Wildfires, Shut-Downs, and Behavior Change: 2020 Has Been a Big Year for Air Quality and Health

Many Coloradans have been waking up to what has become a familiar sight and smell during 2020: wildfire smoke.

Months of hazy skies may seem especially jarring to Coloradans after their experience with clearer air this spring during Colorado’s stay-at-home-order, issued in response to the COVID-19 pandemic. The widespread behavior changes spurred by the month-long order resulted in lower levels of pollutants such as nitrogen dioxide and sulfur dioxide, as CHI explored in a recent report, Catalyst or Challenge.

The report also highlights a positive longer-term trend occurring in the Denver metro area: Air quality for some pollutants has been improving in the past 10 years due to more focused regulations and policies to promote healthy air.

However, the 2020 wildfire season has made the cleaner air of spring seem like a distant memory as much of Colorado has been blanketed with harmful smoke, which can negatively impact health, especially for sensitive groups.

Two of the three largest fires in Colorado’s history have occurred in 2020, causing local evacuations and, in the case of the Cameron Peak Fire, a massive smoke plume that filled the air with unhealthy pollutants. And Colorado’s fires are not the only contributors to smoky skies across the state. One of the worst wildfire seasons on record in California, Oregon, and Washington has sent smoke across the country and into Colorado’s air.

Wildfire Smoke Negatively Impacts Human Health

Wildfires in Colorado have grown larger and more intense in the past 30 years, and that trend is projected to continue, according to state climate scientists.  A combination of forest management and fire suppression practices along with warmer temperatures, drier conditions, and the infestation of bark beetles has primed Colorado’s forests for the destructive fires we see today.

An uptick in large fires in Colorado and the western United States is a growing concern for communities living in or near wildland urban interfaces (WUI), but also for those who live hundreds of miles away. A wildfire’s damage extends far beyond its flames, as smoke can travel across state lines, and even across the country. The smoke contains toxic gases, such as carbon monoxide and minuscule particles called particulate matter 2.5.

Health impacts from exposure to wildfire smoke vary based on several factors, such as a person’s preexisting health conditions, length of exposure, weather patterns, and the level of pollutants as measured by the Air Quality Index (AQI).

Figure 1. The impact of climate change on wildfire behavior and human health.

Some Populations Are More at Risk

An NPR analysis of U.S. Environmental Protection Agency data showed that one in seven Americans experienced at least one day of unhealthy air this summer.

But the risk of adverse health effects is not shared equally among exposed residents. CHI’s 2019 Health and Climate Index and 2017 report, Colorado’s Climate and Colorado’s Health, outline several sensitive groups that are vulnerable due to heightened smoke levels. CHI found that Coloradans who work outside, live in low-income communities, have preexisting health conditions, or are pregnant are among those who face increased health risks from wildfire smoke. 

And Coloradans have another health risk to worry about in 2020: COVID-19. The presence of a global pandemic throws another wrench into the challenges faced by sensitive populations. Scientists note that a weakened immune response from extended exposure to wildfire smoke can exacerbate the impact of the virus.

Individual, Local, and State Policies Can Reduce Risks

Health officials and policymakers have many health risks to juggle in 2020. The projected trend of more intense and large wildfires, in addition to the unknown trajectory of the coronavirus pandemic, is daunting. However, steps can be taken to protect the air we breathe.

Wildfires are a natural phenomenon in Colorado and the West, but proper fire mitigation practices and awareness of health effects can reduce the damage done to both our forests and our lungs.

The Colorado State Forest Service (CSFS) has been working to improve public awareness about wildfire mitigation practices for residents who live in WUIs. CSFS partnered with the National Fire Protection Association to certify 150 Colorado communities as FireWise, meaning they have taken steps to reduce wildfire risks to their homes and businesses.

State legislators have also taken action to improve wildfire mitigation practices with the passage of House Bill 19-1006. The bill committed the state to funding forest restoration projects and grant programs that aim to reduce wildfire risk to the 2.9 million Coloradans who live in WUIs.

Hospitals and community clinics that treat higher rates of sensitive populations can communicate the health risks related to wildfire smoke and also take the necessary measures to prepare for increased visits during high smoke days. 

At an individual level, the Centers for Disease Control and Prevention recommends that people stay up-to-date and pay attention to air quality conditions in their area.  Awareness of current air quality levels can allow residents, especially those who are sensitive populations, to plan accordingly by avoiding unnecessary trips outdoors. Coloradans can sign up for air quality alerts or check the current AQI at Airnow.gov.


In 2020, many Americans have been confronted by the importance of air quality to health and overall quality of life. The clean air and clear skies enjoyed by many Coloradans were a silver lining of the COVID-19 pandemic this spring. Now, millions of people are seeing and feeling the far-reaching effects of wildfire smoke. That hard-won awareness creates an opportunity for Colorado’s policymakers, businesses, and residents to take steps to support healthy air quality – now and in the future.

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