The U.S. Cities With the Most Deaths From Air Pollution (4 of the top 5 in California)

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.