U.S. with Right-To-Farm laws and far fewer environmental regs on farms. Dutch owned factory farm egg operations have caused several significant waste runoff problems in Ohio. Tell me again how this new fangled concrete solves the nitrate problem?

Someone Else's Problem Field In Effect

[markdowling]

Since the road would likely be paved with standard concrete anyway, the net effect is likely minor. Unless the concrete plant is in the vicinity, minor = irrelevant - politically anyway.

I would be more interested in the statement "green bricks" - is that in colour as well as pollutant effect? I'm wondering how the road markings contrast on a green colour background.

Re:Someone Else's Problem Field In Effect

[sumdumass]

I'm also wondering about a dust buildup that might make the road very slipery durring a rain or something. There is more to exhaust then nitrates so it has to go somewhere.. Unless I'm missing the point and the concrete traps the nitrates which doesn't seem right somehow.

Texas (or was it New Mexico?) had an issue like this a while back. They started brining roads in norther parts where it actually snows and freezes during the winter and they found that dust from being so dry in the months leading up to the winter, collected on the road and using the brine made a slick solution almost as slippery as oil on the road. I'm not sure if they figured that out yet. It was in the mid 90's when I was there last.

harmless nitrates?

[Easy2RememberNick]

The province I live in is currently going nuts over nitrate levels in the groundwater, high levels are a possible cause of cancer and can damage a person's health in other ways too.

Nitrates not so harmless! But it won't work anyway

[GPS Pilot]

the additive binds the nitrogen oxide particles emitted by car exhausts and turns them into harmless nitrates. "With one rain shower everything is washed clean," the institution said

Hmm... the New York Times says nitrates are "a dangerous and increasingly widespread pollutant... reaching dangerous levels in groundwater".

It seems environmentalists hold wildly diverging opinions on this.

If the NYT is correct, it's fortunate that this "air purifying concrete" is not likely to be very effective. You see, only a small percentage of the NOx molecules are going to come in contact with the road surface (which makes them eligible for conversion to nitrates). The titanium dioxide in the concrete is not able to reach out and grab NOx molecules floating one meter or even one millimeter above the road. I predict the air quality measurements will show very little difference, and the media will never report on this idea again.

For the system to be effective...

[SamP2]

Nitrates don't need to be harmless, nor there needs to be zero side effects. All that's needed is that the combined damage produced by any side effects must be less than the damage produced by the excess carbon dioxide in lieu of said concrete.

Funny how any time there is a proposed innovation to solve a problem, there are always nitpickers who point out side effects without considering their proportion compared to the original problem being solved. A solution either offers a net benefit, or it doesn't.

Re:For the system to be effective...

[rjstanford]

Similar to nuclear energy. The radioactive waste created by a modern reactor is less than that created by the mining process for a coal plant, when measured against the amount of power generated. The radioactivity from coal isn't all concentrated in one easy-to-handle package, though. I doubt that anyone would be terribly interested in "solving" the waste problem from a reactor by grinding it up small and dispersing it over a wide area, but that would actually be similar-to (and cleaner-than) the current coal process... if you include the whole life cycle.

Re:For the system to be effective...

[Anonymous Coward]

Except we're not talking about carbon dioxide, we're talking about oxides of nitrogen that lead to photochemical smog.

But, you are correct in what you're saying. A solution that increases surface run-off of bioavailable nutrients should, in my opinion, be accompanied by a solution to treat that run-off before it enters surface or groundwater. We know how to do it. We have the technology. It's called a "marsh." Man-made marshes are one of the most under-utilized form of surface water treatment, even though it's what nature decided to use and it's been working pretty well for a while. Until we though it would be a good idea to drain, dredge, and build on top of marshes.

Re:For the system to be effective...

[Anonymous Coward]

There is no objective, one-dimensional scale to rate and compare solutions.

Re:For the system to be effective...

[synaptic]

Funny how any time there is a proposed innovation to solve a problem, there are always nitpickers who point out side effects without considering their proportion compared to the original problem being solved. A solution either offers a net benefit, or it doesn't.

Propose to an Englishman any principle, or any instrument, however admirable, and you will observe that the whole effort of the English mind is directed to find a difficulty, a defect, or an impossibility in it. If you speak to him of a machine for peeling a potato, he will pronounce it impossible: if you peel a potato with it before his eyes, he will declare it useless, because it will not slice a pineapple.

* Charles Babbage, with regard to his Analytical Engine, the first programmable computer.

http://en.wikiquote.org/wiki/Charles_Babbage

Re:For the system to be effective...

