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Smog hangs over Louisville and the Ohio River in September 1972. Photo: EPA/William Strode via the National Archives

Air Pollution’s Comeback is Double Trouble, Especially for Children

On the rise again, bad air is deadlier and more debilitating than we thought. And that’s just the half of it.

Robert Roy Britt
Jan 27, 2020 · 13 min read

When Dr. Matthew Fuller, an assistant professor of surgery at University of Utah Health, noticed “a pattern in the relation to air quality and pregnancy loss” among women living on the Wasatch Front, a region known for atrocious smog days, he teamed up with research analyst Claire Leiser to dig into data on more than 1,300 women who had come into the emergency department after a miscarriage. Their research, published in the journal Fertility and Sterility, found that women had at 16% higher risk of miscarriage following short-term exposure to elevated levels of air pollution. It is one of many studies revealing that the effects of air pollution start in the womb, changing the biology of the unborn and dogging many of them through childhood, if they make it there.

Global warming gets all the attention, but one of the primary causes of climate change — burning fossil fuels — pollutes the air we breathe, too. Yet like a foul-smelling zombie, pollution is creeping back in the United States, just as the federal government has rolled back more than a dozen clean-air policies, some of which were enacted in recent decades and others that date back to the hazy days of the 1970s.

The resurgence also comes amid a host of new and recent studies revealing that air pollution raises the risk of asthma, altered brain structure and behavioral problems in children, heart attacks and strokes in adults, and that it fuels anxiety and depression along the way. Ultimately, dirty air is thought to kill more than 100,000 people in the United States every year, according to a study last year in the Proceedings of the National Academy of Sciences, and some 7 million around the globe.

More on the latest health findings below. But first, a fact that might surprise some people:

Clean air is good for the economy

Air pollution consists, in part, of small particles of soot generated by burning gas, oil, coal and other fossil fuels, along with smoke and dust from fires, and even dust kicked up by automobiles, literally where the rubber meets the road. Particulate matter, as it’s called, is particularly detrimental to health, studies show. Smog, a derivative of fossil-fuel emissions, develops when polluting gases interact with sunlight in the lower atmosphere, creating ozone, which is highly toxic at ground level (naturally occurring ozone in the stratosphere is good, protecting life on Earth from excessive ultraviolet radiation). Then you’ve got good ol’ gaseous emissions like carbon monoxide that have their own negative health effects.

Efforts to clear the air are good for jobs and economic growth, according to the Environmental Protection Agency, which is charged with keeping the air and water clean (and, ironically, is involved in some of the recent regulation rollbacks).

“Between 1970 and 2017, the combined emissions of the six common pollutants [carbon monoxide, sulfur dioxide, nitrogen oxides, volatile organic compounds, fine particulate matter and lead] dropped by 73 percent,” the EPA says. “This progress occurred while the U.S. economy continued to grow, Americans drove more miles and population and energy use increased.”

The agency lauds the effects of the Clean Air Act: “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’s research on the Clean Air Act finds that the dollar benefits, by 2020, will exceed the costs by more than 30-to-1.

Separately, a new study in the journal American Economic Review estimates that the reduction in fine-particle air pollution between 1999 and 2013 led to annual savings that reached $25.5 billion in 2013, by lowering health care costs—including things like emergency room visits, hospitalizations and other patient spending—and lowering mortality (each “life year” lost was assigned a “value” of $100,000, a common estimate used in economic research). The savings are a low estimate, the researchers say, for three reasons: They’re based only on older people who are enrolled in Medicare; they consider only the effects of particle pollution, not all air pollution; and they considered only acute, event-driven exposure, not chronic exposure to air pollution over the years.

Even so, the costs required to reduce particle pollution represent a bargain, says study team member Julian Reif, an assistant professor of finance and economics at the University of Illinois.

“We estimate that mortality costs of air pollution for the elderly alone are close to the EPA’s estimated costs of meeting air pollution standards,” Reif tells me. “After one accounts for effects on younger populations as well as on quality of life, our results suggest that the costs of lowering air pollution are less than the benefits.”

The resurgence

Despite the good news, all based on data now a few years old, pollution is making a comeback.

The average amount of particulate matter rose 5.5% from 2016 to 2018, according to a report from the National Bureau of Economic Research. The reversal likely owes to “increases in economic activity, increases in wildfires, and decreases in Clean Air Act enforcement actions,” the report’s authors stated, adding that the increase contributed to an additional 9,700 premature deaths in 2018 alone.

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Image: EPA

“The uptick is not large, but it does signal the potential reversal of a long-run trend where particulates were declining,” says Tatyana Deryugina, an assistant professor of finance at the University of Illinois and co-author with Reif of the new study on pollution costs.

Meanwhile, after mostly falling for decades, the number of bad air days that are “unhealthy for sensitive groups” in metro areas across the country was 15% higher in 2018 than the annual average from 2013 to 2016. Some 43% of U.S. residents now live in counties that have unhealthy levels of pollution, the American Lung Association reports.

Some of the most toxic air exists in cities, near industrial centers and in areas of high vehicle traffic. But pollution travels with the wind, and it’s not always generated by the sources you think of.

