Damage from Air Pollutants You Won’t Hear About from Your Doctor

Yves here. While this warning about the health costs of air pollution are important, I wish they had provided some advice. Even if the point is to spur collective action, it will take some time for any meaningful concrete action to occur.

For the curious, you can see which world cities rate well and poorly on air quality here.

By Sandra Aguilar-Gomez, Assistant Professor of Economics, Universidad de Los Andes; Visiting Scholar, University of California, San Diego; Holt Dwyer, Graduate student, University of California, San Diego; Joshua Graff Zivin, Professor of Economics, UC San Diego; and Matthew Neidell, Economics Professor, Department of Health Policy and Management, Columbia University. Originally published at VoxEU

A significant body of evidence has established the effects of air pollution on diagnosable health outcomes, ranging from breathing problems and low birth weights to hospitalisations and deaths. But the burden of disease is not the only economic cost arising from poor air quality. This column discusses an emerging body of work that suggests air pollution may have significant effects on day-to-day functioning, economic output, and individual wellbeing in cities around the world, even for people with none of the observable health problems typically attributed to pollution exposure.

Last year, the WHO revised its global air quality guidelines, recognising air pollution as “the single biggest environmental threat to human health” and noting that “[t]he burden of disease resulting from air pollution also imposes a significant economic burden” (WHO 2021). But the burden of disease is not the only economic cost arising from poor air quality. An increasing body of work shows that exposure to air pollution, even at the relatively low concentrations found in developed countries, can have meaningful impacts on both physical and cognitive performance. Though not diagnosable as diseases, these effects of air pollution have meaningful impacts on our economic output and well-being.

Some of the ‘non-health’ effects of air pollution are nearly contemporaneous with the pollution exposure itself and represent short-term reductions in performance measured relative to days or areas with less pollution. Other impacts are detectable many years after exposure and manifest as accrued physiological damage significant enough to affect behaviour, but below the threshold that would lead to a medical diagnosis. From a policymaking perspective, the findings from this literature imply that even small improvements from relatively low baseline levels of air pollution exposure may have substantial economy-wide implications.

Immediate impacts of air pollution include reduced productivity at work. Investigations of the effects of air pollution on workers in industries as disparate as professional sports (Lichter et al. 2017, Archsmith et al. 2018), garment production (Adhvaryu et al. 2019), agriculture (Graff et al. 2012), call centres (Chang et al. 2019) and the court system (Kahn and Li 2020) have found that exposure to air pollution reduces worker productivity (though He et al. 2019 finds negligible effects in a severely polluted factory setting). These studies show that the level of air pollution on a given day impacts worker productivity even for healthy workers; the harm caused by air pollution is not solely the result of medical conditions caused by prolonged exposure. This effect on the productivity of workers on the job is separate from the effect of air pollution on labour supply; several studies find that increases in air pollution reduce labour hours (Aragón et al. 2017, Hanna and Oliva 2015, Holub et al. 2021). Studies that look at production at larger scales, rather than focusing on particular worksites or cities, also find meaningful impacts of air pollution on overall output (Decelerate et al. 2019, Fu et al. 2018).

The finding that air pollution reduces productivity in physically demanding jobs is consistent with longstanding evidence on the deleterious impact of air pollution on the circulatory system. But recent biomedical research also suggests a link between air pollution and neuroinflammation in the brain. This link may explain repeated findings of cognitive and behavioural effects of air pollution that are hard to attribute to cardiovascular impairments.

A small but growing literature studies how pollution makes it harder to think, in both academic and non-academic settings. Ebenstein et al. (2016) find that an increase in fine particulate pollution1 reduces scores on high-stakes tests in Israel (with a standard deviation increase in fine particulates lowering scores by 1.7% of a standard deviation), while Roth (2021) finds that particulate matter in classrooms reduces the scores of London-area university students. Zhang et al. (2018), examining a nationally representative survey in China, find a statistically significant effect on test scores of verbal ability.

Some evidence also suggests that pollution may not merely dim our mental acuity, but also lead to altered decision-making, sometimes in quite unexpected contexts. Several studies (Huang et al. 2020, Dong et al. 2021, Meyer and Pagel 2017) find that higher air pollution is associated with an increase in behavioural biases among investors and analysts in the financial sector, which appear to be linked to constrained attention and affect alterations. These findings potentially extend to a myriad of high-stakes situations and skilled service professions. Perhaps even more troubling is the possible link between air pollution and criminal activity. Herrnstadt et al. (2021) find that higher particulate matter concentrations lead to increases in violent crime across areas of Chicago (a one standard deviation increase in particulate matter raises violent crime by 2.9%); Burkhardt et al. (2019) estimate that a 10% reduction in daily PM2.5 and ozone in the US could save $1.4 billion in crime costs per year. Across the pond, Bondy et al. (2020) find that increases in the Air Quality Index (a measure of pollution) are associated with increased crime in London.

