The health consequences of wildfires in Canada were felt across the United States for the past few summers. On July 31, 2025, Chicago air quality ranked among the worst in the world.
Poor air quality from wildfire smoke and other pollutants is harmful to everyone, even those with no known preexisting conditions. Air quality can change from day to day, so knowing how to protect yourself is crucial.
Smoke from distant wildfires can impact air quality in Illinois, and symptoms can show within just days of wildfire smoke exposure. Prolonged exposure can damage the lungs and heart, or even weaken your immune system.
The following are some of the symptoms and health risks that may result from wildfire smoke and pollutants, as well as prevention best practices.
General symptoms
- Eye irritation
- Fatigue
- Sneezing
- Coughing and/or wheezing
- Shortness of breath
Respiratory effects
- Inflammation
- Bronchitis
- Impaired lung function
- Worsening asthma
- Higher lung cancer risk
Cardiovascular effects
- Heart failure
- Heart attack
- Stroke
- Atrial fibrillation
Wildfire smoke is especially dangerous because of the fine particles it produces. With a diameter 30 times smaller than a piece of hair, these particles easily enter the nose and throat before traveling to the lungs and bloodstream. Compared to pollution particles the same size, wildfire smoke is up to 10 times more harmful.
Other harmful air pollutants
In addition to wildfire smoke, other harmful pollutants also lower air quality. These exist both indoors and outdoors, with the most common sources being:
Indoor
- Fuel-burning appliances
- Building materials and furnishings
- Household cleaning products
- Excess moisture
Outdoor
- Electric utilities
- Burning fuel
- Transportation vehicles/equipment
- Manufacturing processes
While our bodies have defense systems against some pollutants, too much exposure can overwhelm these defenses and render them less effective. Plus, tiny particles from wildfire smoke quickly bypass our natural defenses, like nose hair.
Risk factors
The exposure to daily pollutants and wildfires is a global health concern. Certain risk factors increase the likelihood of negative health effects:
- Asthma
- Lung cancer
- Chronic obstructive pulmonary disease (COPD)
- Heart disease
- Allergies
- Age (children and adults older than 65)
- Pregnancy
- Compromised immune system
Prevention
Prevention and early intervention are key to combating poor air quality. Here’s how you can stay safe:
- Keep up with air quality forecasts. Consider downloading an app or using AirNow. The New York State Department of Public Health provides a simple guide to understanding the air quality index.
- Wear a mask. Using an N-95 mask is recommended in addition to double-masking.
- Evacuate or shelter inside if you can. If you are unable to relocate, try to find shelter indoors.
- Close windows and doors. This prevents harmful particles from entering your home or vehicle.
- Run AC on recirculate with a new filter. You will avoid inhaling vehicle exhaust.
- Use a CARB-certified air cleaner. These are portable and will help protect your home.
- Avoid vacuuming, frying food, or using gas-powered appliances. This reduces the number of unnecessary particles in the air.
- Make an appointment with your healthcare provider. Even if symptoms seem mild, seek care immediately if you have any concerns.
Make sure to routinely monitor air quality and limit exposure when air quality conditions decline to protect your health.
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