LOS ANGELES, CALIFORNIA - JUNE 11: Smog hangs over the city on a day rated as having 'moderate' air quality in downtown Los Angeles, on June 11, 2019 in Los Angeles, California. According to the American Lung Association's annual "State of the Air" report, released in April and covering the years 2015-2017, Los Angeles holds the worst air pollution in the nation. The city has had the worst smog, otherwise known as ground-level ozone, in the U.S. for 19 of the past 20 years. (Photo by Mario Tama/Getty Images)