The effects of air pollution mentioned so far are caused by short-term fluctuations in air quality. But repeated exposure to air pollution can also reduce our capabilities in the longer term through accumulated damages. These consequences may be particularly severe when air pollution is encountered during gestation or early in life, a period of rapid physical development in which the effects of environmental insults are magnified.

One example of such a finding is from Isen et al. (2017), who use the differential impact of the Clean Air Act across different areas to examine the labour market outcomes of children born in more- and less-polluted counties. An increase in birth-year total suspended particles (TSP) by 10 microgrammes per cubic metre (about 1/7 of the then-current EPA air quality standard) was associated with a 1.4% decline in income and a 2.8% decline in the number of quarters employed. Voorheis (2017) and Colmer and Voorheis (2020) link in-utero exposure to TSP with later earnings and college attendance, finding that a 10 microgrammes/m3 increase in TSP is associated with approximately $250 a year in earnings reductions and a decline in college attendance rates of several percentage points. These findings are consistent with other evidence that links in-utero air pollution exposure with reduced academic performance, as measured by standardised test scores (Sanders 2012, Bharadwaj et al. 2017).

As we discuss in a recent overview of the literature (Aguilar-Gomez et al. 2022), great care is needed both when identifying the effects of air pollution (in the sense of determining what part of a correlation represents a causal impact) and when interpreting the resulting estimates. The most convincing evidence in the ‘immediate effects’ literature surmounts problems of sorting (which arises if, for instance, poorer people live or work in more polluted places, which makes it hard to disentangle the effect of poverty form the effect of pollution) and endogeneity (lower output may reduce pollution, even as higher pollution reduces output) by exploiting short-term shocks to exposure that are plausibly unrelated to human choices (such as exposure driven by weather patterns).

Even when we believe the study is well-designed to tell us about a causal connection, we must be careful in interpreting the resulting estimates. People do not stick to prearranged schedules and allow air pollution to take its toll. They may take action to avoid air pollution when they are aware of it (by buying masks and air filters, by running inside on smoggy days); they also take action to deal with its accumulated effects on their body, whether or not they recognise air pollution as the culprit (perhaps by studying harder to compensate for reduced mental acuity). Some of these responses (such as buying air filters or masks) are measured as economic output but should properly be considered as economic costs of pollution; others, such as increased study time, are hard to measure but represent real costs. Estimates in the literature typically correspond to net impacts of these ‘avoidance’ and ‘amelioration’ behaviours; a full accounting of air pollution’s costs must attempt to measure these impacts and add them back in.

The growing concern over exposure to air pollution on the grounds of health is well justified, but there is more to the picture. Further research is needed, especially on air pollution’s cognitive effects and on the costs people incur in trying to avoid or cope with it (Barwick et al. 2020, Khanna et al. 2021). A growing body of evidence suggests that while many people suffer from diseases caused by air pollution, a far greater number may be negatively affected by air pollution even if they never see the inside of a doctor’s office. In our review (Aguilar et al. 2022), we conclude that virtually no aspect of human life is unaffected by the quality of our air. While we propose some future avenues of research and some unanswered questions that will improve policy design, it should be clear that, to a significant degree, we are what we breathe.

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  1. PlutoniumKun

    The good news is that if we take airborne covid seriously, this means proper filtration and ventilation can help with exposure to air pollutants as well as viruses. There really is no excuse (apart from money) for not completely rethinking our approach to indoor ventilation.

    In terms of short term remediation, New Scientist had an excellent article a few years ago (I can’t find it right now, probably behind a paywall) on the use of house plants in offices, and how they can very significantly reduce airborne pollutants. It seems that its not just the number of plants, but also variety matters.

    In China and elsewhere there has been a lot of interest in the compound sulforaphane in helping the body increase the excretion of airborne toxins. The Stanford scientist Jed Fahey has a lot of interesting research on this, if you use his name through the science databases you’ll find some of his papers. Pure sulforaphane is hard to obtain, but its easy to make yourself – just grow broccoli sprouts, pop them in the freezer, and add to a smoothie.

