According to a newly released report by the American Lung Association, the number of Americans exposed to unhealthy spikes in air pollution has been constantly rising, taking a jump up in the latest observation period of 2018 to 2020. The data shows that most recently, 63.2 million Americans lived in counties where average air quality did not necessarily fail the ALA's standards, but extreme fluctuations in the quality of the ambient air nevertheless took place.
The number of Americans exposed to these spikes rose from 49.6 million in four years, while the number of Americans exposed to unhealthy ozone pollution sank and the number of those suffering from year-round unhealthy air stagnated.
The ALA estimates that in 2018-20, approximately 137 million Americans were exposed to any of these three types of hazardous pollution levels. This is 2 million more than in last year's report, but still far less than the 150 million affected between 2016 and 2018 or the 166 million affected in 2012 to 2014.
Most cities experiencing unhealthy spikes were located in the Western United States, according to the report. Major wildfire and drought activity in the region in recent years contributed to sudden extreme spikes in unhealthy air measurements. Major cities affected by spikes were San Francisco, Sacramento, Los Angeles, Phoenix, Seattle and Salt Lake City. The only Eastern city among the worst 25 for spikes of unhealthy air was Pittsburgh, were industrial pollution continues to pose a problem.