The 21st annual "State of the Air" report analyzed data from 2016, 2017 and 2018 -- three of the five hottest years in recorded history in the world, the report said.
Those warmer temperatures contributed to the rise of ozone levels in many places in the US, the report found, affecting more than 137 million people. Breathing in ozone, or smog, can cause asthma attacks, shortness of breath, and trigger coughing, the report said.
The heat from increasing climate change also contributed to wildfires, especially in western states, which spiked particulate pollution levels to dangerous levels, the report said.
Particulate matter is a mixture of solid and liquid matter found in the air. Dust, dirt and smoke particles are larger but there are also extremely small, inhalable particulates that can't be seen with the naked eye. Those are called PM 2.5 because their size is generally 2.5 micrometers or less.
That's really tiny. As a comparison, an average human hair is 30 times larger than a PM 2.5 particle. Because they are so small, these particulates can get deep into our airways and wreak havoc with our lungs and bodily functions.
The report found nine western cities reached their worst levels of particulate pollution ever recorded: Fairbanks, Alaska; Yakima, Washington; Las Vegas, Nevada; Phoenix, Arizona; Spokane, Washington; and the following cities in California -- Chico, Salinas, Redding and Santa Maria.
In contrast, the cities with the cleanest air, defined as no high ozone or high particle pollution days over the three-year period of the sudy, were Bangor, Maine; Honolulu, Hawaii; Wilmington, North Carolina; and Burlington, Vermont.
"The report finds the air quality in some communities has improved, but the 'State of the Air' finds that far too many people are still breathing unhealthy air," said American Lung Association President and CEO Harold Wimmer in a statement.
"Climate change continues to degrade air quality and increase the risk of air pollution harming health," Wimmer said.
Significant health impacts
Even short-term exposure to particulate pollution can trigger cardiovascular issues, strokes and asthma attacks as well as contribute to the development of dementia, studies show.
Air pollution is also increasing the risk of dying from Covid-19, the disease caused by the novel coronavirus. A recent Harvard study found US counties with the highest levels of air pollution had significantly higher death rates from COVID-19 than counties with much lower levels.
Seib lives in the Harlem district of New York City, which has been extremely hard hit by Covid-19. He caught a milder form of the virus a few weeks ago, and even that was frightening for him.