How Air Purifiers Help During Wildfire Season

Written By Meg Christensen

Wildfire season brings not only the danger of flames but also lingering smoke that can travel hundreds of miles, affecting air quality far from the fire's origin. As these events become more frequent and intense due to climate change, protecting your indoor air is more important than ever. In this blog, I’ll explain the health risks of wildfire smoke, how it affects indoor environments, and why a high-quality air purifier for smoke can make a significant difference. With guidance from trusted sources like the EPA, CDC, and American Lung Association, we’ll explore both the science and the practical steps to take during wildfire season.

Drifting wildfire smoke from a burning forest seen from above.

Why Wildfire Smoke Is Harmful

Wildfire smoke contains a mix of gases and fine particulate matter (PM2.5), which are tiny particles with a diameter of 2.5 microns or smaller. These particles are roughly 30 times smaller than a human hair and can penetrate deep into the lungs, entering the bloodstream. The EPA identifies PM2.5 as the primary health threat from wildfire smoke.

Short-term exposure to wildfire smoke can cause coughing, wheezing, sore throat, and eye irritation. For people with asthma or other chronic lung conditions, it can trigger severe symptoms and flare-ups. Long-term or repeated exposure has been linked to increased risks for heart attacks, reduced lung function, and premature death. Children, older adults, pregnant women, and people with chronic illnesses are especially vulnerable. Even healthy individuals may experience fatigue, chest discomfort, or respiratory inflammation during prolonged smoke exposure.

According to the CDC, the effects of wildfire smoke are not limited to physical symptoms. People exposed to heavy smoke for days or weeks may also experience increased stress, poor sleep, and worsening of mental health conditions due to indoor confinement or reduced physical activity.

It's Not Just Trees Burning Anymore

Today’s wildfires often burn through more than just forestland. Homes, cars, paints, plastics, treated lumber, pesticides, and other chemical-laden materials are frequently caught in the flames. This creates a far more toxic smoke mixture than a typical wood fire. These burning materials release dangerous compounds, like heavy metals, phthalates, and polycyclic aromatic hydrocarbons (PAHs), that are harmful to breathe, even in small doses. The result is a type of smoke that is more hazardous to human health than many people realize.

Orange haze from wildfire smoke in a downtown area with skyscrapers.

How Smoke Enters Your Home

Even if you're far from the flames, smoke can infiltrate your home through windows, doors, and ventilation systems. Most homes are not airtight, and during wildfire events, tiny smoke particles can find their way inside through the smallest gaps. Once indoors, these particles accumulate and linger, especially if your home lacks adequate filtration.

Research from the EPA shows that during wildfire events, indoor levels of PM2.5 can reach 70% of outdoor levels if no air purification measures are taken. That means even staying inside doesn’t guarantee clean air unless additional precautions are in place. Simply closing windows isn’t enough: you need an active way to remove smoke particles from the air.

How Air Purifiers Help

Air purifiers, especially those with high-efficiency particulate air (HEPA) filters, are one of the most effective tools for removing wildfire smoke particles from indoor air. A true HEPA filter can trap 99.97% of airborne particles as small as 0.3 microns, which includes the majority of smoke particles.

Many modern air purifiers also include activated carbon filters, which help absorb odors and volatile organic compounds (VOCs) found in wildfire smoke. This combination of filters allows a good air purifier for smoke to target both the solid particles and the gaseous pollutants present in smoky air.

When choosing an air purifier for smoke, look for:

  • True HEPA filtration – Avoid "HEPA-type" filters, which may not meet the same efficiency standards.

  • Smoke-specific Clean Air Delivery Rate (CADR) – Higher CADR ratings mean faster air cleaning.

  • Activated carbon filter – Helps neutralize odors and chemicals.

  • Proper room size coverage – Ensure the unit is powerful enough for the space where it will be used.

Avoid ozone-generating models, which can irritate the lungs and are not recommended by health authorities. Ozone is itself a respiratory irritant and can worsen the very symptoms you’re trying to avoid.

Creating a Clean Air Room

One effective strategy during wildfire season is to set up a "clean air room" in your home. This is a designated space where you can maintain the best possible air quality. Ideally, this would be a bedroom or another area where you spend a lot of time. Here’s how to create one:

  1. Seal the room: Close windows and doors, and use weather stripping or towels to block gaps.

  2. Run a HEPA air purifier continuously: Choose a unit that can handle the size of the room and run it on high when smoke is heavy.

  3. Avoid activities that generate indoor pollution: Don’t burn candles, smoke, fry food, or vacuum without a HEPA-filtered vacuum.

  4. Use a portable fan if needed: For comfort, as long as it doesn’t draw air from outdoors.

This clean room can provide a refuge, especially for children, seniors, and those with respiratory conditions.

Additional Tips for Cleaner Indoor Air

Alongside using an air purifier, the following practices can help keep your indoor air safer during wildfire season:

Air purifier in a calm household space with a plant.

  • Use HVAC systems wisely: If your system allows, install a high-efficiency filter (MERV 13 or higher). Set your system to "recirculate" so it doesn’t draw in outside air.

  • Avoid adding to indoor pollution: Skip the candles, incense, wood-burning stoves, and aerosol sprays.

  • Monitor air quality: Use reliable sources like AirNow.gov to track the Air Quality Index (AQI) in your area and know when it’s time to act.

  • Keep spare filters on hand: During extended smoke events, filters can clog quickly. Replacing them on schedule ensures continued effectiveness.

  • Consider DIY options in emergencies: A box fan with a MERV 13 furnace filter taped to the back can offer temporary relief if commercial air purifiers are unavailable. However, use with caution and never leave it running unattended.

Choosing the Right Air Purifier

Not all air purifiers are created equal. Here are key considerations to guide your purchase:

  • CADR Ratings: The Clean Air Delivery Rate (CADR) measures how quickly the purifier can clean air in a specific size room. Look for a smoke CADR that matches your room’s square footage.

  • Filter Replacement Costs: HEPA and carbon filters need to be changed regularly. Check replacement frequency and cost before buying.

  • Noise Levels: If the purifier will run in a bedroom or office, check user reviews or decibel ratings to ensure it won’t disturb sleep or work.

  • Ozone-Free Certification: Look for purifiers certified by California’s Air Resources Board (CARB) to ensure they produce little or no ozone.

  • HEPA and Gas Filtration: Ensure the unit includes both a True HEPA filter and an activated carbon or mineral blend filter. This dual capability allows the purifier to capture both particulate matter and gases, which are the two major health risks from wildfire smoke.

For more detailed guidance on choosing the best purifier for you, visit my air purifier guide.

Final Thoughts

As wildfire smoke becomes a seasonal reality, protecting your indoor air quality is one of the most important things you can do for your health. A well-chosen air purifier for smoke can significantly reduce exposure to harmful particles, making your home a safer space during smoke events.

Clean air supports better respiratory, cardiovascular, and overall health, especially for vulnerable individuals. By taking proactive steps to create a clean air space, monitor outdoor air quality, and avoid indoor pollutants, you can breathe easier no matter what wildfire season brings.

Sources:

Meg Christensen https://www.interiormedicine.com