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Does Wildfire Smoke Exposure Have Long-Term Effects?

California wildfire smoke

 Mario Tama / Staff / Getty Images

Key Takeaways

  • Exposure to wildfire smoke a few times a year does not typically lead to chronic or major illness in most people.
  • People with underlying respiratory illnesses are most likely to be affected by wildfire smoke.
  • An N95 respiratory mask offers the best protection against wildfire smoke if you must go outside.

The wildfires on the west coast continue to spread as California enters its sixth week of battling the devastating destruction. With more than two dozen wildfires blazing through the state, over 18,000 firefighters continue to fight the flames daily. The smoke from the west coast has made its way across the country, blowing across Michigan and the Great Lakes region, through the southwest in Missouri, Illinois and Kentucky, and ending in the mid-Atlantic. 

With at least 35 people dead and tens of thousands of people evacuating due to the wildfire damage, it’s important to know the ramifications of wildfire smoke on human health, both in the short and long term. 

Protecting Yourself From Wildfire Smoke

According to the Centers for Disease Control and Prevention (CDC), the best way to protect yourself is to "reduce your exposure to wildfire smoke, for example, by seeking cleaner air shelters and cleaner air spaces.” The CDC also suggests limiting outdoor exercise when it’s smokey outside, or opting for lower-intensity activities to reduce smoke exposure. 

Another option is to use a mask while outdoors. “The best thing is to stay indoors and avoid going outside and being exposed to the fires—but, if one does have to go outside, then wearing a mask is very important,” Reza Ronaghi, MD, a pulmonologist in the division of pulmonary, critical care and sleep medicine at the David Geffen School of Medicine at UCLA, tells Verywell. “However, not every mask is useful and an N95 mask is needed to provide the greatest protection.”

Regular surgical masks and face coverings that we’ve all been wearing to help fight against COVID-19 do not help protect against poor air quality due to wildfire smoke. “Only an N95 mask that has been fitted to the individual can provide a great seal that is needed to prevent smoke from getting in,” Ronaghi says. 

Are There Long-Term Effects of Wildfire Smoke on the Human Body? 

While the wildfires have caused immediate damage by gutting homes and towns, experts say that a few weeks of smoke exposure should not have long-term side effects for most healthy people.

“Being exposed to chronic fires and poor air quality over many years can lead to lung disease and emphysema,” Ronaghi says. “[However,] these have to be high doses of exposure and over many years of exposure—being exposed once or twice a year will not lead to any long-term major illnesses.”

Reza Ronaghi, MD

Being exposed once or twice a year will not lead to any long-term major illnesses.

— Reza Ronaghi, MD

Those with underlying breathing conditions, such as asthma, are usually affected the most. "The biggest problem we see is usually worsening of underlying asthma, which can be very serious, but also worsening of chronic obstructive pulmonary disease (COPD), as well as infections in the airways and lungs,” Christopher Worsham, MD, a pulmonologist and critical care physician at Harvard Medical School, tells Verywell. “It’s also important to consider who is at higher risk: unsurprisingly, people with asthma or other breathing problems, children, pregnant women, and the elderly tend to respond worse to smoke injury of this kind.”

According to Worsham, most people exposed to significant or frequent wildfire smoke will not develop a serious complication like COPD, but it is a possibility for some folks. He compares breathing in a lot of smoke over time to smoking cigarettes in volume.

“One of the major problems that people who smoke encounter is COPD," he says. "In America, that is often related to smoking, but worldwide, inhalation of the particulates in the air is the major cause of COPD. That means irreversible injury to the lung that can worsen over time.”

Unfortunately, lungs might not be the only body parts that can be affected by wildfire smoke. “There is likely an impact on other parts of the body; some studies have shown increased heart attacks and strokes,” Lakshman Swamy, MD, MBA, pulmonary and critical care physician at Boston Medical Center, tells Verywell. “Particulates from the smoke can be found in the blood and may cause issues with the lining of blood vessels, so I would certainly be aware of the potential impact on the rest of the body as well.”  

What Can You Do To Make Sure Your Lungs Haven't Been Affected?

It’s important to stay indoors during active fire seasons, to stay up to date with local health officials and their recommendations, and to stay up to date with the air quality in your area. “If you are going outdoors, it is important to protect yourself with appropriate masks like N95, and to wash clothes upon coming home, since smoke can stick on clothes,” Ronaghi says. “It’s also a good idea to go around the house and ensure that all openings and cracks are covered to prevent the particles from entering the house.” 

If you are experiencing symptoms like dizziness, vomiting, or coughing, you should seek medical care. “Shortness of breath is very concerning but may not be noticed immediately,” Worsham says. “The problem here is that the damage caused by the heat and smoke have a delayed reaction, resulting in swelling and other changes in your airways and lungs, making it hard to breathe some time after the exposure to smoke.”  

Wildfire Smoke vs. COVID-19

If you're experiencing respiratory issues of any kind during the pandemic, it might be difficult to discern whether you’ve contracted the COVID-19 or you’re suffering from wildfire smoke inhalation.

While both can interfere with your breathing, Ronaghi says there are major differences between smoke exposure symptoms and COVID-19 symptoms. “With smoke inhalation, you will likely develop burning in the back of the throat, runny nose, watery eyes and some shortness of breath that will usually go away once the exposure to the smoke has subsided—also, there will be no fevers,” says Ronaghi. “With COVID-19, you will typically feel weak and have generalized malaise, a sore throat, cough, and a fever.”

Still, it's best to err on the side of caution if you're unsure of what your symptoms could mean.

“If you may have been exposed to COVID-19, regardless of smoke exposure, you should call your doctor or a COVID-19 help line to figure out your next steps regarding quarantine and testing,” Swamy says. “If you're short of breath for any reason, you should seek emergency care.”

What This Means For You

Bottom line: If you've been exposed to wildfire smoke, you should start feeling better once you're out of the smoke. If you've had on-and-off smoke exposure and start to develop fevers, you should call your doctor to discuss COVID-19 testing.

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Article Sources
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  1. California Daily Wildfire Update. Cal Fire. September 23, 2020.

  2. NOAA. Hazard Mapping System Fire and Smoke Product.

  3. Centers for Disease Control and Prevention. Wildfire Smoke and COVID-19. Updated August 25, 2020.

  4. Wettstein ZS, Hoshiko S, Fahimi J, Harrison RJ, Cascio WE, Rappold AG. Cardiovascular and cerebrovascular emergency department visits associated with wildfire smoke exposure in California in 2015. J Am Heart Assoc. 2018;7(8). doi:10.1161/JAHA.117.007492