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Skies were thick with smog on this day in 1972 in the Los Angeles suburb of San Gabriel. Photo: EPA/Gene Daniels via the National Archives

12 Urgent Reasons to Reduce Air Pollution

Global warming gets all the attention, but bad air is deceptively deadly and damaging to kids and adults

Robert Roy Britt
Nov 11, 2020 · 8 min read

Air pollution generated by fossil-fuel burning is often portrayed as a mere nuisance, a sideshow to the threat of global warming, a visible haze over a cityscape that sometimes drives the most vulnerable people indoors. In many ways, Americans have gotten used to bad air — we go about our business, our worries dominated by other important issues like climate change, Covid-19 and political polarization, with many people now pinning hopes on President-elect Joe Biden to tackle all three.

But the truth about polluted air is much darker and more urgent, the effects far more sinister and widespread than you might realize. Let’s do a quick science-based inventory of the issues. Dirty air…

  1. Kills infants

Yes, air pollution is on the rise again after decades of improving air quality. About 43% of U.S. residents today live in counties with unhealthy pollution levels.

Already, toxins and particles we pump skyward kill more than 100,000 people in the United States every year, according to a study in the Proceedings of the National Academy of Sciences. Several separate recent studies have revealed a host of deadly and debilitating effects of air pollution across all age groups. A study of data on 4.5 million U.S. veterans found air pollution contributes to premature deaths from a wide array of causes, including heart attacks, stroke, kidney disease, dementia, type 2 diabetes, lung cancer and pneumonia.

Globally, air pollution causes one in 10 deaths of children under age five, according to the World Health Organization.

Contributing to Covid deaths

A new study of county-level air pollution across the United States finds that historical exposure to modestly higher levels of fine particulate matter—tiny bits of soot that penetrate deep into human lungs—is associated with an 11% increase in COVID-19 death rates.

“If we take two geographical areas that are very similar to each other with respect to all of the potential characteristics… the more polluted area will experience a higher level of Covid-19 mortality,” says study team member Francesca Dominici, PhD, a professor of biostatistics, population, and data science at the Harvard T.H. Chan School of Public Health.

The finding, published Nov. 4 in the journal Science Advances, confirms separate research earlier this year that found people who live in the most polluted parts of America are more likely to be infected by the coronavirus and more apt to suffer severe symptoms and die from Covid-19.

Scientists are not surprised by these discoveries, since air pollution was already known to exacerbate the impact of other respiratory infections like the flu, among adults and children.

Children are suffering and dying

The unhealthy effects of air pollution are cumulative and are particularly devastating for children who grow up with it. If they grow up.

Air pollution has been linked to low birth rates, more preterm births, and higher rates of infant deaths in the United States and globally.

The effects of air pollution can be difficult to sort out from other factors, however. For one thing, children living in highly polluted areas are more likely to be affected by stresses related to poverty and other systemic disadvantages. Earlier this year, scientists determined that prenatal exposure to hydrocarbon-based air pollutants plus childhood stress combine to heighten attention and cognitive problems.

“Air pollutants are common in our environment, particularly in cities, and given socioeconomic inequities and environmental injustice, children growing up in disadvantaged circumstances are more likely to experience both life stress and exposure to neurotoxic chemicals,” says study team member Amy Margolis, PhD, an assistant professor of medical psychology in psychiatry at Columbia Psychiatry. The findings are published in the Journal of Child Psychology and Psychiatry.

Extensive research by other institutions finds a clear link between air pollution and asthma in children, particularly those 11 and younger, and especially among lower-income and minority populations.

Links to autism and brain development

Air pollution includes carbon monoxide, nitrogen dioxide, ozone and sulfur dioxide, with particular attention paid to fine particulate matter, tiny grains like dust easily penetrate into the lungs and disrupt respiratory function. These particles, referred to as PM2.5, are less than 2.5 microns in diameter. For comparison, if a human hair were a capital “O” on this page, a bit of PM2.5 would be about the size of the period at the end of this sentence.

When the 24-hour concentration of PM2.5 is above 35 micrograms per cubic meter (μg/m3), it’s considered unhealthy by the Environmental Protection Agency. An annual average level above 12 μg/m3 is likewise deemed unhealthy.

Each increase of 10 μg/m3 in the daily average of small particulate matter brings a 20% increased risk of schizophrenia to children, according to a study in the journal JAMA Network Open. Children exposed to an average daily level above 25 μg/m3 are at 60% greater risk of developing schizophrenia compared to kids exposed to less than 10 μg/m3.

Other research has linked air pollution to an increased risk of childhood autism, as well as slower cognitive development.

A 2018 study determined that children ages 6 to 10 who were exposed to high levels of air pollution while in the womb are more likely to have brain abnormalities, including a thinner outer layer, which could contribute to the known issues of impaired cognitive function, the researchers wrote in the journal Biological Psychiatry.

