How Wildfires Affect Your Health

Around the country this July, the skies grew hazy and the sun burned red, as the smoke of wildfires from California to Canada blew across North America. A TikToker from Utah, @mandeemo_4045, has shown the dramatic effect of the haze in her state.


@mandeemoe_4045#wildfire #smoky #utah #airqualityalert #fyp #oregonfire #gross♬ Fast – Sueco the Child

Another, @world_gone_wild, shared a series of harrowing scenes from the East Coast. 

@world_gone_wild#wildifre #connecticut #connecticutcheck #connecticutlife #massachusetts #maine #newengland #hazy #hazytiktok #wildfiresmoke #tennessee #redsun #haze♬ Smoke on the Water (2017 Remaster) – Deep Purple

As wildfires blanket the US  with smoke each year, health experts encourage taking extra precautions to reduce your exposure to pollutants caused by wildfires and other substances. On August 9, The UN released the Sixth Assessment Report, Climate Change 2021: The Physical Science Basis, which spelled out that scientists expect climate change effects to worsen  over the next 20 years.

One TikToker in New York, @ZeroWasteCreative, explained that she was wearing an N95 mask, while out buying more masks to protect herself from smoke particles.

@zerowastecreativeUnhealthy AQI is 50 and up. Yesterday we were chillin’ in the 170 range. #ClimateChange #Wildfire #NYC DontQuitYourDaydream #TikTokFanFest #Wellness♬ All Eyes On Me – Bo Burnham

This image below, from the National Oceanic and Atmospheric Administration (NOAA), shows wildfire smoke being blown away from fires in the West, back in June 2021. 

Smoke Fills the Sky Below the GOES East Satellite

To see a real-time, interactive prediction of wildfire smoke’s movement, click here

Wildfire smoke contains small particles similar to those found in other polluted air, which  wreaks havoc on your body when you breathe them in. These particles are  thought to trigger inflammation and oxidative damage, while worsening common heart and lung conditions. A study in Nature Communications suggested that wildfire smoke is even worse for health than pollution from other sources like traffic exhaust fumes, because it has caused higher hospitalization rates.

 Short-Term Wildfire Smoke Exposure Symptoms

Wildfire smoke primarily affects the respiratory system, heart, eyes and skin. Some symptoms you may notice when the air quality is low are:

Skin irritation

Itchy eyes

Scratchy throat

Trouble breathing


Runny nose

Faster heart rate



Little is known about how smoke interacts with medications. But be aware that many medicines can cause or increase some of the symptoms listed above. If you’re taking a drug that causes respiratory, dermatological or cardiovascular side effects, you might consider taking extra precautions to avoid triggering or increasing those symptoms. For example, eggs, soy, wheat and shellfish can trigger asthma in some people (See Lifestyle Changes and Asthma).

Be sure to check out your prescriptions and over-the-counter (OTC) cold medicines because many drugs, including cold medicines and corticosteroids, can aggravate high blood pressure, among other conditions. 

People at the highest risk are those with:

COPD (chronic obstructive pulmonary disease)


Heart disease



Pregnant women

Firefighters or other first responders with high regular exposures to air pollutants

To elaborate on what we know and how to reduce exposure, MedShadow spoke with Rob Scot McConnell, MD, a physician and environmental epidemiologist at the Keck School of Medicine, who has studied the effects of wildfire smoke on health.

MedShadow: How can wildfire smoke cause health problems? What’s in it?

McConnell: There’s 50 years of research showing that particles in the air are bad for us in many, many ways. We know that when [there are] wildfires, you get astronomical levels of these particles in the air. It increases mortality. It’s damaging to the heart and to the lungs and may increase asthma in children. It just has a huge burden on morbidity and mortality.

[Editor’s note: particles, which come from wildfire smoke as well as other sources of air pollution from cars and trucks, are small enough to enter the lungs and bloodstream and then damage your body.] 

MedShadow: How does wildfire smoke differ from other air pollution sources, like car exhaust fumes? 

McConnell: Wildfires are a wild card, so to speak, because they show up unexpectedly. They produce huge amounts of particles. The toxic effects of them are not as well studied as particles from industrial or vehicular sources. And it can be quite a toxic mix. It’s [from] wood and chaparral [leaves and vegetation] and biomass burning, but it also runs through communities and burns up plastics and automobiles. A lot of modern products produce a lot of toxins, if they aren’t meant to be burned. 

MedShadow: How can those particles affect your health during a wildfire?

McConnell: There are both acute and chronic effects. The acute effects are that people are more likely to die on really high air-pollution days. You see increased mortality in the days of, and on days a week or so after a heavy exposure. It particularly affects the people who are older or who have underlying diseases: chronic lung disease, heart disease or children with asthma. Children with asthma generally don’t die, but they get asthma exacerbations. You see increased hospitalization and clinic visits. It [creates] a big burden on the healthcare system.

MedShadow: How can the particles affect your long-term health?

McConnell: Every year now in California, we’re getting big fires and we have several weeks of quite high levels [of air pollutants]. So then you need to worry about the chronic effects. There’s good evidence that these chronic levels produce lung disease and heart disease, and they may cause asthma. 

We know that [the high levels of air pollutants] reduce lung function. We’ve done a lot of studies looking at lung function in children. And we see that the growth of the function of lungs is slower in children who live in high-pollut[ion] communities. As an adult, if your lung function gets low enough, it’s one of the biggest predictors of mortality. 

There’s actually an emerging body of evidence indicating that particles are also bad for the brain. There are effects on the brain, sort of neuroperformance and brain structure that you can see in adolescents. And in the aging, you see accelerated decline and increased incidence of dementia, or Alzheimer’s disease, in people who live in more polluted communities.

MedShadow: How can we reduce our risk of exposure?

McConnell: I’m always very cautious in what I advise people about exercise, because there’s so much evidence that exercise is really good for you. But in the context of a really high and relatively short-term particle exposure, it makes sense to reduce your exercise. The reason is that even a moderate level of exercise increases by fivefold your ventilation rate — the amount of air that you pull in. And so that increases the dose of particles to your lung by fivefold.

There’s increasing evidence that room air purifiers with high-efficiency air filters, can markedly reduce the levels of particle exposures indoors. Two years ago, we bought a couple of air purifiers. I bought one for a little exercise room with a treadmill, so on polluted days, that’s where I exercise.

MedShadow: What should we look for when  buying an air purifier?

McConnell: You have to be sure to use a high-efficiency particulate filter [in your purifier]. Some of these air purifiers use ozone to trap particles. You don’t want to use a particle filter with ozone [because while they remove some particulate matter, those add other pollutants to the air.]

Editor’s note: This interview has been edited for clarity and length.

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