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Air pollution linked to “huge” reduction in intelligence

unenvironment.org

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Re: Air pollution linked to “huge” reduction in intelligence

#181

Earlier quoted context omitted.

It's a very easy way to talk about childhood progression under compulsory education, yes. But if not everyone is in school then I don't know whether "losing a year" means losing the schooling, or losing the year of development. More crucially, the main result here was about older adults losing capacities. If someone tells me that a 70 year old dementia patient has effectively "lost a year of education", I don't have…

You might consider other metrics, like the school grade level that most journalistic entities write for. In the USA, it used to be that most journalists wrote towards a 5th grade reading ability. Assuming that the article is correct, then many journalists who sell to air-pollutant-exposed people (which is most people) should be targeting a 4th grade reading ability, perhaps even lower. On a wild tangent, there has be…

This got me curious: are most Americans exposed to these pollutants at a meaningful level?

In short: no.

In long:

This study was done in China, and asked "what would happen if we lowered 10 micron particulate pollution levels to the US EPA standard?" Air pollution in China is substantially worse than in the US, and 10 micron particulates (PM10) are one of the largest points of divergence: China relies heavily on unfiltered coal burning for electricity, as well as conducting mining and road construction with minimal particulate control.

Unfortunately I can't get the API data appendix for the study, and the paper's figures are functions of mean API, but the data shouldn't be paper specific. All sources I can find agree: fine particulate pollution levels in China are horrifying. Almost all of China is consistently exposed to more than 40 micrograms per cubic meter of PM10 particulates, and urban centers are consistently much higher. Recent progress has lowered average rates in many cities into the 40-100 microgram window, but in 2010 annual average rates commonly exceeded 150 micrograms, which is the acute (24 hour) threshold set by the EPA.

The benchmark value in the study was 50 micrograms per cubic meter, which was (until 2006, when the standard was scrapped), the EPA's safe limit for annual average exposure. In America, across several hundred sites monitored in 2017, zero exceeded 100 micrograms, only four exceeded the 50 microgram threshold, and only twelve exceeded 40 micrograms. For 2016, those numbers are zero, four, and ten. The hardest-hit sites are all in the Southwestern US, which suffers from both dust and wildfire particulate matter frequently.

Further, not all PM10 particulates are created equal. They're grouped in a single number because the usual focus of concern is inhalation leading to lung problems, but when discussing cognitive effects they're almost certainly not equivalent. In particular, PM2.5 (2.5 micron particles) are a subset of PM10, and are both more likely to enter the bloodstream and more likely to be bioactive substances like metal, organics, or soot. Particulates between 2.5 and 10 microns are more likely to be dust, pollen, or ash - damaging to lungs, but much less likely to cause systemic harm. This study did admirable work controlling for or disproving confounders - I'm genuinely very impressed by how well they covered that base. But the PM10/PM2.5 conflation was inescapable since PM2.5 is a subset of the variable and wasn't measured separately.

(The study relied on an Air Pollution Index observing sulfur dioxide, nitrogen dioxide, and PM10, with the value controlled by the highest subfactor. From the references exclusively to PM10 and from China's other data, I assume that it was consistently the dominant factor, as it is in the US, but if it correlates with the other factors then one of them could potentially drive the effect. Nevertheless, SO2 and NO2 are essentially acute-only problems in the US, with average rates well below EPA thresholds.)

The highest-PM10 sites in the US look prone to dust and ash pollutants, and indeed checking the data says that their PM2.5 levels, while high, trend linearly up from other sites while their PM10 levels rise exponentially. The worst PM10 sites have PM2.5:PM10 ratios of around 20%. The highest PM2.5:PM10 ratios are between 50% and 70%. These are predictably found in industrial Rust Belt cities like Dearborn and Steubenville, but the total levels are still relatively low. 13 cities exceeded the annual EPA standard of 12 micrograms, and none exceeded 17 micrograms. 21 cities had 98th percentile rates in excess of the EPA daily standard of 35 micrograms; excluding outlier Phoenix (146 micrograms) the highest was 67 micrograms.

Meanwhile, China's PM2.5 rates have only recently been measured, but are terrifyingly high. China sets 0-35 micrograms as a Grade I success and 35-75 micrograms as Grade II success. Wuhan, selected as an average Chinese city for a study in 2013, exceeded the Grade II standard 75% of the time, and exceeded 150 micrograms (which, again, is the acute PM10 threshold!) 25% of the time. National samples show all cities profiled have PM2.5:PM10 ratios above 50%, and some exceed 80%. Most days in most cities in China, the PM2.5 level is higher than the highest observed rates for any site in the US except Phoenix.

Where does this leave us? China's PM10 rates are vastly higher than the worst American rates. China's PM2.5 rates, which are likely more relevant, are even more divergent. Annual NO2 and SO2 rates in the US are insignificant. The available evidence suggests that under any plausible shape for this effect - linear or exponential, threshold or LNT - its effects would be immeasurable anywhere in the US except perhaps 2-3 weakly affected cities. In all cases, other known impairing pollutants like carbon monoxide would be far more impactful.

This has been quite a tangent, but overall it's increased my appreciation for this study, while leading me to believe this result is basically irrelevant to US analyses.

Re: Air pollution linked to “huge” reduction in intelligence

#182
post #2

In case anyone else wanted to quantify "huge": > “Polluted air can cause everyone to reduce their level of education by one year, which is huge,” Yale School of Public Health's Professor Xi Chen, one of the report's authors, said in an interview published in The Guardian.[0] [0] https://www.unenvironment.org/news-and-stories/story/air-pol...

