Wildfire smoke has become the deadliest form of air pollution in the United States, killing more than 24,000 Americans every year according to a UCLA study published in early 2026. That's more deaths than murder and more than any other type of air pollution. As the 2026 wildfire season has already burned 2.4 million acres by early June,nearly double the 10-year average for that time of year,air quality alerts have spread across more than a dozen states, and the American Lung Association warns that wildfires are now the primary driver of worsening air quality in the West.

Why Is Wildfire Smoke So Much Deadlier Than Other Air Pollution?

Wildfire smoke is not simply dirty air. It's a complex mixture of gases and fine particles, including carbon monoxide, nitrogen oxides, volatile organic compounds, and PM2.5 (fine particulate matter smaller than 2.5 microns in diameter). The danger lies in PM2.5's ability to bypass your nose and upper airway's natural filtering mechanisms and penetrate deep into the alveoli, the tiny air sacs in your lungs where oxygen exchange happens.

Once PM2.5 particles reach the deep lungs, they trigger inflammation, impair oxygen exchange, and can cross directly into the bloodstream. This is fundamentally different from larger particles that get filtered out before reaching sensitive lung tissue. The American Lung Association notes that smoke from wildfires can harm people many miles downwind, and the harms accumulate over days and weeks of elevated exposure, not just during acute peak events. In documented cases, smoke from Canadian fires has produced unhealthy PM2.5 levels in Florida, and the 2023 Quebec fires blanketed New York City and the Eastern Seaboard.

Who Is Most Vulnerable to Wildfire Smoke Exposure?

The health risk from wildfire smoke falls hardest on specific populations whose underlying biology or medical conditions make them less able to tolerate PM2.5 exposure. Understanding these groups is critical because their risk compounds in ways that go beyond simple respiratory irritation.

• People with asthma and COPD (chronic obstructive pulmonary disease): Wildfire smoke is a potent trigger for exacerbations in both conditions. The fine particles and chemical irritants cause airway inflammation, bronchospasm, increased mucus production, and decreased peak flow. People with asthma who already have inflamed, hyperreactive airways face a dramatically amplified response to smoke exposure.
• People with heart disease: The connection between PM2.5 exposure and cardiovascular outcomes is one of the most robustly documented findings in environmental health research. Fine particles that enter the bloodstream trigger systemic inflammation, endothelial dysfunction, increased blood viscosity, and elevated risk of plaque rupture, all of which translate directly into elevated risk of acute heart attack, stroke, and arrhythmia. Epidemiological studies show elevated cardiovascular events in the days following elevated smoke exposure, even in individuals who did not experience respiratory symptoms.
• Pregnant individuals and fetuses: Wildfire smoke exposure during pregnancy has been linked to adverse birth outcomes, including preterm birth, low birth weight, small for gestational age, and fetal growth restriction. Research published in Lancet Planetary Health found that wildfire smoke exposure during pregnancy was associated with significantly elevated odds of preterm birth across multiple U.S. studies. PM2.5 can cross the placenta, and the chronic oxidative stress produced by smoke exposure can disrupt placental blood flow and fetal development.
• Children and older adults: Children's lungs are still developing, and they breathe proportionally more air for their size, delivering more pollutants per pound of body weight than adults. Older adults have reduced respiratory reserve and are more likely to have underlying cardiovascular and pulmonary conditions that compound their smoke risk.

The American Lung Association recommends taking extra precautions for children and teens, whose developing lungs are particularly susceptible to long-term damage.

How to Protect Yourself and Your Family From Wildfire Smoke

• Check air quality before outdoor activity: Use AirNow.gov or the EPA's Fire and Smoke Map to check the Air Quality Index (AQI) by location before any outdoor activity, including exercise, dog walking, and children's outdoor play. When AQI exceeds 100 (unhealthy for sensitive groups), people with respiratory or cardiovascular conditions should limit outdoor activity. When AQI exceeds 150 (unhealthy for everyone), all people should reduce outdoor exposure.
• Stay indoors with windows closed on high-smoke days: Keep windows and doors closed and run air conditioning in recirculation mode (not fresh air intake) to filter indoor air without drawing in smoky outdoor air. Portable HEPA air purifiers are highly effective at removing PM2.5 from indoor air.
• Use N95 respirators, not cloth or surgical masks: Cloth masks and standard surgical masks do not filter fine particles effectively. An N95 respirator, properly fitted and covering nose and mouth without gaps, is the minimum effective protection if outdoor exposure is unavoidable. However, the American Lung Association notes that N95s may not fit properly for children and can be difficult for people with lung disease to use; consult your physician before using them in those cases.
• Maintain an asthma or COPD action plan: If you have asthma or COPD, keep your rescue inhaler accessible and maintain an emergency action plan with your physician that specifies when to use controller medications, when to use rescue medication, and when to seek emergency care.

These protective steps are not optional during high-smoke events. The American Lung Association emphasizes that anyone with a respiratory condition should treat air quality alerts as serious medical advisories and take proactive protective steps.

What Does the 2026 Wildfire Season Look Like So Far?

The 2026 wildfire season has already earned a grim distinction before summer has officially started. As of early June 2026, fires had burned 2.4 million acres in the U.S., nearly double the 10-year average for the start of June. The National Interagency Fire Center places this on pace for one of the earliest-burning seasons in modern recorded history, with months of peak fire weather still ahead.

The consequences for air quality are active and wide-reaching. Air quality alerts have been issued across more than a dozen states as wildfire smoke, driven by western fires and Canadian fires traveling south and east, has pushed fine particle pollution to levels that are unhealthy for sensitive groups and, in the most affected areas, unhealthy for everyone. The American Lung Association's finding is stark: while industrial, power plant, and transportation emissions have steadily declined over the past three decades, wildfire emissions have surged to levels that are overwhelming the gains and reversing decades of progress achieved through the Clean Air Act.

"Wildfires are now the primary driver of worsening national air quality in the West," the American Lung Association confirmed in its tracking of the intersection of wildfires and air quality.

American Lung Association

With approximately 17% of the U.S. already in extreme drought and El Niño expected to bring drier, hotter conditions, the outlook for the remainder of the 2026 season remains concerning. The states most affected include California, Oregon, Washington, Idaho, Montana, Nevada, and Arizona, plus northern states experiencing smoke from Canadian fires.