Boulder County Air Quality Report: U.S. Monitoring Grades

BOULDER COUNTY — Residents in Boulder County are among the more than 40 percent of Americans living in an area with unhealthy levels of ozone or particle pollution, according to the American Lung Association’s new 2021 “State of the Air” report.

The report gave out three air quality grades — one each for annual and short-term particle pollution, and another for ozone pollution.

In Boulder County, the report issued an “F” grade for ozone, a “C” grade for 24-hour particle pollution and a pass for the annual particle pollution test.

The association published a list of the worst counties in the nation for high ozone days, and both Jefferson and Douglas counties were ranked No. 12 and No. 22, respectively.

Metro Denver is the 8th worst metro area in the nation for high ozone days, according to the report

In Denver, the report issued a “D” grade for ozone, a “C” grade for 24-hour particle pollution and a pass for the annual particle pollution test.

Here's a look at the grades in some metro Denver counties:

Arapahoe County

• Ozone: F
• 24-hour particle pollution: B
• Pollution test: Pass

Adams County

• Ozone: B
• 24-hour particle pollution: C
• Pollution test: Pass

Douglas County

• Ozone: F
• 24-hour particle pollution: C
• Pollution test: Pass

Jefferson County

• Ozone: F
• 24-hour particle pollution: No monitor exists
• Pollution test: No monitor exists

The lung association collected the air quality data at official monitoring sites operated by federal, state, local and tribal governments.

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Nationally, the report, which looked at data from 2017-2019, found that more than 135 million Americans — about 41.1 percent of the country — are living in places with unhealthy levels of ozone or particle pollution.

There’s been some progress since the release of last year’s report, the lung association found, as 14.8 million fewer people are living in areas with unhealthy air. That is mostly attributed to reduced levels of ozone pollution, according to the report.

Ozone pollution, often called smog, forms when gases that come out of tailpipes and smokestacks, among other sources, come into contact with sunlight, according to the lung association. It is “one of the most dangerous and widespread pollutants in the U.S.,” the lung association said.

Particle pollution, the lung association said, is a mix of tiny solid and liquid particles in the air.

The three years included in the report released Wednesday are ranked among the six hottest years on the record globally. The American Lung Association has issued its “State of the Air” report around Earth Day every year since 2000.

Higher temperatures contribute to smog pollution because smog contains ozone particles that form faster at higher temperatures, Patrick Kinney, a Boston University professor told Live Science in a 2017 report.

Wildfires that have claimed lives and destroyed property in the Western states in recent years were cited as a factor in creating ozone pollution.

“High ozone days and spikes in particle pollution, related to extreme heat and wildfires, are putting millions more people at risk and adding challenges to the work states and cities are doing across the nation to clean up air pollution,” the report states.

Minority communities are at a significantly higher risk of breathing in polluted air, the report found. Non-white people are 61 percent more likely than white people to live in a county that failed at least one category, and they are more than three times as likely to live somewhere that had a failing grade for all three.

The 13 counties that failed all three are mostly urban areas, with nearly 20.7 million people — including 14 million minority residents — living there.

The report also ranked the most polluted cities in all three categories, with places in California accounting for a majority of the 25 in all three.

Los Angeles kept its No. 1 spot for worst ozone pollution, as Bakersfield, California, had the worst year-round particle pollution and Fairbanks, Alaska, the worst short-term particle pollution.

The five “cleanest places to live” were also listed: Burlington-South Burlington-Barre, Vermont; Charlottesville, Virginia; Elmira-Corning, New York; Urban Honolulu, Hawaii; and Wilmington, North Carolina.