[Nodamnnicknamesavial]

"All that's needed is that the combined damage produced by any side effects must be less than the damage produced by the excess carbon dioxide in lieu of said concrete."

Being that there is no actual scientific data on the damaging effects of carbon dioxide, this equation would be hard to solve. It's basically one imaginary "best guess" weighed against another.

Of course this is a statement of heresy, and I'm sure many will be quick to dismiss it, but please provide the data when you do. I'd be interested to peruse it.

Dumb comments about nitrates

[avandesande]

Please educate yourselves before posting dumb comments about nitrates.....

http://en.wikipedia.org/wiki/Nitrogen_fixation

Re:Dumb comments about nitrates

[clone53421]

http://www.google.com/search?q=nitrate+pollution
  http://www.google.com/search?q=EPA+nitrates
  http://www.google.com/search?q=DNR+nitrates
  http://www.google.com/search?q=nitrate+health

Yeah, everyone who thinks excessive nitrates are bad is stoopid.

Re:Dumb comments about nitrates

[avandesande]

These nitrogen oxides will eventually end up as nitrates anyway, the TIO catalysts just speed this up. Or would you rather that people and wildlife breath them into their lungs first?

Stupid.

Re:Dumb comments about nitrates

[clone53421]

Are you trying to say that nitrates are harmless, or that they're just "less bad than NOx"? Because last time I checked, TFA said they're "harmless".

Re:Dumb comments about nitrates

[avandesande]

Compared to nitrogen oxides they are.
The fuss over this is as stupid as a scientist making the statement "catalytic converters convert carbon monoxide into harmless carbon dioxide" and then people jumping all over them about global warming.

Stupid.

Re:Dumb comments about nitrates

[Red Flayer]

These nitrogen oxides will eventually end up as nitrates anyway

Maybe[1], but...

A diffuse source of nitrates is not as problematic as point-source creation of nitrates. High local concentrations of nitrates can lead to lots of problems, which have been pointed out elsewhere in the discussion, so I won't go into detail on those. When NOx is allowed to diffuse before being converted into nitrates, the harmful effects of the nitrates are much less.

I don't have the background & time to do a full analysis of what is more harmful -- NOx pollution + diffuse nitrate pollution vs. reduced NOx pollution + concentrated nitrate pollution... but there is more to the issue than just avoiding NOx. That said, the volume of NOx we produce via combustion is huge, and IMO is worthwhile.

[1] My understanding is that little NOx is converted to nitrates. Most instead is reduced to N2 by ozone. I could be wrong, it's been a very long time since I studied this... and I guess you could say that N2 is eventually converted to nitrates via nitrogen-fixing bacteria as part of the nitrogen cycle...

Re:Dumb comments about nitrates

[avandesande]

lightning is a huge source of fixed nitrogen (as nitrate) which starts out as nitrogen oxides.

Once again it's scientists vs /.ers pulling things out of their *ss.
 

Re:Dumb comments about nitrates

[clone53421]

Quit calling me stupid, stupid. Or do you work in an industry that gives you an excuse to actually talk about this as if you know anything?

Re:Dumb comments about nitrates

[avandesande]

I never said you were stupid, although I guess you just did ;)

Re:Dumb comments about nitrates

[clone53421]

Yeah, you did. Twice.

You also didn't answer my question... exactly what basis do you have for claiming to be knowledgeable on this issue?

Re:Dumb comments about nitrates

[avandesande]

Uh, Chemist? But even a cursory search on google backs up my assertions.

Re:Dumb comments about nitrates

[clone53421]

Oh really. Well I'm in the water treatment/purification business, and pardon me for raining on the parade (no pun intended) when someone suggests something that will result in more runoff. I don't know if the treatment is worse than the disease, per se, but it's nothing to be glibly raving about. "Harmless" it isn't.

Re:Dumb comments about nitrates

[Red Flayer]

lightning is a huge source of fixed nitrogen (as nitrate) which starts out as nitrogen oxides.

A huge source? Do you mean to say, a relatively minor source compared to the products of nitrogen-fixing bacteria? Because every source I just googled considers lightning to be a minor source (~10%).

I did have the reaction backwards in my previous post, however... NO or NO2 is oxidized to NO3-, not reduced to N2.

Anyway, I find it interesting that you called me out on a part of my post that was accurate, and didn't even bother with the inaccurate part... makes me wonder who is really talking out their ass.

Re:Dumb comments about nitrates

[Anonymous Coward]

Sumping my septic tank doesn't make you some kind of an expert.

Re:Dumb comments about nitrates

[clone53421]

I never said I sumped septic tanks. I'm more involved in taking brown smelly water and putting it in your faucet all shiny and clear.