In a new study looking at how specific events can have effects hundreds of miles away, small particulate matter from wildfires in Canada and the U.S. Southwest were found to cause “significant increases in pollution concentrations” in New York City days later. The findings were published Jan. 21 in the journal Atmospheric Chemistry and Physics.

On an ongoing basis, sulfur and nitrogen oxides generated by industrial pollution are altering ecosystems in high-mountain lakes and other remote areas, according to the National Park Service. Pollution does not have to be visible to be harmful, the EPA says. Even “very low levels” can be bad for public health, the agency says.

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Pollutants from faraway sources—even from other countries—creates haze and negative biological effects in remote desert and mountain regions. Image: National Park Service

Known health effects

Here is a sampling of the EPA’s well-understood concerns about just some of the pollutants that foul the air:

  • Ozone “reduces lung function and causes respiratory symptoms, such as coughing and shortness of breath. Ozone exposure also aggravates asthma and lung diseases such as emphysema.”
  • Particulate matter, tiny bits of dust and smoke that can penetrate deep into the lungs and into the bloodstream, “can cause harmful effects on the cardiovascular system including heart attacks and strokes.”
  • Carbon monoxide “reduces the amount of oxygen reaching the body’s organs and tissues. For those with heart disease, this can result in chest pain and other symptoms.

A new review of 178 studies finds air pollution linked to increased depression and decreased happiness, poorer decision making, reductions in worker productivity and increased criminal activity.

“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, published in January 2020 in the journal Current Opinion in Psychology. “Psychologically, the experience of air pollution can trigger existential anxiety about one’s health and future.”

(Based on other human and animal studies, air pollution has been found to increase inflammation in body tissues, a sign that the immune system working overtime, and to increase oxidative stress, an imbalance in the body’s free radicals and antioxidants.)

Lu’s new review finds “a vast body of research” in the United States, Canada, Europe, China and elsewhere showing that air pollution negatively affects human health and well-being and is bad for cognitive functioning “from prenatal development, to childhood, to young adulthood, and even into old age.”

As one example, Lu found cites a 2017 study finding baseball umpires are more likely to make bad calls when the air is thick with pollutants. In another, investors make poorer decisions when pollution is high. More people miss work when the air is polluted, the review found, and one study of data from 9,360 U.S. cities linked bad air to increases in murder, rape, robbery, assault and theft.

Depression, suicide & dementia risks

Another review, published last month in the journal Environmental Health Perspectives, links air pollution to an increased risk of depression and suicide. The findings were based on data from 16 countries and 25 studies.

“We already know that air pollution is bad for people’s health, with numerous physical health risks ranging from heart and lung disease to stroke and a higher risk of dementia,” says the study’s lead author, Isobel Braithwaite, a climate and health researcher at University College London. “Here, we’re showing that air pollution could be causing substantial harm to our mental health as well, making the case for cleaning up the air we breathe even more urgent.”

The research doesn’t prove air pollution directly causes bad mental health, but the researchers say there is evidence to suggest cause-and-effect.

“We know that the finest particulates from dirty air can reach the brain via both the bloodstream and the nose, and air pollution has been implicated in increased neuroinflammation, damage to nerve cells and to changes in stress hormone production, which have been linked to poor mental health,” Braithwaite says.

Other recent findings:

  • Air pollution is linked to reduced bone mass. Again, cause-and-effect isn’t proven, but “inhalation of polluting particles could lead to bone mass loss through the oxidative stress and inflammation caused by air pollution,” says Otavio Ranzani, first author on the research paper, published Jan. 3 in the journal Jama Network Open.
  • Higher levels of air pollution are linked to higher rates of death from cardiovascular and respiratory diseases, according to a study last year in the New England Journal of Medicine.
  • Even teenage behavior has been linked to breathing bad air over time. A 2017 study in the Journal of Abnormal Child Psychology followed 682 children in the greater Los Angeles area for nine years, starting at age nine. They tracked pollution levels around each child’s home and used questionnaires with parents to track the kids’ behavior. The result: Initial and cumulative exposure to pollution was “significantly associated… with increased delinquent behavior.”

“It is widely recognized that ambient air pollution is detrimental to the respiratory and cardiovascular health of young and old alike,” says Jiu-Chiuan Chen, an associate professor of preventive medicine at the Keck School of Medicine and senior author of the teen study. “But in recent years, scientists have come to acknowledge the negative impact of air pollution on human brains and behaviors.”

Rolling back the rules

The latest health findings come as the Trump administration works to reverse a half-century of efforts to clean what had been utterly filthy air, an undertaking rooted in amendments signed in 1970 by Richard Nixon that gave teeth to the 1963 Clean Air Act, and the creation of the EPA that same year by Nixon’s executive order.

In 2017, Trump issued his own executive order, stating that “the heads of agencies shall review all existing regulations, orders, guidance documents, policies, and any other similar agency actions (collectively, agency actions) that potentially burden the development or use of domestically produced energy resources, with particular attention to oil, natural gas, coal, and nuclear energy resources.”

