China Builds 'World's Biggest Air Purifier' That Actually Works (scmp.com)

The South China Morning Post shares an update on the status of an experimental tower in northern China, dubbed the world's biggest air purifier by its operators. According to the scientist leading the project, the tower -- which stands over 328 feet (100 meters) tall -- has brought a noticeable improvement in air quality. From the report: The head of the research, Cao Junji, said improvements in air quality had been observed over an area of 10 square kilometers (3.86 square miles) in the city over the past few months and the tower has managed to produce more than 10 million cubic meters (353 million cubic feet) of clean air a day since its launch. Cao added that on severely polluted days the tower was able to reduce smog close to moderate levels. The system works through greenhouses covering about half the size of a soccer field around the base of the tower. Polluted air is sucked into the glasshouses and heated up by solar energy. The hot air then rises through the tower and passes through multiple layers of cleaning filters. The average reduction in PM2.5 -- the fine particles in smog deemed most harmful to health -- fell 15 per cent during heavy pollution. Cao said the results were preliminary because the experiment is still ongoing. The team plans to release more detailed data in March with a full scientific assessment of the facility's overall performance.

Comments

Grrr.

[Anonymous Coward]

Something seems wrong about this.
We shouldn't be purifying air, we should not be polluting in the first place.
This'll just allow people to continue polluting with natural gas to generate electricity (fastest growing fossil fuel electricity producer)

Re: Grrr.

[Anonymous Coward]

How much of a tree hugger do you have to be to complain about a solar powered pollution reducer?

Re:Grrr.

[bobbied]

How so? This device is designed to filter out small particles not CO2.

Natural gas actually is "clean" emissions wise, with very little other than CO2 and water being released. Small participates are not produced when burning Natural Gas, unlike fuels like coal and oil. So this "filter" doesn't help. Also "clean coal" involves scrubbers that filter out very small particles from the combustion emissions, then treat the rest to remove the bulk of the remaining pollutants other than CO2.

Here in the USA, we don't need this kind of thing, for the most part anyway. We have greatly cleaned up our automobiles and other emission sources to the point that this device would be nearly pointless. In China, they still openly burn coal and don't have the strong emissions controls on all the various emitters, so they are apparently left with the idea of trying this. I whish them luck, but it's not the solution, just a mediation strategy.

Re:Grrr.

[LynnwoodRooster]

A lot of the pollution in Beijing comes from the Gobi Desert. It is a fairly regular thing for fine desert dust to be an appreciable amount of the pollution. That seems worthwhile in terms of filtering - and it's a 100% natural source of "pollution" (which is more than just man-made stuff).

Re:Grrr.

[Zontar The Mindless]

You've never been to Beijing, have you? The dome of smog surrounding the city is visible from 100 km away, and it's not caused by a big pile of dirt from the Gobi just deciding it wants to live there.

Re:Grrr.

[bobbied]

Properly pre-processed, such pollutants are extremely limited compared to coal or liquid fuels.

For example... Sulfur dioxide from coal is 2.591 lbs/MMBtu where natural gas emits 0.001, Nitrogen oxides are reduced from 0.457 to 0.092, and where coal emits 0.000016 of mercury, natural gas emits none. https://en.wikipedia.org/wiki/...

Natural Gas also emits less CO2 than coal. So all around it's a winning choice until other sources of energy come on line.

Personally, I would advocate that we use it instead of diesel and gasoline as a motor fuel because of this reduction in emissions as it is able to be used in *existing* internal combustion engines with little modification and we in the USA have a bunch of Natural Gas...

Re:Grrr.

[LynnwoodRooster]

I lived in Shanghai for 6 years, and have been traveling to China (and living, at least 3 months each year) for 20. I've been to Beijing countless times. Yes, a lot of it is smog - but when the wind blows out of the West, a lot of the brown you see is actually dust from the Gobi. Much like we get sand in Hollywood Beach, CA and you get dust in your house around harvest time near any wheat farm.

Re:Grrr.