Re:Dumb comments about nitrates

[Anonymous Coward]

It takes a hell of a lot more expertise to sump a septic tank than it does to shit in one, asshole.

Wouldn't it make more sense too...

[Dex5791]

Put this titanium dioxide-based additive in the exhaust systems?

Re:Wouldn't it make more sense too...

[allawalla]

If we could just figure out how to get sunlight in your exhaust...

Re:Wouldn't it make more sense too...

[zoefff]

As the saying goes:

Stick the TiO2 where the sun doesn't shine...

I for one

[Anonymous Coward]

welcomes our titanium dioxide enhanced rat overlords.

old news.

[nimbius]

this has been around since 2002. westminster and japan had it first. its called a noxer block http://en.wikipedia.org/wiki/Noxer_block

Re:old news.

[swordgeek]

Slightly different, I think. Rather than laying blocks, it appears that they're adding the TiO2 as part of the paving process for continuous concrete roads.

Hot Concrete

[AioKits]

With the way this concrete works, hopefully it will not get too hot, and make the world's largest Dutch Oven.

...

Okay, even I'm ashamed of that one.. Hehe, Dutch Oven..

WKMTTFA

[Saraphim]

This appears to be a similar product

http://en.wikipedia.org/wiki/Noxer

won't help CO2!

[datapharmer]

Well apparently this isn't going to improve CO2 levels much, since according to this website UV + titanium dioxide => CO2! Plus, based on the bug trap being sold at that link, I'm guessing that mosquitoes could pose a serious problem for this experiment...

sunscreen is cleaning the air!

[jackchance]

who knew that my titatium dioxide containing sunscreen was actually cleaning the air!

now beach-goers everywhere can claim to be active environmentalists!

old news

[Goldsmith]

In 1972 it was discovered that titanium dioxide is a strong oxidizer when exposed to light. The following years saw this applied to paints used in hospitals, coatings on windows and building concrete.

This is old technology which has been in use in Japan for many years. Yes, it does work.

Re:old news

[Anonymous Coward]

Yes, it is true that this is based on a Japanese invention. It says so even in the Universities press release. The trick of these new bricks is that the amount of titanium oxide that is needed is greatly reduced in comparison with previous applications.

Dirt of the road?

[wfstanle]

I'm wondering what the effects of dirt and oil from cars would be. Wouldn't these items dramatically reduce the effectiveness of the titanium dioxide? Still, titanium dioxide is a relatively harmless substance so I guess that it wouldn't hurt to try.

Not concrete ar asphalt but bricks

[BaatZ]

Minor error i know, but i just read it in my daily paper (het parool); researchers said asphalt and concrete (unless highly polished) wouldn't do the job.

Backwards

[DerekLyons]

I'm also a bit curious about the "harmless nitrates" that will be washed into the ground every time it rains.

Nitrate is also known as a fertilizer.

Actually, you have that backwards - fertilizer is also known as 'nitrate'. Not all nitrates are fertilizer however.
 
 

laying down fertilizer on their lawn, and shipping cut grass to landfills - leaving grass where it is provides the new grass with its own fertilizer.

Kinda, sorta. Mostly leaving cut grass where it is leaves you with a lawn choked with decaying grass. It takes a fairly thick layer to actually compost.
 
 

writing that nitrates can be worse than NOx (NO, NO2 and others)

What's wrong with writing the truth? Nitrates are poisonous in quantity, and even below toxic levels can cause algal and bacterial blooms in water and soil - blooms which can and do crowd out other organisms from the ecosystem.

Re:Backwards

[gnuman99]

"Mostly leaving cut grass where it is leaves you with a lawn choked with decaying grass"

That is only true if you are one of the nuts out there that thinks thick, blue grass with NOTHING else is a healthy environment. Why not just pave your lawn and put down carpet?

If you don't fertilize your lawn, the grass will be less thick, grows slower and be a little paler. At that point the clippings provide enough nutrients provided you don't kill everything with herbicides and pesticides.

even below toxic levels can cause algal and bacterial blooms in water and soil - blooms which can and do crowd out other organisms from the ecosystem.

I have yet to see an algae bloom in the soil!!

Aside from that, the cause of algae blooms is NOT nitrogen. It is phosphate. Phosphate is the limiting factor for aquatic algae. Aquatic environments already have enough nitrogen.

http://findarticles.com/p/articles/mi_m0NTB/is_8_41/ai_94333421

Re:Backwards

[Chosen Reject]

laying down fertilizer on their lawn, and shipping cut grass to landfills - leaving grass where it is provides the new grass with its own fertilizer.