“Air pollution is so obviously bad for lungs, heart, and other organs that most of us have never considered its effects on the developing brain,” the journal’s editor, John Krystal, MD, said in a statement. “But perhaps we should have learned from studies of maternal smoking that inhaling toxins may have lasting effects on cognitive development.”

No age limit on misery

Air pollution can also diminish the quality of later life for those who might not suffer noticable effects early on.

For each 5 μg/m3 increase in average annual levels of fine particulate matter, older people on Medicare face a 13% higher risk of a first-time hospital admission for Parkinson’s disease, Alzheimer’s disease or other neurological conditions, according to a study last month in the journal Lancet Planetary Health. The equation for increased risk with increased pollution levels held true even for exposures below the EPA threshold considered safe.

The research involved 17 years of data on 63 million older U.S. adults, considering pollution concentration by zip codes and accounting for potentially confounding factors like socioeconomic status.

“Our study builds on the small but emerging evidence base indicating that long-term PM2.5 exposures are linked to an increased risk of neurological health deterioration, even at PM2.5 concentrations well below the current national standards,” says study co-leader Xiao Wu, a doctoral student in biostatistics at Harvard Chan School’s Department of Environmental Health.

“Current standards are not protecting the aging American population enough, highlighting the need for stricter standards and policies that help further reduce PM2.5 concentrations and improve air quality overall,” says Harvard’s Antonella Zanobetti, PhD, a specialist in the effects of air pollution on health and Wu’s co-author.

Wu and colleagues examined similar data earlier this year to estimate the extent to which lives of older Americans are cut short by fine particulate matter exposure. Their conclusion: “If the U.S. lowered its annual standard to from 12 μg/m3 to 10 μg/m3 — which is the guideline set by the World Health Organization — 143,257 U.S. lives could be saved over 10 years.

Bad air has other ill effects shy of death and physical illness. In a review of 178 studies earlier this year, researchers concluded that air pollution is linked to more depression, less happiness, poorer decision making and reduced worker productivity.

“Physiologically, exposure to air pollutants can trigger anxiety by increasing oxidative stress and systemic inflammation,” says Professor Jackson Lu, an MIT Sloan School of Management researcher and leader of the study. “Psychologically, the experience of air pollution can trigger existential anxiety about one’s health and future.”

Reversing positive trends

All these findings come as air pollution in the United States is rising again, after decades of decline owing to rules enacted under the Clean Air Act of 1963. But over the past four years, the Trump administration has relaxed emission regulations and rolled back standards on everything from coal-fired power plants to gas-mileage standards and light bulb efficiency. Thanks at least in part to these reversals:

  • In metro areas, the number of days “unhealthy for sensitive groups” was 15% higher in 2018 than the annual average from 2013 to 2016.

The effects are particularly devastating to lower-income areas with large minority populations, where heavily polluting factories are concentrated. That creates a disproportionate effect on people of color, who already deal with systemic causes of poor health and less access to quality healthcare.

“Even absent the pandemic, rolling back regulations will have a detrimental effect to public health,” Dominici told me earlier this year, when the initial research suggested air pollution was exacerbating Covid-19 infections and deaths. “And now with a pandemic that we know affects our lungs, this is an irresponsible act” that will “further increase health and environmental injustice.”

Biden has promised to rejoin the Paris Agreement on climate change and to reverse many of Trump’s regulatory actions that invite pollution and threaten to release more greenhouse gases, all in an effort to improve the odds of avoiding an irreversible tipping point in global warming that would be disastrous to life, health and economies around the globe.

But some in politics and industry fear these changes could hurt the already beleaguered U.S. economy. Science and history suggest otherwise.

Serious upside potential

Clearing the air would be better for human health but also good for the economy, as I reported earlier this year, even without taking into account possible job creation in renewable energy sectors.

“Fewer premature deaths and illnesses means Americans experience longer lives, better quality of life, lower medical expenses, fewer school absences, and better worker productivity,” the EPA states. The dollar benefits of the Clean Air Act, according to the agency’s most recent analysis, were expected to exceed its costs by more than 30-to-1 this year.

More immediately, cleaner air means fewer dead babies, less childhood disease, longer lives for the entire population on average, and improved physical and mental well-being along the way.


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Robert Roy Britt

Written by

Explainer of things, independent health and science journalist, author, former editor-in-chief of LiveScience and Space dot com.



Health and wellness news and information about the human body and mind, the world around us, and our place in it.

Robert Roy Britt

Written by

Explainer of things, independent health and science journalist, author, former editor-in-chief of LiveScience and Space dot com.



Health and wellness news and information about the human body and mind, the world around us, and our place in it.

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