Health Effects of Wildfire Smoke

Medically Reviewed by Neha Pathak, MD on June 08, 2023
9 min read

When a wildfire rages, the flames aren't the only threat. The smoke poses its own risks. Fine particles and harmful chemicals can get into your lungs and bring on a number of health problems. Some people are more sensitive to the smoke than others, but everyone should do what they can to avoid it.

Wildfire smoke exposure can affect you whether you're near a blaze, or if the winds spread smoke hundreds of miles away.

Find out who’s most at risk for smoke-related health issues, what symptoms could be harmful, and what steps you can take to limit the amount of smoke you breathe in.

When a wildfire begins, it burns anything in its path, like trees and houses. As a result, the air around it can include gases, water vapor, and small particles. Dangerous compounds in wildfire smoke can include:

  • Carbon monoxide
  • Carbon dioxide
  • Nitrogen oxide
  • Volatile organic compounds
  • Other toxic chemicals

The smoke mixes with substances that are already in the air. Some evidence says it can raise the ozone levels in areas that have high traffic. Ozone is an air pollutant that can cause respiratory illness.

Some evidence shows that the chemical makeup of smoke can change and become more toxic as it stays in the air. Experts think this may also lead to impacts on your health. This may pose even greater dangers for your health.

What's in the smoke can affect the quality of your air -- and your health. Fine particles from the smoke can also negatively affect the quality of your outdoor and indoor air.

Certain pollutants can impact human health. These include ozone, nitrogen dioxide, and sulfur dioxide. Wildfires create massive amounts of particle pollution or particulate matter (PM). PM refers to the size of the particles. PM2.5 and PM10 are two types of PM that wildfires can create that are small enough for you to inhale. They can get into your eyes, too. PM2.5 means the particles are 2.5 microns or smaller; PM10 means they're smaller than 10 microns. Wildfire smoke is especially dangerous because it can create ultrafine particles smaller than 0.1 micron which can go deep into your lungs and into your bloodstream. As a comparison, a human hair is 70 microns across. These are some of the biggest risks from wildfire smoke. 

In addition to the size of the particles, the chemicals in the smoke can be harmful to your health, too.

That's why you should stay informed about the Air Quality Index (AQI) during wildfires. The higher the pollutant levels in the air, the higher the number on the index goes. It runs from 0 to 500 and is color-coded to indicate when the air is more or less harmful to humans. Readings over 100 are unhealthy. Anything over 301 means that the air is hazardous and anyone may be affected. 

Staying on top of the AQI is important during a wildfire because it can tell you how dangerous the air may be. 

You will still need to keep your indoor air quality as healthy as possible, too. Smoke can enter through any cracks in your home, through your air ventilation system or HVAC system, and through open doors and windows. 

Wildfire smoke can cause health issues for anyone. Exposure to fine particles may impact how well your lungs work. It can lead to inflammation. It may also impact how your body removes viruses and bacteria from your lungs.

Some common symptoms of wildfire smoke exposure include:

  • Runny nose
  • Phlegm
  • Stinging eyes
  • Cough
  • Wheezing
  • Trouble breathing
  • Scratchy throat
  • Sinus irritation
  • Chest pain
  • Headaches
  • Tiredness
  • Fast heartbeat
  • Asthma attack

In healthy people, symptoms usually go away when the smoke does.

Smoke exposure is linked to respiratory effects, including:

  • Bronchitis
  • Reduced lung function
  • Higher risk for asthma exacerbation 
  • Higher risk for other lung diseases to be aggravated
  • Increased risk of emergency room visits and hospital admissions

The smoke is linked to cardiovascular effects such as:

  • Heart failure
  • Heart attack
  • Stroke
  • Increased risk of emergency room visits and hospital admissions

It can also raise your risk for premature death.

Researchers don't know as much about the long-term effects of wildfire smoke exposure on our health. They've studied a little bit about how it affects people who are exposed for short-term periods over time -- mainly by affecting their lung function. 

Wildfires can make existing health conditions worse. This is the case if you have asthma, COPD and bronchitis, chronic heart disease, or diabetes. The risk of cardiovascular and respiratory effects goes up as the smoke gets more intense, some evidence shows.

