Live data from Hacker News

China builds ‘world’s biggest air purifier’ and it seems to be working

scmp.com

31–40 of 78 posts

Re: China builds ‘world’s biggest air purifier’ and it seems to be working

#31

This may sound like a naive question, but how does this compare to say, trees?

Trees don’t do much for PM2.5. They are a reasonable solution for dust storms, which do generate lots of (but not all) PM10.

Re: China builds ‘world’s biggest air purifier’ and it seems to be working

#32

Side node: is China doing ok in terms of innovation? If yes, how come in such a regime? I would expect everything to be stuck in bureaucracy.

The bureaucracy typically help business when it works. It’s not meant to be directed by day-to-day driven politicians or exposed to lobbyism. It’s supposed to be a safety net to make sure society keeps on track as it speeds along.

That’s what it is in China, with the added benefit of it actually supporting their local and hindering foreign businesses.

In a lot of areas it’s us in the west who are stuck behind a hopelessly inefficient bureaucracy, but on the upside, you’re less likely to drop through a poorly constructed escalator or have your local lake filled with industrial waste (well, unless you’re American I guess).

Re: China builds ‘world’s biggest air purifier’ and it seems to be working

#33

Please refrain from using AMP links. We need to take a stance against Googles abuse of monopoly.

Devil's advocate: Google is generous by caching AMP sites on their own servers. The only thing you can't do is to include your own invasive third party tracking (ok, you can use Google's of course), which is bad anyway. But you can still include your ad just as a in the page, no JS and tracking. Like a dumb print ad. I don't really have a problem with that.

Re: China builds ‘world’s biggest air purifier’ and it seems to be working

#34

Side node: is China doing ok in terms of innovation? If yes, how come in such a regime? I would expect everything to be stuck in bureaucracy.

The bureaucracy typically help business when it works. It’s not meant to be directed by day-to-day driven politicians or exposed to lobbyism. It’s supposed to be a safety net to make sure society keeps on track as it speeds along. That’s what it is in China, with the added benefit of it actually supporting their local and hindering foreign businesses. In a lot of areas it’s us in the west who are stuck behind a hopel…

Our local lakes are still pretty clean, Trump hasn’t dismantled the EPA (yet). Western bureaucracy differs from Chinese bureaucracy in that it is more deterministic, the rules are more obvious and more fairly enforced. In China, there is a huge difference based on your guanxi level. I wouldn’t trade our system for theirs.

Re: China builds ‘world’s biggest air purifier’ and it seems to be working

#35

Please refrain from using AMP links. We need to take a stance against Googles abuse of monopoly.

Devil's advocate: Google is generous by caching AMP sites on their own servers. The only thing you can't do is to include your own invasive third party tracking (ok, you can use Google's of course), which is bad anyway. But you can still include your ad just as a in the page, no JS and tracking. Like a dumb print ad. I don't really have a problem with that.

"Google is generous by storing your email on their own servers."

"Facebook is generous by storing your posts and friend lists on their own servers."

Re: China builds ‘world’s biggest air purifier’ and it seems to be working

#36
post #6

I wish there was some technical background of what such a "purification tower" does. If they found a genuinely innovative way of purifying air and dumping the toxins and by products sensibly, that is mazing for all of us kudos to them! However, if they tried to push the problem away by shooting polluted air away and sucking in fresher air, then it sucks.

It says in the article that >"The hot air then rises through the tower and passes through multiple layers of cleaning filters." Meaning you just have to clean the filters

I think we should find a better way to heat ourselves without burning coal, because this air purifier will reach a limit in the future and we will be back on step one.

Re: China builds ‘world’s biggest air purifier’ and it seems to be working

#37
post #13

So... to drop the PM2.5 amount by 15%, this tower must be removing many many tons of particulate matter every day. How is it removed from the filters they speak of? How expensive is that to do? I have some questions about the practicality. On the other hand, I wonder if anyone's ever built a 100m placebo before. It could be a really interesting university study on the placebo effect in disguise.

> many many tons of particulate matter every day

Let's do the math.

Guidelines state that the limit on PM2.5 particulates is approximately 10 micrograms per cubic meter for an annual average. Xian, where the tower was installed, is currently (http://aqicn.org/city/xian/) under 231 ug/m^3 of pollution. The tower is supposed to process 10 million cubic meters of air per day.

    10^7 m^3 x 231 x 10^-6 g/m^3 x 10^-3 g/kg x 0.15 = 231 x 0.15 x 10^-2 =>
0.34 kg of particulate contamination removed per day. Not many tons. But someone check my math, please - that seems impossibly low, unless combustion is cleaner and generates lower quantities of PM2.5 particulates than I'm imagining. I did assume that it only removes PM2.5 contaminants, ignoring larger dust particles and PM10 pollution.

Let's also check the amount of air it should be processing. It's about 100 meters tall, and intended to cover 10 square kilometers. We'll conservatively assume that this volume represents the total quantity of air it needs to process. Ihe volume is:

   10 km^2 x 10^3 m/km x 10^3 m/km x 10 ^ 2 m = 10^8 m^3
or 100 million cubic meters, so it's intended to process one tenth of that volume per day.

The math still seems low. Micrograms per cubic meter are hard to intuit.

Re: China builds ‘world’s biggest air purifier’ and it seems to be working

#39
post #35

Earlier quoted context omitted.

Devil's advocate: Google is generous by caching AMP sites on their own servers. The only thing you can't do is to include your own invasive third party tracking (ok, you can use Google's of course), which is bad anyway. But you can still include your ad just as a in the page, no JS and tracking. Like a dumb print ad. I don't really have a problem with that.

"Google is generous by storing your email on their own servers." "Facebook is generous by storing your posts and friend lists on their own servers."

I agree

Re: China builds ‘world’s biggest air purifier’ and it seems to be working

#40
post #6

Earlier quoted context omitted.

It says in the article that >"The hot air then rises through the tower and passes through multiple layers of cleaning filters." Meaning you just have to clean the filters

I think we should find a better way to heat ourselves without burning coal, because this air purifier will reach a limit in the future and we will be back on step one.

To reduce air pollution the Chinese government forbad heating with coal in some regions and installed gas pipes there. It turned out they severely underestimated the spike in demand in winter and the rising gas prices. Residents illegally switched back to coal heating because heating with gas was 2-3x more expensive. Later, the government officially sanctioned coal heating for the time being. So the Chinese government tries to get away from coal but it’s not as easy.
Post reply on HN