Kinda, sorta. Mostly leaving cut grass where it is leaves you with a lawn choked with decaying grass. It takes a fairly thick layer to actually compost.

No, you really do want to leave it there. According to that link, leaving your grass clippings there actually helps to decompose thatch. I read in the Scott's lawn care book that mulching doesn't contribute to thatch and is recommended.

writing that nitrates can be worse than NOx (NO, NO2 and others)

What's wrong with writing the truth? Nitrates are poisonous in quantity, and even below toxic levels can cause algal and bacterial blooms in water and soil - blooms which can and do crowd out other organisms from the ecosystem.

No, nitrates have nothing to do with algal blooms

Re:Backwards

[DerekLyons]

If you don't fertilize your lawn, the grass will be less thick, grows slower and be a little paler. At that point the clippings provide enough nutrients provided you don't kill everything with herbicides and pesticides.

Um, no. They won't. They'll accumulate and choke out your grass while providing haven for fungus and moss which will further weaken your lawn.
 
 

Aside from that, the cause of algae blooms is NOT nitrogen.

We aren't discussing nitrogen - we are discussing nitrates. And yes, nitrates can contribute to algal blooms.

Re:Backwards

[Anonymous Coward]

What you're claiming is the exact opposite of the case with my lawn. I only rake the clippings (and not very thoroughly) maybe once a year when it gets way ahead of my cutting in the spring. The rest of the stuff breaks down roughly as fast as it gets cut.

Re:Backwards

[shawb]

Actually, you have that backwards - fertilizer is also known as 'nitrate'. Not all nitrates are fertilizer however.

Since everything else you wrote here has been debunked, I'll take on this line. Nitrates are one of many components of fertilizer. There are three main components that plants need in large quantities - nitrogen, phosphorous and potassium. There are also several other trace minerals that are required for plant growth and often included in fertilizer mixes. Fertilizer is essentially an addition to the soil of those chemicals that plants need to grow, and could be compared in analogy to human nutrition... the secret is in appropriate balance. So, the grandparent had it right. Nitrate is indeed a fertilizer, just as phosphate and potassium are. What you are used to buying and spreading on the lawn or garden is a blended fertilizer, made of several different types.

Re:Backwards

[DerekLyons]

Since everything else you wrote here has been debunked

Not one thing I wrote has has been debunked. Some folks think they have, but that's because they are ignorant idiots lacking reading comprehension and mistakenly believing that cutting and pasting is an adequate substitute.
 
Unless you mulch - grass clippings kills lawns. Mulching is not the same as leaving clippings on the lawn. Nitrates do contribute to algal blooms.
 

I'll take on this line.

You try and fail - because you don't even address the point you quote. You don't even bother to read it, let along think, but just regurgitate crap you read off the web somewhere with about as much understanding as the coffee cup beside my keyboard. Yes, nitrates are a component of fertilizer... But not all nitrates are fertilizers. (Nor are all phosphates.)

As usual

[omfglearntoplay]

The first post is always an ultra skeptical "this is useless/fake/junk technology that makes things worse/same/fail." It doesn't take much thought to kneejerk call something new wrong, but if you stop and fucking think about it for more than a nanosecond maybe you can see some good in something. Or maybe not, everything sucks, status quo, kill everything, nuke it from orbit to be sure, bye, thanks, peace, out.

Nitrates? Harmless?

[MadHakish]

Nitrates, Nitrites, and Ammonia are all incredibly toxic to fish, which if I'm understanding will simply be washed into groundwater/lakes/rivers by rain..

What sort of nitrate levels are we talking about here? If a pound of "greenhouse" gasses are converted by this new cement, what are the concentrations of nitrates released into the atmosphere, ready to be washed into bodies of water by rainfall?

Nitrates are absolutely dangerous, it's a matter of who they're dangerous for, and in what concentrations they are dangerous at..

Didn't RTFA btw..

Unless I'm missing something...

[Mashiki]

I'm wondering if it's based off this:

http://sciencelinks.jp/j-east/article/200416/000020041604A0544787.php but I'm still trying to figure out how it purifies the air, rather then cleaning the road surface. In the Japanese case, the material was applied into building panels which made them self-cleaning, with minimal discoloration after several years.

Maybe someone will be willing to explain it, otherwise the title/article are just misleading.

Any atmospheric scientist will tell you,

[pdxp]

Taking air quality measurements next to a road is not an indicator of the pollution caused by cars traveling on that road. A more long-term large scale study would be more appropriate as proof.

