The Long Beach-Los Angeles area was ranked No. 1 on a list of U.S. cities with the worst air quality in 2018 as wildfires drove major increases in particle pollution, according to an annual report released Tuesday by the American Lung Association.

The 2020 “State of the Air” report, which tracked exposure to unhealthy levels of air pollution from 2016 through 2018, found that California had the most cities with widespread air pollution, with many that experienced their worst-ever periods due to historic wildfires.

But the news isn’t all bad. Residents are now breathing the cleanest air in years as people are following the statewide stay-at-home order to prevent the spread of coronavirus. With fewer people using their cars, the Los Angeles basin has enjoyed its longest period of good air quality days since 1995, according to a UCLA researcher.

While the report does not cover data from 2020, it noted that the impact of air pollution on lung health is a major concern during the coronavirus pandemic.

Overall, the report warns that air quality has become increasingly worse in recent years due to warmer temperatures and wildfires fueled by climate change.

California has two widespread outdoor air pollutants: ozone, also known as smog, and particle, or soot. Both are dangerous to public health and can increase the risk of premature death and serious health issues.

Ozone pollution is exacerbated by rising temperatures. The report notes that 2016, 2017 and 2018 saw historic wildfires and were among the five hottest years on record.

California, despite decades of improvements, still has many of the most ozone-polluted cities.

“Ozone pollution can harm even healthy people, but is particularly dangerous for children, older adults and people with lung diseases like COPD or asthma,” American Lung Association Clean Air Advocacy Director Will Barrett said in a statement. “Breathing ozone-polluted air can trigger asthma attacks in both adults and children with asthma, which can land them in the doctor’s office or the emergency room. Ozone can even shorten people’s lives.”

The American Lung Association urged lawmakers to push for cleaner fuel policies, including zero-emission trucks at California’s ports.

– Cities with worst air quality