If you have heart disease,the smoke could make your symptoms worse. You might have:

  • Chest pain
  • Racing or pounding heart (palpitations)
  • Shortness of breath
  • Tiredness

If you have lung disease, your symptoms could also get worse. You might have:

  • More trouble breathing deeply or easily
  • Cough
  • Phlegm
  • Chest discomfort
  • Wheezing
  • Shortness of breath

Your chances for health problems go up if you’re:

  • Younger than 18 years old
  • 65 or older
  • Pregnant
  • Living with a long-term condition like heart or lung disease, asthma, or diabetes
  • A wildfire fighter or an outdoor worker
  • Lacking access to affordable health care or experiencing homelessness
  • Living with a weakened immune system due to a health condition or medications

Also, if you haven’t gotten vaccinated against COVID-19, be aware that wildfire smoke can make you more likely to get lung infections, including the virus that causes COVID. If you catch the coronavirus, inhaling wildfire smoke might make your symptoms worse. Researchers aren't sure how wildfire smoke may impact those already affected by COVID, since it can affect your respiratory system in the long term.

The Interagency Wildland Fire Air Quality Response Program (IWFAQRP) was founded by the USDA Forest Service to determine the risks posed by wildfire smoke and pass that information along to both the public and to firefighters. The program has joined with the Environmental Protection Agency (EPA) to create this fire and smoke map

You can use the map to see what fires may be in your region and check the most recent air quality measurements in your area.

Take safety measures like these:

Track the fire. Use thefire and smoke map to stay up to date on conditions in your area. 

Check your air quality. Know the AQI in your area. Follow the instructions on going outside and exercising for “sensitive individuals.” Pay attention to any evacuation orders if the fire is nearby.

Keep windows and doors shut. Stay cool and safe by using a high-efficiency filter in your air conditioner or room unit. If you don’t have air conditioning and it’s too warm inside, find shelter somewhere else. If smoke is persistent over time, the particles that get into your home can build up.

Avoid making the air quality worse. You could pollute it by:

  • Burning candles
  • Using a gas, propane, or wood-burning stove
  • Lighting a fireplace
  • Using aerosol sprays
  • Frying or boiling meat
  • Smoking tobacco
  • Vacuuming

Check air conditioners. Make sure the recirculation setting is on so it uses the air already inside your home, instead of pulling outside air in.

Consider buying a portable air cleaner or air purifier. Make sure it has a clean air delivery rate (CADR) that's sized for the room you want to use it in. The higher the CADR, the more particles it can filter and the bigger space it can clean. High-efficiency particulate air (HEPA) filters cause a higher CADR. If you want to remove gases from the air, look for a filter that can remove gases specifically -- like an activated carbon filter. Air purifiers with a high CADR and activated carbon filters can get rid of particles and gases. Also, check that the manufacturer says the unit doesn’t create ozone. Small air cleaning units may be good if you work in an office or want to run something in your vehicle while you drive.

Make a temporary air cleaner. The U.S. Environmental Protection Agency (EPA) warns that this shouldn't be a permanent solution. But you can make your own air cleaning system with a box fan, furnace filter, and some other household items.

Change filters in your air purifier often. Pay attention to how often you may have to change any filters -- like the HEPA filter -- in your air cleaning unit, if you have one.

Set up one room in your home to be a “clean room.” It should have no fireplace and few windows and doors. If you have a portable air cleaner, use it in here.

Use N95 respirators. These can protect you from airborne particles if they fit your face snugly and you wear them properly when you're outside. They’re sold online and at certain home improvement stores. Dust masks won't help filter out smaller particles. If you can't get an N95, masks with N-95 or N-100 filters may help. But they may not fit properly and can be hard for people to use if they have lung disease. 

Keep an eye on your kids. They may be more vulnerable to smoke.

Watch your pets. Your animals may have trouble breathing, watery eyes, runny nose, and be less hungry or thirsty. Keep them indoors in a well-ventilated space. Keep carriers handy in case you need to evacuate.

Before wildfire season:

If you have an existing health condition, it's a smart idea to prepare for wildfire smoke exposure.  

  • Ask your doctor to come up with an action plan of steps you’ll take to protect your health.
  • Keep a 7- to 10-day supply of your medications in a childproof, waterproof container to bring with you if you have to evacuate.
  • Buy groceries you can eat without cooking, since frying or grilling can pollute the air inside your home.
  • Stock up on food.
  • Keep your heating and cooling systems in good condition.
  • Buy a fan or portable air conditioner so you can stay cool without having to open windows. Know how to hook up the exhaust so it doesn't draw in outdoor air.
  • Consider buying a generator and know how to use it safely. 
  • Have an evacuation plan ready that includes caring for any pets.
  • Keep extra N95 masks handy.