And to quantify pollution: the study looks at reducing 10 micron particulate pollution in China down to the EPA-approved limits, which almost all US cities are already below, and which Chinese cities are often 2-3 times above.

I tried to take a serious stab at "what does this mean for air in the US?", and my best conclusion is "probably almost nothing". The full notes are here: https://news.ycombinator.com/item?id=18231784

Re: Air pollution linked to “huge” reduction in intelligence

#183

Earlier quoted context omitted.

You might consider other metrics, like the school grade level that most journalistic entities write for. In the USA, it used to be that most journalists wrote towards a 5th grade reading ability. Assuming that the article is correct, then many journalists who sell to air-pollutant-exposed people (which is most people) should be targeting a 4th grade reading ability, perhaps even lower. On a wild tangent, there has be…

This got me curious: are most Americans exposed to these pollutants at a meaningful level? In short: no. In long: This study was done in China, and asked "what would happen if we lowered 10 micron particulate pollution levels to the US EPA standard?" Air pollution in China is substantially worse than in the US, and 10 micron particulates (PM10) are one of the largest points of divergence: China relies heavily on unfi…

I imagine most people aren't going to read that whole comment, but I did. Thanks for the write up, and for showing that my knee-jerk interpretation was incorrect.

Re: Air pollution linked to “huge” reduction in intelligence

#184
post #173

Earlier quoted context omitted.

For what it's worth, I wear a respirator[1] when I take the subway. Some people may look at you, but I don't really care. That being said, I recall reading an article where they said studied long term subway commuters and did not find health issues due to commuting. Furthermore, you can apparently build an air filter for the fraction of the cost: https://www.youtube.com/watch?v=q45CkwKiOvw [1] like the "3M Aura Parti…

Do you live in NYC? and have you found that it helps?

I commute to NYC. Yes it reduces the subway smell substantially.

Re: Air pollution linked to “huge” reduction in intelligence

#185

Earlier quoted context omitted.

A city that was never designed for bikes is hell for bikes, so you end up with only the most reckless bikers on the road. I commute with a bike every day in Paris, France. The infrastructure isn't great but it's OK, and it's improving. The thing is: I'm a big, strong guy who can legally outrun most cars and motorbikes in such a big, dense city. I can fight my way in traffic, mostly because the law authorizes bikes to…

I think I rode a taxi in Paris once or twice, but never a private car - and none of our friends had private cars, either. I assumed parking was a nightmare, and expensive. The narrow medieval roads didn't help, either. Many of the streets around our apartment were closed to cars (at least on Sunday). Being a cyclist, I thought I found a slice of heaven. I thought about being an urban planner when I got back to the St…

>I assumed parking was a nightmare, and expensive.

I've been a car driver and a cyclist there for ~10 years now. Believe me, being the former is much easier than the latter. If you're on a bike, many assume you're just having a good time (either on vacation or unemployed, as many people says) so the politicians/police/media won't care about your well being and focus instead of the transportation means of "serious people", i.e cars and motorbikes.

It's insulting, because I do have a car (and a parking spot) but everything pushes me to drive it instead of riding my vélo (which makes no noise, does not emit anything, takes very little space, doesn't damage the road, is far less dangerous to others, makes me fit and save health insurance costs...). Go figure.

Re: Air pollution linked to “huge” reduction in intelligence

#186

Earlier quoted context omitted.

Oh yes. As a Parisian and a big supporter of the electrification of all terrestrial transportation, I want as few EVs as city as possible. Cars simply don't make sense in dense cities (bikes do).

I lived in Paris for a spell, and one of the great things about the city is that it is so bike-able. It's not a large place! And it's dense. Lots of traffic, but the French seem to understand that bikes belong. We almost never used the Métro, what was the point? Saved money and no one ever stole my wallet!

I take my vélo at least twice a day (to commute) and I still find it far more distressing than taking the bus/métro. No wonder why so few people rides bikes, expect on the week-ends: with all the big petrol cars and aggresive motorbikes, it is still pretty dangerous to ride and not (yet) agreeable. But things are improving so I'm optimist and resigned.

Re: Air pollution linked to “huge” reduction in intelligence

#187

Earlier quoted context omitted.

This got me curious: are most Americans exposed to these pollutants at a meaningful level? In short: no. In long: This study was done in China, and asked "what would happen if we lowered 10 micron particulate pollution levels to the US EPA standard?" Air pollution in China is substantially worse than in the US, and 10 micron particulates (PM10) are one of the largest points of divergence: China relies heavily on unfi…

I imagine most people aren't going to read that whole comment, but I did. Thanks for the write up, and for showing that my knee-jerk interpretation was incorrect.

Hey, I'm glad someone did!

You offered an interesting thought, and I couldn't find anybody actually taking on "how does this compare to USA data?", so it was as much to settle my own curiosity as anything.

Re: Air pollution linked to “huge” reduction in intelligence

#188
post #166

Earlier quoted context omitted.

This World Resources Institute graph^1 shows intense growth in solar electricity generation in China so they are at least moving away from fossil fuel electricity generation at a rapid pace and fossil fuel electricity generation is plateauing^0 [0] https://en.wikipedia.org/wiki/Electricity_sector_in_China#/m... [1] https://www.wri.org/blog/2018/08/distributed-solar-pv-china-...

> fossil fuel electricity generation is plateauing^0 The graph you linked mostly shows exponential growth, with a slowdown in the last measured year. But similar kinks are visible twice before, with growth continuing at the same pace afterwards. I wouldn't call that "plateauing".

Well, there is another factor, the actual push to renewable energy sources and the fact that the cost of the next trillion watts of renewable energy will cost half the first https://www.bloomberg.com/news/articles/2018-08-02/green-ene...
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