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Self-Cleaning Buildings to Fight Smog
bryan8m writes "Using technology already available for self-cleaning windows and bathroom tiles, scientists hope to paint up cities with materials that dissolve and wash away pollutants when exposed to sun and rain. The idea: UV rays hitting the titanium dioxide coated cement and concrete trigger a catalytic reaction that destroys the molecules of pollutants, including nitrogen oxides."
Bo-Erik Eriksson, head of research at Cementa, another company participating in the Swedish-Finnish project, said the byproducts of the reaction, called photocatalysis, are benign, though it depends on what substances are involved: Organic compounds are broken down into carbon dioxide and water, while the nitrogen oxides yield nitrate salts.
Carbon dioxide and water are easy enough to take care of. Not sure what to do with the nitrate salts. Fertilizer?
The rationale here being the DC will ionize the air, charging the impurities, thereby encouraging them to head for and adhere to these pollution-destroying buildings.
Incidentally, ionizing the air is NOT a new concept. Its been happening in nature since Earth began... especially during thunderstorms when the air is so charged it breaks down - we call it lightning.
I have often wondered if dirgibles, charged from being moored to the business end of a large vandergraff generator ( several stories tall ) would do the trick.
If a small electrostatic generator drops the crap out of the air in a room, would a bigger one clear stagnant air over an entire city... such as the Los Angeles basin?
"Prove all things; hold fast that which is good." [KJV: I Thessalonians 5:21]
Outside of certain cities, such as Athens and Tehran, motor pollution is not such an issue anymore, as we all have catalytic convertors fitted to our cars (at least we do in the EU). Unfortunately, its still pumping out CO2. What is required is a catalyst which turns CO2 into Carbon and Oxygen. Unfortunately outside of plants and trees we don't have one. I suspect the worlds largest polluter will have to do better than this.
"XML is like violence. If it doesn't solve your problem, use more." - Anonymous Coward
Pollution causes decreased life span and quality of life. Whether you (or even your parents) lived in a clean environment or a polluted one, can determine whether you'll have all sorts of allergies, cancer, respiratory tract diseases etc. Even if you regularly check for cancer and catch each one in time, try to prolg your lifespan with antioxidants and reduced intake of calories, pollution will still get you: you may attain longer life, but with much reduced mental capacity or even dementia.
So, if you're a geek and you value your grey matter, you'll take pollution seriously.
In my view, one of the best ways around pollution is greater use of public transportation (expecially trains and such) - this is a problem in the US, where the existing public transportation companies have been bought and dismantled shortly after WWII - and greater utilization of nuclear, hydro, solar and wind power plants for production of electrical energy.
Sigged!
Put a tax on carbon based fuel sources. Start at 1%. Then increase it by 1% each year.
Deleted
OMGS you suggested nuclear die die planet killing scum!
[/sarcasm]
Seriously though, whilst I'm all in favour of nuclear it lacks a lot of public support.
A better idea would be to plant rooftop gardens, and hang cylindrical turbines off the sides of buildings. Cities act like big wind tunnels between tall buildings, cylindrical turbines could be used to turn this air into power for the building whilst the garden on the top helps buffer some of the pollution and generally make a nicer place.
Alternatively, make the centre of large cities pedestrian only.
How many people can read hex if only you and dead people can read hex?
It would make more sense to advocate roof gardens, street trees, and vines. These would have similar effects, but function more efficiently. Plants have the added advantage of making environments desirable to humans.
The average 2004 passenger vehicle sold in the US produces 227HP, 169.274KW. So 1477 cars, or a quarter-mile of every rushhour freeway, produces as much power as a 250MW coal plant. Find the relative "smog efficiency", and you've got the miles of freeway - probably not more than a mile or two - that is actually worse pollution than a plant. Most cities have dozens or hundreds of miles of traffic, compared to 2000 250MW coal plants (5E12W total US coal-> electricity / 250MW).
:). The energy for the decomposition reaction is the critical limiting factor. So the way to go is a solar surface, with pits for absorbing gas. Beneath the surface, their nanotech TiO deposition should create vast fractal surface areas within a milimeters layer, backed by exhaust/drip channels. The solar power drives UV LEDs from the rest of the incident spectrum, and perhaps some transport (nanofans?) to augment the diffusion flow across the enclosed active catalyst surface. Then these tiles get maximum efficiency from every factor in the process.
Coal plants might still put out more smog than do cars, but they're clearly in the same league. And cars, especially the SUV fraction of that raises the 2004 HP average so much, have much less emissions scrubbing than do centralized coal plants. So the car smog cycle needs extra special attention.
Also remember that these scrubbing building surfaces scrub smog from both cars and smokestacks. So the fact that both cars and coal need cleanup, and that these surfaces do both, makes the false choice you propose no problem: rather, it points at the promise of this tech as a combined solution.
Of course your suggestion about using the surface entirely for zero-emissions solar collection is probably right, if perhaps for the wrong reasons
The missing factors which decide everything about these tiles are the pollution numbers on their manufacture/installation/recycling, and their productivity during their lifetime: both the ones in the article and the SF version I just proposed. If the passive "real thing" is actually better than its pollution cost of use, instead of the alternative "dirty" tiles, then my "active" version will likely be even better. But will it still be a better pollution cost:benefit than a centralized scrubber, running off a high-efficiency (energy) gas-fired plant? Or is all this tile tech talk just hype, making more pollution to use the tiles than they clean in their lifetimes? Even more interesting, how do any of these technologies compare to just planting a lot of trees, maybe all across the surface of the buildings, and around the grounds?
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make install -not war