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‘State of the Air’ 2017 Report Finds Denver Air Quality Improved

(April 19, 2017) -

The American Lung Association’s 2017 “State of the Air” report found that while Denver has earned overall mixed grades for the three most common forms of hazardous air pollution, the area’s air pollution levels have improved from last year’s report.  

Denver County earned a D in ozone pollution and an F in short-term particle pollution, while Jefferson County also failed in the ozone category.* 

However, Denver’s ozone pollution levels have improved and the city bettered its ranking on the list of most-polluted cities for ozone, coming in at No. 11. For short-term particle pollution, though, there were more average unhealthy days and the city ranks 30 on the most-polluted list for the category. Previously, the Denver metro area didn’t have enough data to record year-round particle pollution, but there was sufficient information for the 2017 report, which showed that the Denver area meets air quality standards and is ranked 131.  

“The 2017 ‘State of the Air,’ report found continued improvement in air quality across the country, but 40 percent of Americans still live with unhealthful levels of either ozone or particle pollution placing their health at risk,” said Dawn Mullally, director of air quality and transportation for the American Lung Association in Colorado. “Even though Denver saw improvements from last year’s report, residents are still exposed to high levels of pollution, which can put them at risk for premature death and other serious health effects such as asthma attacks, worsened chronic obstructive pulmonary disease (COPD) symptoms and cardiovascular harm. Our high levels of year-round particle pollution also place our citizens at greater risk for lung cancer.” 

Elsewhere in Colorado, Fort Collins also had mixed grades. The area is ranked 15 on the list of most-polluted cities for ozone, an improvement from last year. Fort Collins also returned to the year-round particle pollution list with enough sufficient data, ranking at 158. Larimer County’s short-term particle pollution worsened from last year, receiving a C, and Fort Collins is ranked at 46th.  Two Colorado cities, Colorado Springs and Pueblo-Canon City, made the cleanest cities lists for short-term and year-round particles. Other cities throughout the state earned spots on the cleanest cities list. 

The most notable national findings of the 18th annual report were lower overall ozone levels and lower year-round particle levels, offset by a continued trend of extreme short-term spikes in particle pollution, often related to wildfires or droughts. The report finds that the health of 43 million people across the country are at risk from these dangerous spikes in particle pollution.  

Each year the “State of the Air” reports on the two most widespread outdoor air pollutants, ozone pollution (smog) and particle pollution (soot). The report analyzes particle pollution in two ways: through average annual particle pollution levels and short-term spikes in particle pollution. Both ozone and particle pollution are dangerous to public health and can be lethal. But the trends reported in this year’s report, which covers data collected by states, cities, counties, tribes and federal agencies in 2013-2015, are strikingly different for these pollutants, nationwide, and in Denver. 

Ozone Pollution in Denver

Compared to the 2017 report, Denver experienced fewer unhealthy days of high ozone in this year’s report. Nationwide, ozone pollution has decreased, thanks to the Clean Air Act’s success at cleaning up major sources of the emissions that create ozone, especially coal-fired power plants and vehicles. However, research shows that climate change causes warmer temperatures, which makes ozone harder to clean up. 

“Ozone is harmful to public health and especially children, older adults and those with asthma and other lung diseases,” Mullally said. “When they breathe ozone-polluted air, too often they end up in the doctor’s office, the hospital or the emergency room.”

Particle Pollution in Denver

“State of the Air” 2017 found year-round particle pollution (soot) levels in Denver County are well below the national air quality standards. Nationwide, the best progress in this year’s report came in reducing year-round levels of particle pollution.

Particle pollution is made of soot or tiny particles that come from coal-fired power plants, diesel engines, wildfires and wood-burning devices. These particles are so small that they can lodge deep in the lungs and trigger asthma attacks, heart attacks and strokes. They can even cause lung cancer, and early death.

“Across the country, year-round particle pollution levels have dropped thanks to the cleanup of coal-fired power plants and the retirement of old, dirty diesel engines,” Mullally said. “This is something we’ve benefited from in Denver, with Colorado’s clean air policies.”

Short-term spikes in particle pollution can be extremely dangerous and even lethal. According to the 2017 report, Denver County had more days when short-term particle pollution reached unhealthy levels in 2013-2015. This is keeping in line with the national trend of increased short-term spikes in particle pollution. 

Climate is known to cause increased heat, changes in weather patterns, drought and wildfires, which   contributed to the extraordinarily high numbers of days with unhealthy particle pollution in some cities, including Denver. 

“Healthy air protections are under attack, and must be defended to save lives here and across the country. Air travels from one state to another, so only federal protections can help protect the air we all breathe,” Mullally said. “The Lung Association in Colorado calls on President Trump, EPA Administrator Scott Pruitt and members of Congress to fully fund, implement and enforce the Clean Air Act for all air pollutants – including those that drive climate change and make it harder to ensure healthy air for all Americans.”

Learn more about Denver’s rankings, as well as air quality across Colorado and the nation in the 2017 “State of the Air” report at For media interested in speaking with an expert about lung health and healthy air, contact the American Lung Association in Colorado at [email protected] or 312-801-7631. 

*Jefferson County did not have sufficient date for evaluation in the short-term and annual particle pollution categories.


About the American Lung Association in Colorado 

The American Lung Association is the leading organization working to save lives by improving lung health and preventing lung disease, through research, education and advocacy. The work of the American Lung Association is focused on four strategic imperatives: to defeat lung cancer; to improve the air we breathe; to reduce the burden of lung disease on individuals and their families; and to eliminate tobacco use and tobacco-related diseases. For more information about the American Lung Association, a holder of the Better Business Bureau Wise Giving Guide Seal, or to support the work it does, call 1-800-LUNGUSA (1-800-586-4872) or visit the newly redesigned website:

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