Air Quality


The quality and safety of the air which humans breathe (1).

Clean air is vital to good health. Air quality affects our health in a variety of ways, and poor air quality can cause irritation of the eyes, nose and throat; lead to coughing and shortness of breath; and can increase the risk for and severity of conditions such as asthma, heart attacks and strokes (2).

Nationally, federal air quality standards have contributed greatly to overall improvements. The adoption of the federal 1970 Clean Air Act (CAA) — and its 1990 update — established health-based air quality standards and regulated emission sources based on available science (3). Since their adoption, these laws have resulted in substantially decreased levels of the six monitored pollutants: carbon monoxide, sulfur dioxide, nitrogen dioxide, ozone, PM 2.5/PM 10 and lead (4). 

Illustration of how ozone forms in the atmosphere

Source: Yale Scientific (2018)

In Colorado, ozone is of particular concern. It is found in elevated levels in the Front Range region, especially during summer months, when pollution levels sometimes spike to more than 70 parts per billion (ppb), which is the Environmental Protection Agency (EPA)’s current national ambient air quality standard. Ozone is produced when sunlight causes chemical reactions between volatile organic compounds (VOCs) and nitrogen oxides (NOx) that exist in the air from sources like oil and gas activities and car tailpipes (5). In the summer months, ground-level ozone or “smog” worsens due to the presence of more sunlight and heat which in turn creates more ozone (see above figure) (6). Ozone pollution has been shown to have negative effects on human health, such as damage to the lungs. Research also shows that ozone impacts the environment, such as by causing crop damage (5). Numerous state and regional initiatives are being implemented to reduce high levels of ozone and other pollutants within the Denver Metro Area, and Jefferson County is home to several ozone monitoring stations.

Note: EPA new standard is 70 ppb as of 2015

An indoor air quality concern in Colorado and Jefferson County is the presence of radon, a naturally-occurring, radioactive gas that originates from the breakdown of uranium in the soil (7). Radon is an invisible, odorless and tasteless gas that hasn’t been connected to any short-term symptoms of illness. However, long-term exposure to radon can cause cancer. Radon is the second leading cause of lung cancer — and the leading cause among nonsmokers — in the United States, contributing to 21,000 deaths per year (8).

Radon gas enters the home when uranium-bearing granite deposits in the soil break down, causing the gas to enter the atmosphere. The most common ways for it to get into a home are through spaces between walls, cracks in the foundation, crawl spaces and other openings around the foundation of the house, such as drains and plumbing fixtures. Radon can also be found in some sources of well water. About half of the homes in Colorado have radon levels higher than the EPA’s recommended level of 4 picoCuries per liter (pCi/L), according to the Colorado Department of Public Health and Environment (7). The EPA developed a “Citizen’s Guide to Radon: The Guide to Protecting Yourself and Your Family from Radon”, which provides helpful tips, resources available to individuals and families for testing their homes for radon and facts about health risks from possible exposure.

Health Disparities and Inequities

While significant improvements have been made over the past few decades, certain populations remain especially vulnerable to effects of air pollution, such as children, older adults and individuals with a prior respiratory illness or heart disease. The health effects pollution can have on these populations is dependent on how much exposure a person has to air pollution. The effects are determined by both the concentrations of pollutants in the air and by how much a person inhales. Runners and individuals engaging in physical activity have the greatest risk of exposure (2).

Households with low income and communities of color are disproportionately affected by both indoor and outdoor air pollution, due to environmental factors such as poor housing conditions and neighborhood proximity to major transportation corridors and industrial sites (9,10,11,12). 

In Jefferson County, elevated rates of asthma are encountered among people who live along the Interstate 70 and U.S. Highway 6 corridor (see figure to the right). A 2012 study from the National Institute of Environmental Health Sciences revealed that race and ethnicity is one of the most significant predictors of whether an individual will live near contaminated air (12). Compared to white children, the prevalence of asthma is higher among children who are Puerto Rican (2.4 times), black (1.6 times) and American Indian/Alaska Native (1.3 times). 