    1. Colonel Smithers

      Thank you, PK.

      Plants are one difference I have noted between offices and even households in the UK and the Germanic part of the continent.

      As you can imagine, office ventilation and plants and their maintenance are often an early and easy casualty of cost cutting.

      I have noticed in the City that older buildings are more likely to be vacant. That may be a health benefit.

      1. PlutoniumKun

        Thinking about it, that New Scientist article is very old – it stuck in my mind because years ago I photocopied it and had it pinned the noticeboard over my desk as a hint to our office managers. Of course, I could have cultivated plenty of my own, but most houseplants die as soon as they see me coming.

        There is no doubt but that many older office buildings are healthier – lots of windows and leaky doors helps ventilation. When I worked in London I hotdesked between a very leaky late 1960’s office building on Tottenham Court Road and an entirely sealed 1980’s office building overlooking Euston Station. The former was extremely noisy and unpleasant in some respects (especially in hot weather) while the latter was blissfully silent and pleasantly cool in the summer, but it was hard not to notice than many staff preferred the older building.

        The huge problem with office ventilation is that its often out of the hands even of management, as so often its outsourced to building managers who will simply respond that the ventilation ‘conforms to all regulations and contract requirements’ when queried. In my experience companies rarely give much attention to the fine detail of maintenance when they sign the lease for an office, so they run into all sorts of trouble when staff complain for one reason or another and they find that they have little to no control over ventilation or similar issues.

        1. Rick Deckard

          I have tried digging into this issue of air cleaning plants myself, and from what I could find online the conclusion I came to is that they are unlikely to have a significant effect on air pollution due to the low throughput rate, compared with mechanical air purifiers with an activated carbon filter.

          With an air purifier, the fan can produce a huge throughput rate, with several air changes per hour at the highest settings. Plants, on the other hand, will act on the air at a far, far slower rate, to the extent that their effect might simply be a drop in the ocean.

          I believe that many of the studies supporting the use of plants for air filtration carried out their experiments in highly controlled, airtight environments with very limited air volume, which obviously does not reflect a real-life home or office.

          I am by no means an expert on this though and come at this very much as a layman. Being a lover of indoor plants, I would love if someone could come along and prove me wrong!

          1. PlutoniumKun

            Its not something I’ve looked into for a while, so I’m sure it may be true that ‘real world’ applications of plants don’t match controlled experiments. But there are other aspects to having plants in a building than the plants ability to clean while respiring – if nothing else, increasing the active surface area in a given space (i.e. the total surface area of the leaves) reduces particulate levels in the air, and particulates are often the vehicles for VOC’s to enter the lung.

          1. Dave in Austin

            I may be the reader. What the Airfree 3000 does is heat a cube of 3″x3″x3″ ceramics to 450 F. There are small vertical holes in the cube through which the heated air passes by convection. Everything carbon that lives and passes through the vertical tubes turns to dust. In a couple of days all the air in an up to 600sq/ft room/space passes through the filter. I’m not sure what I’ve had for 50 years but it is much reduced. Less nasal drip in the morning. Note that certain chemicals and all non-carbon atoms which can suvive the 450 F are unaffected. Put one in the bedroom. Air circulation matter with the Airfree. It either works to some degree or is the finest placebo I’ve found.

            On the “What can people do about pollution” the tradition in the northern hemisphere is “Vote with your feet”. Because of the earth’s rotation and surface heating at the equator, typical surface winds blow from the west to the east and from the north to the south. So living on the north and northwest side of town helps tremendously. London, Berlin, Paris, NY, LA and smaller places like Austin, Tulsa, Chicago and Dallas fit the pattern; the poor live on “the south side” and are “east enders”. Cities that used to slaughter animals and tan hides are the worst. And if you have to live in the middle of a big city move up to the 50th floor. I like spaces with windows on the west and a deck/garden there. Nice place to sit and put plants and the cleaner air comes from that side.. The numbers on lead pollution near highways “before lead and after lead in cars” are staggering.

            The water I drink passes through a Britta water filter. Does it help? Who knows. But as an ex-Catholic I consider it like Holy Water- it can’t hurt.

            And since we do get this type of geographical sorting, I’m wary of the statistics. Are all the bad effects caused by pollution or is some of the effect caused by sucessful people moving to the northwest side of town lowering the rents on the polluted side and leaving that housing to the poor?

