A smoggy day in Los Angeles. Photo : Getty Images

Decreasing levels of air pollution in the U.S. have led to fewer deaths and illnesses, according to a new report out this week. But there are pockets of the country, namely Los Angeles, where air pollution kills thousands of people, and, frighteningly, the Trump administration is poised to reverse the progress against pollution made in recent years.




The report is the result of an ongoing collaboration between the American Thoracic Society and New York University’s Marron Institute for Urban Management, as part of their “Health of the Air” initiative.

Relying on air quality data from hundreds of counties throughout the U.S., the report focuses on two types of air pollution: pollution caused by tiny bits of particulate matter (PM 2.5) and ozone, the gas that’s made up of three oxygen molecules. High up in the atmosphere, naturally produced ozone shields us from the Sun’s radiation, but ground-level ozone produced by industrialization can damage our lungs.


The report estimates the annual number of deaths, serious illnesses (such as asthma attacks), and missed days of work and school caused by either type of pollution from 2008 to 2017. It uses data from past epidemiology studies and the Environmental Protection Agency to roughly estimate how much more likely people are to develop pollution-related and potentially fatal conditions like heart attacks, lung cancer, and severe asthma attacks, given the average amount of air pollution where they live.

Four of the five cities with the most pollution-related deaths in 2017 were in California, with the Los Angeles metropolitan area (covering Los Angeles, Long Beach, and Glendale ) continuing to hold onto the top rank since 2010. In 2017, LA had an estimated 1,322 extra deaths from air pollution. Pittsburgh, Pennsylvania was the sole non-California city in the top five, with 232 pollution-related deaths that year; while the NYC metropolitan area was sixth, with 188 estimated deaths caused by pollution.

Here are the top 10 cities in the report, with the number of estimated deaths caused by air pollution in 2017:

Los Angeles-Long Beach-Glendale, California (1,322) Riverside-San Bernardino-Ontario, California (940)

Bakersfield, California (293) Pittsburgh, Pennsylvania (232) Fresno, California (225) New York-Jersey City-White Plains, New York-New Jersey (188) Phoenix-Mesa- Scottsdale, Arizona (152) Visalia-Porterville, California (131) Cleveland-Elyria, Ohio (116) Chicago-Naperville-Arlington Heights, Illinois (122)

Overall, though, Americans’ lungs have been getting less and less clogged by pollution. In 2017, the report found, there were an estimated 7,140 more deaths from air pollution in the U.S., compared to 12,600 deaths in 2010. Sick days and cases of serious illness declined as well. And the report also found the number of areas with overall air pollution levels higher than the guidelines established by the American Thoracic Society (which are stricter than those established by the Environmental Protection Agency) shrank over time, too. The report also comes fresh off the heels of another study published this week that found fewer kids in California developed asthma as levels of air pollution started dropping in the 1990s.


But despite this good news, the authors of the current report say there are some worrying trends. The rate of declining PM 2.5 has started to level off in recent years, while levels of ozone have barely budged at all. And thanks to attempts by the current Trump administration to weaken regulations created by the Clean Air Act, the principal piece of legislation responsible for reducing air pollution in the U.S. since its passing in 1963, this progress could be even further threatened.

“The proposed roll back of several Clean Air Act regulations and the proposed roll back of the greenhouse gas standard for automobiles will make it hard for communities to maintain their air quality, and even harder for cities with poor air quality to clean up,” said co-author Gary Ewart, chief of ATS advocacy and government relations, in a release issued by the American Thoracic Society.


In addition to these rollbacks, the Trump-era EPA has gone after fewer criminal polluters than in past years, done next to nothing to clean up lead in water, and formed a rule that encourages the use of coal energy, which will likely lead to more air pollution. Just this week, the New York Times reported that the EPA is also planning to abandon its current formula for estimating pollution-related deaths, following its own report showing that the new coal rule would cause more than a thousand extra deaths a year.