Poor Air Quality Impacting U.S. States
Air quality has recently deteriorated across multiple U.S. states due to smoke from Canadian wildfires, regional fires, and summer ozone pollution. These factors have combined to create potentially unhealthy conditions for millions of residents.
The problem is multifaceted. Wildfire smoke from Canada has moved south into the Midwest and Northeast. Simultaneously, fires burning in the western U.S. are locally contributing to smoke. As of mid-July 2026, the National Interagency Fire Center reported 40,560 wildfires in the U.S. this year, which have burned over 3.8 million acres.
Additionally, stagnant, hot air can exacerbate ground-level ozone pollution. This occurs when sunlight and heat react with pollutants from vehicles and industries. Light winds may prevent this pollution from dispersing, causing a buildup near the ground.
Air Quality Alerts Across States
Between July 19 and July 20, National Weather Service Air Quality Alerts highlighted warnings across several states:
- Indiana
- Illinois
- Ohio
- Pennsylvania
- Colorado
- Idaho
- Washington
- West Virginia
- Michigan
- Minnesota
- Iowa
- Wisconsin
- Oregon
In Michigan, officials issued an alert due to elevated PM2.5 from wildfire smoke. Minnesota saw heavy smoke expand into the east and south-central regions, pushing the Air Quality Index to the “Red” category. Iowa reported PM2.5 reaching unhealthy levels, especially near key cities.
Wisconsin expected PM2.5 levels to reach “Unhealthy” to “Very Unhealthy” in certain areas, whereas Illinois cited unhealthy smoke and ozone levels. Indiana and Ohio faced similar concerns.
Further west, wildfire smoke also affected Oregon, Idaho, Washington, and parts of Colorado.
Growing Wildfire Influence on Air Quality
Wildfire smoke is increasingly contributing to air pollution nationwide. The EPA notes an increase in large and catastrophic fires globally, including in Canada and Mexico, leading to significant PM2.5 pollution.
Data between 2006 and 2020 shows that both the intensity and reach of wildfire smoke have grown, affecting larger areas than before. Consequently, remote communities are experiencing degraded air quality.
Risks of Wildfire Smoke
Wildfire smoke contains fine particulate matter, known as PM2.5. These particles can penetrate deep into the lungs, entering the bloodstream. The CDC recognizes that smoke can impact regions far from a fire, increasing emergency department visits, hospital admissions, and fatalities.
Vulnerable groups include children, older adults, pregnant individuals, outdoor workers, and those with respiratory or heart conditions. At “Unhealthy” AQI levels, the general population may also have symptoms like:
- Coughing or wheezing
- Shortness of breath
- Burning eyes, nose, or throat
- Chest tightness
- Fatigue or dizziness
- Palpitations or unusual heart symptoms
Long-Term Health Risks
A 2026 study in Science Advances estimated that long-term exposure to wildfire smoke contributed to 24,100 deaths annually in the lower 48 states from 2006 to 2020. Smoke PM2.5 has shown no safe exposure threshold.
Another Stanford-led study estimated 41,380 annual excess deaths due to smoke exposure between 2011 and 2020. Projections suggest a 70% increase by 2050 could result in economic damage worth $608 billion per year.
Harvard researchers found health effects lasting up to three months after exposure. The study linked smoke to higher hospitalization risks for several conditions including:
- Coronary heart disease
- Cerebrovascular disease
- Arrhythmia
- Hypertension
- Pneumonia
- Chronic Obstructive Pulmonary Disease (COPD)
- Asthma
Exercise and Exposure
Heavy breathing during activities increases particle inhalation. Research shows exercise leads to inhaling eight times more air than at rest. This affects exposure during activities like:
- Walking the dog
- Jogging
- Hiking
- Cycling
- Gardening
- Playing outdoor sports
EPA-cited studies connect smoke episodes to spikes in asthma-related emergency visits. CDC guidance states smoke can exacerbate chronic conditions like asthma and heart failure.
Research shows links between smoke exposure and heightened cardiovascular risk. NIH studies found associations between PM2.5 and lung cancer mutations in non-smokers.
Recommendations for Staying Safe
Public health officials suggest checking AirNow.gov or regional forecasts for air quality. When smoke or ozone is high, consider:
- Staying indoors with windows and doors shut
- Using air conditioning with a high-efficiency filter
- Avoiding strenuous outdoor activities
- Exercising indoors
- Wearing an N95 mask outside in smoky conditions
- Keeping asthma medication on hand
- Seeking medical help for severe symptoms