          2. PlutoniumKun

            By a coincidence, I was at a friends apartment last night and she had a similar air cleaner as that one for her allergies (she said she ordered it from Korea). She said it works well for her during the main hayfever season. She has two dogs in her apartment but its notably free from any….. doggy odors.

            Its a while back, but there were discussions on this BTL – a few posters at the time seemed quite knowledgeable – on that basis I got one of the basic Ikea air filters (much cheaper than the purpose built ones). Its certainly effective to some degree as the air in my apartment is notably fresher when its on and I’m away for a few days. When I had a room mate who worked in a restaurant I kept it on beside me when reading or working from home and I didn’t get covid when she did back last March.

    2. c_heale

      But that is a massive if in the first sentence. Which governments are really taking airborne Covid seriously. I can’t think of any. The Chinese?

      1. Basil Pesto

        to be honest, China – or at least some localities including Shanghai – don’t seem to be taking very effective airborne measures. poor standard masks (although China’s updated Covid guidelines yesterday stressed important of KN95/N95 minimum), and not much attention paid to air cleaning/ventilation.

        I have seen evidence of some local governments taking air cleaning/ventilation seriously to some extent, but not many governments at bigger scale.

    3. Whobedatguy

      The HEPA filters that work to screen covid also reduce fine particulate matter which is a very nice co-benefit. Unfortunately, toxic organic gases (like formaldehyde, benzene, etc.) are not reduced by HEPA filtration. An activated carbon filter, which is much heavier and more expensive, is needed to filter out toxic organic gases. My wife has chemical sensitivities and finds that scented household/personal care products tend to set her off. I am constantly amazed that most people voluntarily live in a bubble of scents/organic gases, which are finely curated by their cleaners, fabric softeners, and perfumes. Just seems unnecessary and potentially unhealthy to me.

      1. Darius

        Yes. HEPA filters for PM 2.5, a dangerous pollutant for which EPA sets ambient air quality standards. It also filters out airborne viruses, like COVID-19. Activated carbon will will filter chemical pollutants. House plants are nice but I’d have to see evidence they’re effective. They also may harbor mold and give off gases of their own.

  2. Carla

    Huh. “We are what we breathe.” And in June 2022, we are Covid-19. Great article — thanks!

  3. Brian Westva

    Based on the low levels of thinking and productivity in DC, I have to conclude that it has extremely high levels of air pollution. It all makes sense now.

    1. Yves Smith Post author

      I need ones that are almost impossible to kill. But I see poinsettias. Can always buy a big one for the holidays and hope it survives.

      1. CanCyn

        Any of the philodendrons or the dieffenbachias and the snake plant are all pretty easy care.

        1. Dave in Austin

          I’ve never met anyone who was able to kill a snake plant/mother-in-laws tongue by mere neglect. Nice list. I’m keeping a copy.

      2. anon y'mouse

        just don’t have cats and pointsettias.

        i think many traditional house plants are not cat plants.

  4. Mikerw0

    Don’t lose track of the fact that the main agenda of the financial backers of groups like the Federalist Society is dismantling laws that corporations don’t like. My view is that they will effectively gut the Clean Air and Clean Water Acts, and potentially push to unwind the New Deal, through SCOTUS.

  5. The Rev Kev

    Based on recent comments, it looks like air pollution is set to rise because of the NATO/Russia war. There have been those linked articles about Poles burning forest timber as well as coal and in other countries they are starting up coal plants to replace Russian gas and oil. I would not be surprised to see the same happening in America as heating costs really take off. So by the end of this year I would expect to see much more pollution in the air globally which will be reflected in people getting sick and even dying due to the damage of air pollutants.

    1. BeliTsari

      We HAD to sacrifice Ukranians to bail-out Albright’s fracked gas/ oil pyramid (her final grift, along with Ashish K. Jha). We’ve likely unleashed run-away methane release, just by Acela Corridor conversion to fracked gas, but scores-of-thousands of leaky, impossible to plug, quick to kick, re-fracked, abandoned wells were a BIG incentive to bait Putin to do exactly as he’d promised, in 2007? The pollution, just from Shell’s 97mi basically uninspected ethane (cracking) collection system (air, stream, aquifer, crops, livestock) is something NOBODY will discuss. The war is basically a pretext to sell lethal, radioactive, exponentially AGW, inherently uncompetitive fracking (which can NOT be rectified, once begun) to “lower NYC apartment boiler carbon footprints” & save sneering klepocrats’ bridge-fuel investments by making us pay, financially (while COVID/ PASC ravaged, uninsured precariate victims pay with kids’ lives?)

