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New research from the American Lung Association reveals which parts of the U. S. have the most polluted air.




In their 21st annual “State of the Air” report for 2020, released Tuesday, the group examined federal data on the two most widespread types of air pollution to create a comprehensive overview of toxic air across the country. The re port found that that cities in the W est, especially in California, face a disproportionate amount of health-harming emissions and that half of Americans are breathing dangerous air.

The report examined Environmental Protection Agency data from 2016 to 2018 for ozone and particulate matter. The former is linked with cars, power plants, petrochemical facilities, and other activities while the latter is found in wildfire smoke as well as industrial activities from power plants to construction . These pollutants can cause a variety of respiratory and pulmonary issues, strokes, and other health problems.


The five localities with the highest concentrations of ozone are all in California: the Los Angeles and Long Beach area, Visalia, Bakersfield, the Fresno-Madera metropolitan area, and Sacramento and its surrounding communities. The top five cities for long-term exposure to particulate matter were also all in California, with Bakersfield, Fresno-Madera, Visalia, the Los Angeles area, and the San Francisco area topping the list.

That may be surprising, since California is known as an environmental leader when compared with other states. But a key reason for the increase in air pollution was climate-change-fueled wildfires. During those years, California saw massive fires across the state due to hot, dry conditions , with 2018 standing out as the state’s most destructive wildfire season on record.

California has it particularly bad when it comes to air pollution , but it’s not alone. The report shows that 150 million Americans—nearly half the population—live in counties with dangerously high levels of ozone or particulate matter. While the report doesn’t contain all bad news, there’s still clearly a lot of work to be done.


“The report finds the air quality in some communities has improved, but the ‘State of the Air’ finds that far too many people are still breathing unhealthy air,” said American Lung Association President and CEO Harold Wimmer in a statement.

The 2020 version of the report shows an increase in exposure to air pollution from the last report, which found that 141 million Americans lived with unhealthy pollution levels from 2015 to 2017. The current report looks at data from 2016 to 2018. Not everything is getting worse: the shuttering of coal-fired power plants has led to cleaner air in the South and East. But pollution has increased due to other causes, including the climate crisis.


In addition to contributing to worse and more frequent wildfires, warmer temperatures are causing higher levels of ozone and particulate matter in the atmosphere. The years the report looked at are among the hottest on record, including 2016, the current record holder.

While this is the 21st iteration of the report, it marks an even more important milestone: the 50th anniversary of the Clean Air Act. Those regulations have helped clean up air pollution. Since the law was passed in 1970, the nation has cut air pollution by 70 percent. But today, under the Trump administration, those regulations—and the climate—are under attack. Previous research shows that pollution has started rising under the Trump administration for the first time in a decade.




“The science is clear: the nation needs stronger limits on ozone and particle pollution to safeguard health, especially for children and people with lung disease,” Wimmer said.

That’s perhaps especially true right now, as the country is in the throes of a respiratory virus pandemic. Recent studies show that exposure to polluted air makes people more like to succumb to covid-19. While the pandemic has led to a drop in air pollution in many locations, it’s going to require hard work to make sure pollution levels don’t spike.