There are too many factors involved to take simple measurements, especially chain reactions whose effects are more evident farther from the road where it came from. Specifically, VOCs and NOx reacting to sunlight and creating ozone.

Or you can ignore all of what I just said and think about what would happen on a windy day :)

Al Gore?

[Dekortage]

Didn't you hear? He's busy sending his son into space.

How about...

[sholdowa]

As TiO2 is the main pigment in white paint, does this mean that a quick coat of emulsion will clean up all our cities???

Correct me if I'm wrong...

[s_p_oneil]

But doesn't hot air generally rise? And isn't the air that comes out an exhaust pipe generally hot? Even if not, wouldn't a mild wind make this fairly ineffective? Maybe everyone could bend their tailpipes to aim the exhaust downward, although I imagine that would mean people sitting in traffic would end up breathing a higher concentration of CO.

Street sweepers?

[bdwebb]

I'd be curious to see how well a standard city street sweeper would perform at removing the clogging elements.

In the event that they perform well, the environmental impact due to the production of the titanium dioxide may actually end up being less than the net reduction in pollutants with no extra effort required. Additionally, if the nitrates could be harnessed for use in city beautification projects and parks as fertilizer, this could be very beneficial for city streets. *shrug*

Or you could just have less kids.

[Anonymous Coward]

Or you could just have fewer kids.

Re:Or you could just have less kids.

[Anonymous Coward]

So what's your final answer? "Or you could just have less kids." or "Or you could just have fewer kids."

still old news.

[nimbius]

god damnit no it isnt.

RTFA.
concrete paving stones

green bricks

this shit has been around a long time. for greenland to start using it is nothing new

next, air purifying

[bugs2squash]

underpants...

Nitrates aren't harmless

[mark-t]

Although I'll concede they are a lot cheaper, you can still rack up a huge long distance telephone bill in a month just using the phone after midnight.

And of course...

[CptNerd]

Of course, they will discover that the "harmless" nitrates will cause rivers to choke on algae, due to the fertilizing effect of the nitrate runoff in the rain.

Mass transfer problems

[captainpanic]

I think that there is a mass-transfer problem. Wind (convection) is measured in meters per second, and it really beats diffusion which is... well... slower. It's not necessarily bad to remove a bit of NOx, but I doubt that 1 road is gonna make a lot of difference. A whole city covered in these stones, that might do something. The white paint on your walls is also white because of the TiO2 by the way. Perhaps we can turn our paint into a nitrate producing paint too (nitrate is also white, so who cares it'll stick to your walls)?

+1 Reverse analogy

[KlaymenDK]

I'm sure I speak for all of us when I say that we're sick and tired of car analogies.

But this computer analogy for cars? Hmm, you might have something there!

Cure worse than the disease?

[Anonymous Coward]

To all the people here complaining about the toxicity of nitrates, the huge algae blooms growing in the sewers and suffocating all the fish, and the general "cure is worse than the problem" attitude, let me share a little anecdote to put some "statistical reasoning" into your minds.

A decade or so ago, a couple of development workers went to an African country to take a look at the drinking water system that was installed there a few years before (by their predecessors). They were shocked to find out that the operators were adding a compound to the drinking water which was rather carcinogenic. They quickly calculated from the dosage and the number of people using the water that this would be responsible for dozens of cancer deaths each year. The operators shrugged and stopped pouring the stuff in.

The next year saw a rise of the number of difteria fatalities by several hundred.

I was also wondering

[FoamingToad]

about the effects of eutrophiciation (sp? too lazy to check the hivemind).

I'd expect that any nitrates thus generated would pretty quickly end up dumped into rivers in pretty short order.

I'm pretty sure that the drainage systems are intended to capture and process waste which may help, but there's still a fair amount of runoff into rivers, verges, &c.

May help fertilising the grass verges at the sides of motorways I guess.

Old hat

[macraig]

I believe I first saw this air-purifying concrete mentioned over two years ago, at a time when it was already seeing first applications. Somebody isn't paying attention.

Volvo clean air concept

[Anonymous Coward]

what ever happened to Volvo's concept of putting a special coating on radiators to clean the air.
how effective are those bricks in those areas where it doesn't rain for months and months?

Re:Offset? - tech breakthrough on its way

[proto]

MIT found some material for new and cheaper catalytic converters. Platinum is the so called "best" option today but its expensive. I think it can be a breakthrough if it can be applied to battery tech. Source of the MIT annoucement: http://www.itwire.com/content/view/19785/1066/

Gases

[Anonymous Coward]

Doesn't heated gas rise? Fat chance it touching the pavement.