After a wildfire:

  • Keep checking the air quality, since smoke can linger after a wildfire ends, even if it's not as visible.
  • Clean up using these tips, because ash can harm your health, too.
  • Call your doctor if you have symptoms that get worse or won’t go away.

If symptoms don't go away within a day or so, call your doctor.

If you see a doctor, they may do tests (including blood tests) to assess the damage from the smoke. They may put an oxygen mask around your nose so you can breathe in oxygen. 

For mild symptoms from pollution exposure like eye, throat, and nose irritation:

  • Get plenty of rest and sleep. 
  • Soothe a dry throat with candy or cough drops.
  • Take any medicine as prescribed or instructed.
  • Use a spirometer (a device to measure lung function) as directed.
  • Avoid smoke or other irritants.

It might, especially if the smoke hangs around for a long time or keeps coming back. But research on the links between wildfire smoke and mental health is still in its early stages. We need more studies to understand the possible effects better.

We do know that that the threat of wildfires themselves can take a toll on mental health. Research shows that living through one of these blazes makes you more likely to get conditions such as depression and posttraumatic stress disorder (PTSD).

Before, during, and after a wildfire, it’s common to:

  • Feel scared
  • Constantly worry
  • Sleep poorly
  • Have depression-like symptoms

Someone who’s been through a natural disaster like a wildfire might also:

  • Have nightmares, memories, or thoughts about it over and over
  • Worry a lot
  • Feel guilty for unclear reasons
  • Miss a lot of work or school
  • Eat or sleep too much or not enough
  • Avoid people or activities
  • Have less energy
  • Have lots of stomachaches or headaches
  • Feel hopeless or helpless
  • Drink or smoke too much, or turn to drugs

Reach out for help if you or someone you know has any of these symptoms for 2 weeks or longer. Talk to your loved ones, trusted friends, or your doctor. You can also get support and counseling by calling or texting the Disaster Distress Helpline at 800-985-5990. It’s confidential and available 24/7.

If you’ve thought about hurting or killing yourself or someone else, get help right away. Call 911 or the National Suicide Prevention Lifeline at 800-273-TALK (8255).

Show Sources


CDC: “Wildfires,” “Protect Yourself from Wildfire Smoke,” “Going to a Public Disaster Shelter During the COVID-19 Pandemic," "Wildfire Smoke."

U.S. Environmental Protection Agency: “How Smoke from Fires Can Affect Your Health," "Guide to Air Cleaners in the Home," "Why Wildfire Smoke is a Health Concern," "Wildfires and Indoor Air Quality (IAQ)," "Health Effects Attributed to Wildfire Smoke." “Wildfire Smoke Fact Sheet,” "Air Quality Index (AQI) Basics," "Protect Your Pets from Wildfire Smoke," "Fire and Smoke Map."

Washington State Department of Health: “Smoke from Fires.”

UCLA: “Review of the Mental Health Effects of Wildfire Smoke, Solastalgia, and Non-Traditional Firefighters.”

International Journal of Environmental Research and Public Health: “Chronic Mental Health Sequelae of Climate Change Extremes: A Case Study of the Deadliest Californian Wildfire.”

SAMHSA: “Wildfires,” “Warning Signs and Risk Factors for Emotional Distress,” “Suicide Prevention.”

United Nations: "How is air quality measured?"

Harvard University: "A Deadly Mix: Wildfires and Urban Air Pollution Create Toxic Ozone."

Stanford University: "Mitigating the health impacts of wildfire smoke."

American Lung Association: "Protecting Lung Health During Wildfire Season," "How Wildfires Affect Our Health."

USDA: "Wildfire Smoke and Your Health."

South Coast Air Quality Management District: "Wildfire Smoke & Ash Health & Safety Tips."

PBS: "How wildfire smoke can threaten human health, even when the fire is hundreds of miles away."

CAL FIRE: "Power Outage Information."

State of California: "Protecting Outdoor Workers Exposed to Smoke from Wildfires."

European Commission: "‘Four times more toxic’: How wildfire smoke ages over time."

Kaiser Permanente Health: "Smoke Inhalation: Care Instructions."

Oregon Health Authority: "Fact Sheet: Do It Yourself (DIY) Air Filter." 

California Air Resources Board: "Inhalable Particulate Matter and Health (PM2.5 and PM10)."

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