Asthma-related hospitalization rates/100,000 persons (2013-2017)

Source: CDPHE Small Area Estimates (2014-2017

Implications and Data for Jefferson County

Community Health Needs Assessment Focus Group Findings

Focus group participants throughout Jefferson County expressed concerns about air pollution and the effects it has on the health of their families, with one person noting that “so many people have so many lung diseases.” Participants cited concerns about the effects of the former Rocky Flats Nuclear Weapons Plant as well as the visible air pollution in the area. One person stated that “I’ve lived here my whole life, and there is definitely a cloud over Denver.” Some participants expressed interest in receiving notifications on days with bad air or water quality.

The majority of participants expressed concern with the relationship between poor air quality and asthma. Many participants indicated they had children with asthma and knew of others in the community who did as well.

The focus group held in Arvada had specific concerns about the allowance of outdoor burning in an area that already has poor air quality and how this contributes to poor air quality in their neighborhood. One participant mentioned that “people [are] going to the ER and kids have asthma” due to these fires.

In addition to concerns about poor outdoor air quality, some participants expressed concerns about poor indoor air quality. These concerns were tied to radon, mold and asbestos, and residents indicated a desire for some type of testing program. Some noted that poor indoor air quality in their homes exacerbates their children’s asthma. Some were concerned with environmental tobacco or marijuana smoke and the effect it could have on children’s asthma.

Community Health Needs Assessment Key Informant Interview Findings

Many key informants expressed concerns with poor air quality in Jefferson County and the Metro Denver area, as well as the increased incidences of asthma in both adults and children.

Several key informants were concerned about asthma affecting certain populations more than others, especially those that are Hispanic or Latino or low-income.

Air quality monitoring stations in Jefferson County and the surrounding areas (2018)

CDPHE. 2018 Air Quality Data Report

Number of days ozone levels in Jefferson County were above EPA standard (2001-2016).

Ozone can be extremely variable depending on weather conditions and topography, as shown by the graph on the left. The chart on the right shows the variability within the monitoring stations across Jefferson County.

51.0% of Radon Tests in Jefferson County were over the action limit of 4.0 pCi/L, and the average test value was 4.1 pCi/L

- Colorado Environmental Public Health Tracking, CDPHE (Radon Measurements from 2005-2018)

Click here to see CDPHE's radon data tracking tool, including data at the census tract level:


Reference List

1. New South Wales Department of Health. (2010, December). Public Health Classifications Project: Determinants of Health. Retrieved from:

2. Colorado Department of Public Health and Environment. (2018). Air Quality and Your Health. Retrieved from:

3. U.S. Environmental Protection Agency. (2018). Clean Air Act Overview. Retrieved from:

4. U.S. Environmental Protection Agency. (2018). Criteria Air Pollutants. Retrieved from:

5. Cooperative Institute for Research in Environmental Sciences. (2016, August 8). Accounting for Ozone. Retrieved from:

6. U.S. Environmental Protection Agency. (2018). Basic Information about Ozone. Retrieved from:

7. Colorado Department of Public Health and the Environment (2018). Understanding Radon. Retrieved from:

8. U.S. Environmental Protection Agency (2018). Health Risk of Radon. Retrieved from:

9. Pacheco, C., Ciaccio, C., Nazir, N., Daley, C., DiDonna, A., Choi, W., … Rosenwasser, L. J. (2014). Homes of low-income minority families with asthmatic children have increased condition issues. Allergy and Asthma Proceedings, 35(6), 467–474.

10. Salam, M., Li, Y., Langholz, B., Gilliland, F., & Children’s Health Study. (2004). Early-life environmental risk factors for asthma: findings from the Children’s Health Study. Environmental Health Perspectives, 112(6), 760–765. Retrieved from:

11. National Academy of Public Administration. (2003, July). Addressing Community Concerns: How Environmental Justice Relates to Land Use Planning and Zoning (Academy Project Number 1969). Retrieved from:

12. National Institute of Environmental Health Sciences. (2012, August 10). Environmental Inequality in Exposures to Airborne Particulate Matter Components in the United States. Retrieved from:


Data Sources

Colorado Hospital Association via CDPHE: Colorado Department of Public Health and Environment:

CDPHE: Colorado Department of Public Health and Environment: Annual Air Quality Data Reports:

CDPHE: Colorado Department of Public Health and Environment:

CDPHE: Colorado Department of Public Health and Environment:

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Published on July 17, 2018

Updated on March 10, 2020