Forty-one percent of Americans are breathing unhealthy air. According to the American Lung Association's State of the Air 2021 report (http://www.lung.org/research/sota), 41% of Americans-more than 135 million people-live in places with unhealthy air. Each year, the association collects air quality data to assess ozone levels, short-term particle pollution, and year-round particle pollution over the prior three years (this year's report includes data from 2017-2019). Though there was a slight improvement in the number of people exposed to unhealthy air from the last report, particle matter pollution worsened again this year. This is a worrisome trend as particle pollution is increasingly recognized as especially dangerous; research indicates it is likely responsible for tens of thousands of premature deaths in the United States each year. Wildfires, with the smoke's mix of particulate matter, gases, and air toxins, represent a growing source of particle pollution.