Among the regulatory rollbacks now underway are three that are typically framed by opponents as bad for the climate, but which also would cause increases in particulate matter and other pollutants that kill people now:

Gas mileage standards: The current average for all cars and trucks is 29 mph, with regulations that would improve it to 37.5 mph by 2025. The Trump administration’s plan, in an effort to stimulate job growth and reduce the cost of vehicles, would instead raise it to 31.8 mph by 2026, according to an analysis by Consumer Reports. “Fuel economy and vehicle emissions standards are one of the most powerful tools we have to save consumers money and reduce air pollution,” says Shannon Baker-Branstetter, Consumer Reports’ manager of cars and energy policy.

Light bulbs: The Department of Energy (DOE) plans to not enforce new standards for light bulb efficiency which, over the past dozen years since being introduced by President George W. Bush, have spurred industry to develop LED lighting that saves consumers money, uses less energy, and comes in increasingly pleasing warm tones that render that old office lighting glaringly obsolete. Switching to new Energy Star light bulbs from incandescent bulbs — which have changed little since Thomas Edison commercialized them 141 years ago — can save the average consumer $75 per year and use anywhere from 25% to 80% less energy, the DOE says. And they last up to 25 times longer.

Coal: The EPA aims to loosen requirements for coal power plants in how they dispose of and store coal ash, the leftovers that can contain arsenic, mercury and other heavy metals. Other rule changes are being contemplated to help coal companies remain competitive at a time when many electrical utilities are turning to other sources for power generation, from natural gas to wind and solar.

In all, the Trump administration is working to ease or eliminate 95 environmental rules, including 25 related to air pollution and emissions, according to a New York Times analysis. Of those, 58 have been completed, including 16 related to air pollution and emissions.

Health and environmental experts are sounding alarm bells about the reversals.

“Rather than seeking to simply return to some kind of pre-Obama baseline, the administration appears to be pursuing a more ambitious agenda: to neutralize the Clean Air Act as a mechanism for greenhouse gas (GHG) regulation,” Kyle Danish and Sarah Ladislaw write in a commentary for the Center for Strategic & International Studies. And that worries officials at the American Lung Association: “The Clean Air Act must remain intact and enforced to enable the nation to continue to protect all Americans from the dangers of air pollution,” the agency writes in its State of the Air 2019 report.

“At a time when the US and governments around the world are making important policy decisions regarding the future of the air we breathe, they need to bear in mind not only the physiological and environmental costs of air pollution, but also its psychological, economic, and societal costs,” says Lu, the MIT researcher. “Air pollution corrupts not only the health of individuals, but also the health of society.”

Meanwhile, UN Secretary-General António Guterres points out that battling air pollution “presents a double opportunity, as there are many successful initiatives that both clear the air and reduce greenhouse gas emissions, such as phasing out coal-fired power plants and promoting less polluting industry, transport and domestic fuels.”

Consider the unborn

Air pollution disproportionately affects the elderly, people with respiratory illnesses, and children who, according to the World Health Organization, breathe more rapidly than adults and absorb more toxins. About 600,000 children around the world die every year from the effects of air pollution, the organization states. “Polluted air is poisoning millions of children and ruining their lives,” says WHO Director-General Tedros Adhanom Ghebreyesus.

Even the unborn are put at risk, a fact that researchers have known for decades but which of late has come into sharper focus.

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Pollution nowadays in the Salt Lake City area. Image: University of Utah Health

A study last year found when pregnant women are exposed to high levels of air pollution in the week prior to giving birth, their infants are more likely to end up in intensive care in the first week of life. The chances increase, depending on the type of pollution, anywhere from 4% for carbon monoxide to as high as 147% for organic compounds, the researchers conclude in the Annals of Epidemiology. Citing previous studies, the researchers say that when a pregnant woman is exposed to air pollution, the risk rises for gestational diabetes, preeclampsia, preterm birth and lower birth weight.

The researchers aren’t sure what causes the problems, but they suspect pollutants increase inflammation, restricting blood vessel growth in the placenta, robbing a fetus of oxygen and nutrients. In fact, a separate study in 2016 found that breathing even low levels of fine-particle pollution has a negative impact on a pregnant woman’s placenta and up the odds of premature birth and “lifelong developmental problems.”

Exposure to air pollution in the womb is also linked to thinner outer layers of the brain in childhood and less ability to regulate self-control over temptations and impulsive behavior, researchers reported in the journal Biological Psychiatry.

In 2018, researchers at Columbia University’s Center for Children’s Environmental Health reviewed 205 studies on air pollution childhood health. The upshot: “The direct health impacts in children of air pollution from fossil fuel combustion include adverse birth outcomes, impairment of cognitive and behavioral development, respiratory illness, and potentially childhood cancer.”

The message from scientists who study the deadly effects of air pollution is clear.

“Policies to reduce fossil fuel emissions serve a dual purpose, both reducing air pollution and mitigating climate change, with sizable combined health and economic benefits,” said the Columbia center’s director and study lead author Frederica Perera, PhD. “However, because only a few adverse outcomes in children have been considered, policymakers and the public have not yet seen the extent of the potential benefits of clean air and climate change policies, particularly for children.”

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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


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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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