In summer 2023, wildfire smoke from Canada turned the sky over New York City an eerie orange, trapped Chicago under a blanket of haze, and drove air quality into dangerous territory up and down the eastern seaboard. Millions of people who’d never been near a wildfire before were suddenly inhaling harmful wildfire smoke.
Wildfires are a fact of life in America these days, likely fueled by warmer temps and worsening drought. And they’re fast becoming everyone’s problem.
Not only do they destroy homes and even entire neighborhoods where they happen, they send toxic smoke, gases, and fine particulate matter far and wide. The air you’re breathing where you live could be the polluted by-product of an out-of-control fire burning clear across the country.
The threat is real, and it’s getting worse:
- Extreme wildfire activity has more than doubled worldwide1
- Wildfire smoke can travel hundreds, even thousands, of miles2
- US deaths from wildfire smoke could top 70,000 annually by 20503
In this guide, you’ll learn what makes wildfire smoke so dangerous, as well as how to protect yourself from serious wildfire smoke health effects.
Wildfire smoke forecast
Wildfires, unplanned fires in wildlands such as forests and grasslands, are common in the western US. Wildfire season typically runs from May to November, with most wildfires happening during the summer months.
“In the early 1950s, the season lasted about five months, but due to climate change and worsening conditions, it now stretches to around seven months,” according to the Western Fire Chiefs Association.5
And the numbers are trending upwards. In the 1980s, for example, the US averaged just two major wildfires a year. Between 2014 and 2023, that number jumped to nine annually.6
Wildfire smoke map
More than one-third of the US population lives in counties with high wildfire risk.7 But the risk doesn’t stop at the fire line.
Bigger fires cause massive smoke plumes that travel more and more miles, expanding the reach of any single fire dramatically. Today, wildfire smoke impacts air quality across the US due to smoke dispersion.8
Bottom line: You don’t have to be anywhere near a wildfire to be harmed by it. And when the whole country is at risk from wildfire smoke, protecting your health no matter where you live becomes critical.
What makes wildfire smoke so dangerous?
Wildfire smoke isn’t just a single substance. It’s a complex mixture of health hazards that includes:
- Particulate matter (PM2.5): perhaps the greatest health concern, these microscopic particles are small enough to evade the body’s natural defenses and enter the bloodstream9
- Carbon monoxide (CO):a colorless, odorless gas that enters the bloodstream through the lungs and reduces oxygen delivery to organs and tissues10
- Volatile organic compounds (VOCs): gas-phase chemical compounds, many of which are toxic and some carcinogenic (benzene, formaldehyde, etc.)11
- Ground-level ozone: a toxic respiratory irritant formed when primary pollutants like the ones above enter the atmosphere12
- Nitrogen oxides:additional wildfire combustion by-products that are harmful to human health13
- Toxic residue/heavy metals: lead, arsenic, mercury, etc. released from burning soil, buildings, and more14
You may not know: Smoke oxidizes as it travels, changing from primary to secondary pollutants. That means smoke that reaches places far from the wildfire source may contain different, and sometimes more harmful, chemical compounds than smoke near the wildfire itself.15
The urban wildfire problem
Not all wildfire smoke is the same. Wildfires in the wildland-urban interface (WUI)—where cars, homes, synthetic materials, and other human-made structures burn alongside vegetation—produce smoke with complex, toxic chemicals.16
Research following the January 2025 Los Angeles wildfires found significantly higher levels of some VOCs in the post-fire period. This was particularly evident in vacant homes inside the burn zones, suggesting persistent emissions from smoke-impacted materials.17
“These findings underscore the need for targeted interventions to minimize indoor exposures during the recovery phase,” said study co-author Dr. Michael Jerrett, professor in UCLA Fielding’s Department of Environmental Health Sciences and the Jonathan Fielding Chair in Climate Change and Public Health. “These findings raise concerns about indoor air quality post-wildfire, and the potential for prolonged exposure leading to significant health impacts.”
Health effects of wildfire smoke
You can run, but you can’t hide from wildfire smoke. Even closing the windows doesn’t fully protect you, as smoke has a way of getting in despite your best efforts.