  6. Lex

    I both don’t doubt the results of these studies and cast a wary eye on them. But I would need to read them carefully for a full opinion. “Air pollution” and even particulate concentrations are too broad for me. Size of the PM is important (PM 10, 4, 2.5 and 1) all act differently with the human body; the manner and means of measuring those PM concentrations and their source all affect the outcome. For example, diesel particulate is 2.5 um but it’s not an inert particulate.

    All that said, I still don’t doubt the basic idea of the article and would argue that what we know about air pollution in localized settings is too little. That causes an issue with drawing conclusions but a larger issue with determining effects. That is, the effects may be far worse than we assume, even in these studies, because we’re ignorant. It’s not necessarily difficult to gather local data in depth, it just isn’t done much and gets expensive. EPA has established air monitoring stations, but the data from them is pretty basic. Although they can be used to know when a bunch of PM 1 from forest fires thousands of miles away reach your location and in some cases the ones on the west coast can indicate the level of mercury exposure from Chinese coal plants (mercury is one of the hardest pollutants to get out of coal emissions and requires a final emissions control system that uses chemical catalysts).

    1. chuck roast

      This is a good round-up. Back when I did the Clean Air Act I was concerned with speciation. Basically all we collected at the local level was info on the six criteria pollutants. There is evidence that airborne toxics both individually and in combination have a much greater impact on human health than the criteria. Fortunately, there are asbestos and lead NESHAPs (National Emission Standard for Hazardous Air Pollutants) and they are typically enforced at the state and local level. Ever see an old house undergoing repair and it is completely surrounded by a barrier? Probably your local AQ enforcement guys at work.

      My concern was always mobile source diesel emissions. They can be permitted and controlled as a stationary source but only incidentally as a mobile source. It took EPA years to add diesel smoke to the list of airborne toxics. EPA really does not want, and never wanted to enforce toxic emissions.

      Back to speciation. In the 90’s the EPA did a study to determine the extent of air pollution caused by automotive tire wear. It takes little in the way of imagination to determine that particulate matter from rubber tires would be geographically widespread and the size would be measured in nanometers. The study confirmed this hypothesis and it was quickly buried. I ain’t IMDoc, but I would bet that particulate matter from the wear of rubber tires would not only penetrate deep into the lungs but would be distributed into every part of the body. Add many more microscopic airborne pollutants to this mighty stew, and we have a receipt to cause and assist in the creation of a multitude of illnesses.

  7. jake

    What’s particularly disheartening is that if you look at the monitor readings and satellite assessments of rural, even idyllic areas, the levels of pollution are often just as bad as cities. There’s a powerful correlation with higher temperature, but even in the temperate seasons, it’s true. Compare Manhattan with, say, the area around the Sierra Nevadas in southern Spain, for example. The latter doesn’t come off well.

    And no, notwithstanding the claims of some allergy sufferers, those blasted air filters don’t appear to do much beyond reducing kitchen odors and making noise; no shortage of allergies here to assess. And they won’t sustain subjectively “fresh” air if all the windows are shut. But when the windows are open, the efficiency of the cleaner is of course reduced….. Perhaps there’s no escaping the air.

  8. CanCyn

    “I wish they had provided some advice. Even if the point is to spur collective action, it will take some time for any meaningful concrete action to occur.”
    I feel like this is also true for climate change. And I fear that for both issues that the advice is not forthcoming because of fear that no one wants to act (or perhaps stop/decrease acting so much). People don’t want to give up their cushy lives.

      1. CanCyn

        Indeed, neoliberal BS to the max! Grift, grift, grift. In spite of what I said above, I think there are many who are willing to act given some concrete direction. These topics always make me glad I’m in my early 60s and not my early 20s.

  9. thistlebreath

    Here in the northern end of LA County, a decades-long resistance to a very large mine for Cemex’s operation finally was resolved by a series of “incentives” to get Carlos Slim to relocate way farther out into where nobody lives yet. Central to resistors’ platform was the projected level of “PM10.” Particulate matter 10 microns or smaller. Can’t see it, can’t smell it but it stiffens up everyone’s lung tissue like crazy. Was a long hard fight that just sloughed off the problem to the territories but there was enough money around so that a NIMBY movement succeeded.

    The stuff is evil.

  10. Science Officer Smirnoff

    Alzheimer’s isn’t mentioned* as a fairly recent suspect risk per Guardian coverage in the last couple of years, for example.

    *my very poor vision tonight didn’t encourage search of related terms

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