[thegarbz]

Yeah dust. As a general clue if your pollutant is big enough to settle in your house and natural enough that it doesn't cause cancer then it shouldn't be compared to smog.

Dust storms and the cloud that rises from the city centre are two very different things.

Re: Grrr.

[BKX]

No they don't. Natural gas doesn't produce particulates. Natural gas is methane and hydrogen. Methane, when burnt, produces carbon monoxide and water. Carbon monoxide, when burnt, produces carbon dioxide. There's a bit of a small hydrocarbon produced as well but it's a gas and, when burnt, produces carbon monoxide, carbon dioxide and water. Natural gas also contains small amounts of ethane, but that also burns to gases. There are no carbon chains produced, like there would be with larger hydrocarbons, which means no particulates, since particulates are carbon chains with little to no hydrogen on them. The only particles that are produced are a small amount of single and dual atom carbon, which is gaseous and highly reactive, which means they're not really particles and they don't last long anyway.

Re: Grrr.

[Anonymous Coward]

Wait, doesn't that description fit trees themselves?

Re:How long would the filters last?

[Thelasko]

How long would the filters last?

There are ceramic filters that can be baked to burn the soot collected. If I were to build this, it's what I would use. No point cleaning up pollution by creating even more pollution.

Re:Sci-Fi future

[bobbied]

This level of both technology and organization of it is beyond the capability of probably all Western nations now.

Right... Actually we in the western industrialized world do this at the actual emission point instead of dumping it into the air and then filtering it out... We've got scrubbers on our Coal burning plants, emissions controls on our cars and trucks and strict controls on all sorts of things that cause air pollution. We've done a really good job of this actually, and our air quality has vastly improved since we got really serious about it in the 70's..

You remember that VW emissions issue? What do you think this was all about? We've got laws for this, and we enforce them.

This isn't some technological marvel.. It's a desperate attempt at putting a Band-Aid on a huge emissions problem that they really cannot afford to fix the right way....

So

[IWantMoreSpamPlease]

No firing 10mm explosive tip caseless under the primary heat exchangers, right?

Re:So

[grub]

That's great. That's just fucking great! Now what the fuck are we supposed to do?

Re:So

[nasch]

Flame units only.

Math

[Solandri]

improvements in air quality had been observed over an area of 10 square kilometers (3.86 square miles) in the city over the past few months and the tower has managed to produce more than 10 million cubic meters (353 million cubic feet) of clean air a day since its launch.

10 million cubic meters spread over 10 square kilometers is (10 million m^3) / (10 km^2) = 1 meter. So over such a wide area, this thing is only cleaning a 1 meter thick layer of air.

Re:10 square kilomethers

[arglebargle_xiv]

the tower has managed to produce more than 10 million cubic meters (353 million cubic feet) of clean air a day since its launch

They also forgot to mention that it's coal-fired.

Bigger Picture

[mutantSushi]

So to have significant effect, such a system would need to be installed on many flat-topped buildings in urban areas, or open ground. If you're going to do that, why not install solar power generators in the same places, which reduce need for dirty power generation? The system is de facto using clean power generation potential for air filtering, albeit in efficient manner (due to direct utilization of solar thermal energy), but I question it's total utility value. China is already pushing electric cars etc heavily so that source is not a long term problem.

I would supposition that plant based air cleaning systems, whethe normal plants like http://mashable.com/2017/02/09... or moss like https://futurism.com/4-citytre... can be installed even more places, even filling vertical walls, effect not dependent on large single areas to support 'chimney' etc, and actively clean the air in even more ways, as well as adding oxygen.

Although on the other hand, the chimney filter system can very well be applied where heat chimneys already inherently serve climate control cooling function for buildings, and designing buildings with this approach in mind reduces need for air conditioning etc thus reducing electric consumption.

15 million people with handheld fans...

[fatp]

China has proposed to make 15 million people with handheld fans to blow smog away .
While this may not be called 'build', it must world's biggest air purifier.
http://shanghaiist.com/2017/11...

Re:10 square kilomethers

[Barsteward]

indeed, flat as a pancake.. i guess now he'll be falling back onto that as an excuse