And as Helen Christoni, Air Quality Expert & SVP, AirDoctor, says, “There’s no such thing as safe wildfire smoke. Toxic substances and particulate matter from wildfires are sticky — they can adhere to surfaces for up to several years, even hundreds of miles from where that fire started.”
The danger to your health cannot be overstated. Our lungs simply aren’t designed to filter smoke-filled air, and our bodies suffer the consequences.
In the short-term
During or shortly after smoke exposure:
- Eye, nose, and throat irritation18
- Coughing, wheezing, difficulty breathing18
- Chest pain, shortness of breath18
- Asthma, respiratory inflammation19
- Emergency room visits, hospitalizations20
- Decreased cognitive performance, effects on mental health and well-being21
Over the long-term
With repeated or prolonged smoke exposure:
- Increased susceptibility to flu infection22
- Neurological damage to the brain23
- Higher mortality from cardiovascular disease24
- Increased risk of respiratory disease and reduced lung function25
- Increased risk of pre-term birth and low birth weight22
- Increased risk of cancer and premature death22
Importantly, the EPA notes that there is no PM2.5 concentration below which health effects have not been observed.26 In other words, there’s no safe level of wildfire smoke exposure, which makes protecting your indoor air quality a necessity.
When wildfires are burning, outdoor air quality often gets most of the headlines. But your indoor air can be just as concerning, sometimes more so. Wildfire smoke infiltrates homes through tiny gaps and cracks as well as HVAC systems. And unless you have active air filtration, the air inside your home can quickly become unhealthy. Here are some tips for keeping your indoor air safe, both during and after a wildfire: Not all air purifiers are created equal—most only do half the job of purifying your air. You need an air purifier that truly protects you from all of the contaminants in wildfire smoke, which includes ultra-fine PM2.5 particles plus toxic gases and VOCs. Designed to trap 99.97% of particles as small as .3 microns, HEPA filters are effective at capturing those dangerous ultra-fine PM2.5 particles that invade your body and wreak havoc on your health. HEPA filters can significantly improve your indoor air quality when wildfires strike. So at the very least, you want to make sure your air purifier has a HEPA filter. That said, HEPA is a 1943 standard. For the best defense, you should look for a next-level air purifier. AirDoctor features an UltraHEPAⓇ filter. It’s tested to remove particles 100x smaller than the HEPA standard. As mentioned earlier, HEPA is only half of it. What you really need is an air purifier with a HEPA filter and a carbon filter. Why? HEPA filters aren’t effective against the toxic gases (ozone, nitrogen dioxide, etc.) or VOCs (benzene, formaldehyde, etc.) from building materials, flooring, furniture, and more. Those pass right through HEPA filters. An air purifier that combines an advanced HEPA filter with an activated carbon filter addresses both threats: the HEPA filter traps particles, while the carbon filter removes gases and VOCs. AirDoctor's UltraHEPA filter captures more of the harmful particles floating in your air during wildfires. And the premium activated carbon filter enhanced with potassium permanganate goes beyond particles to remove toxic gases and convert them into stable, non-hazardous by-products. In fact, 97% of customers surveyed said they feel more confident knowing AirDoctor filters smoke from their indoor air, including wildfire smoke. Comments like these are common: “We bought our Air Doctor when we were experiencing heavy smoke from a nearby wildfire. It took care of the smoke in the house! So thankful for our Air Doctor!” “I bought 2 when Arizona wildfires relatively close to home upped my sinus symptoms to uncomfortable and my home air began smelling like soot. Within 24 hours my sinuses began resolving and soot smell was gone.” Don’t wait for the next smoke alert, be ready before wildfire smoke arrives. Get the right air purifier and stock up on extra filters—you’ll be breathing easy until everything gets back to normal. How to protect yourself from wildfire smoke
During a wildfire
After a wildfire
How to choose an air purifier for wildfire smoke removal
How do HEPA filters help with wildfire particulate matter?
Best air purifier for wildfire smoke
The AirDoctor difference
Andrea, Verified customer
Jeri, Verified customer
Key takeaways
