How Wildfire Smoke Affects Your Lungs

It’s wildfire season out West. Coughing, wheezing, shortness of breath and worsened symptoms of chronic respiratory conditions from smoke exposure are leading to increased visits to emergency rooms and urgent care centers. If you live within range of wildfire smoke, it’s important to protect your lungs.

Carbon monoxide, sulfur dioxide and nitrogen oxide are just some of the unhealthy gases contained in wildfire smoke. Exposure to pollution from particulate matter — particles suspended in the air — is a prime wildfire health concern.

Although risk is higher for certain vulnerable groups, everyone can be affected if area air quality is bad enough. Respiratory health experts in four hard-hit states explain how to protect yourself from the ill effects of wildfire smoke.

Common Smoke Symptoms

Encounters with smoky air can lead to respiratory and other symptoms:

— Cough.

— Upper airway congestion.

— Nasal congestion.

— Sore throat.

— Itchy, burning eyes.

— Hazy vision from eye irritation.

— Headaches.

— Heart racing.

Severe Symptoms

If you have an underlying lung condition, smoke sensitivity can worsen, or exacerbate, these symptoms:

— Shortness of breath.

— Bronchospasm, or muscle-tightening and narrowing of your airways.

— Wheezing.

Asthma flares.

— Chest tightness or sensation of suffocation.

— Increased cough with sputum production.

— Increased use of medications for asthma, COPD or related conditions.

[Read: Montana Physician Truly Heads Toward the Fire.]


So far this week, the air quality index is mostly good or moderate in Oregon, but unhealthy for sensitive groups in areas near wildfires such as Madras and Cave Junction.

Wildfire smoke in Oregon is “pretty bad,” says Dr. Gopal Allada, an associate professor of pulmonary and critical care medicine in the Oregon Health & Science University School of Medicine. “I’ve lived in Portland 20 years and I can say this is the worst we’ve had.”

Typically blue skies have now turned brown and gray. Last week, Allada said, the situation earned the city an unenviable distinction: “We’re worst in the world for air quality for all major cities across the world.”

Even so, persuading activity-loving residents to avoid venturing out into smoke-tinged air is a challenge. “Portlanders and Oregonians are such outdoorsy people that they’ll try to do it,” Allada says. “But when you exercise or do something physically active outdoors, you actually breathe in a lot more air per (each inhalation). So it puts you at higher risk to do that now.”

Wildfire smoke contains high concentrations of the tiny PM2.5 particles, which means particulate matter with a diameter of 2.5 microns or smaller. These particles are “really adept at getting into the deeper parts of the lungs and causing and triggering inflammation and subsequent symptoms,” Allada notes. He is concerned about higher-risk patients with chronic lung disease who could have a flare of their underlying problem and end up in the emergency room or admitted to the hospital if they’re exposed to smoky air for long.

High-quality, hospital-grade N95 masks can provide protection from harmful air particles, Allada says. The catch is that during the COVID-19 pandemic, N95s are in critically short supply and ideally should be prioritized for health care workers on the front lines. And although scarves and bandannas can be used for coronavirus protection, he says, “Now, enter the wildfires, and those particular masks do not screen for that small, particulate matter.”

Wildfires provide another powerful reason to stay home, Allada says. “We actually cancelled in-person clinic visits in our ambulatory center and transitioned (patients) to telehealth, just because we didn’t want people to get outside and drive up under those conditions — because that in and of itself is a danger,” he says. “So we’re trying to do our best to accommodate our patients and protect them, as well.”

Outdoor Precautions

Life goes on and it’s not always possible to shelter from smoke indoors. When you must go out, take these precautions:

— Limit outdoor exposure as much as you can.

— Balance healthy outdoor exercise benefits with harmful smoke risks.

— Check the current air quality index in your area.

— Reduce outdoor activity when the AQI is high.

— Wear a high-quality N95 mask if you have one.

[See: Personal Protective Equipment (PPE): Definition and Examples.]


Last week, Dr. Cora Sack, a pulmonologist with UW Medicine in Washington, was checking the prolonged weather forecast and looking for rain. Just a few days ago, air quality was reaching unhealthy to hazardous levels in parts of the state.

“Seattle is a little better than eastern Washington right now,” says Sack, who is also an assistant professor in the departments of medicine and of environmental and occupational health sciences at the University of Washington. “It’s certainly still very smoky.” Thankfully, rain and thunderstorms helped clear the smoke over the weekend, and the AQI is now good throughout much more of the state.

Although you’re far safer indoors when it comes to wildfire smoke, you’re not completely out of the woods. “There’s definitely infiltration of outdoor air pollution to inside,” Sack says. “A lot of houses are older and leaky.”

This is a good time to check the filter rating on your HVAC unit. The MERV (minimal efficiency reporting value) system reflects an air filter’s ability to capture larger particulate matter between 3 and 10 microns in diameter, which also occur in smoky air. For increased protection, a HEPA (high efficiency particulate air) filter can capture more airborne particles.

Unfortunately, some people don’t have access to clean indoor air. Pandemic restrictions pose a new barrier that wasn’t present in previous wildfire periods. “Usually, we try to open clean-air shelters for people who don’t have a place to go,” Sack says. “That is very difficult with the need to balance social distancing and the risk of COVID transmission.” Now, previously available public clean-air spaces like libraries are closed, she notes.

To keep indoor air as clean as possible, The Puget Sound Clean Air Agency offers instructions on making an inexpensive DIY home air filter.

It’s important to keep personal risk in perspective, Sack emphasizes. “Wildfire smoke is very visible,” she says. “When you can see and taste the air it becomes a scary hazard, and there have been dangers shown in a lot of studies.” However, she adds, “Individuals should know that the relative risk of developing serious complications from wildfire smoke is still very low.”

On the population-wide level, Sack says, “We should be working on public policies to reduce severity of fires in the future.”

Indoor Safeguards

Staying inside is your best bet with wildfire smoke in the environment, particularly if you’re in a vulnerable group. Consider asking about telehealth options for doctor’s office visits. And take these steps to keep indoor air pristine as possible:

— Close windows and doors.

— Run HVAC systems on the recirculation settings.

— Install high-quality HVAC filters.

— Consider adding a HEPA filter.

— Use a stand-alone air purifier unit to create a “clean” room.

[See: 10 Questions Doctors Wish Their Patients Would Ask.]

Air-Quality Ratings

The air quality index is the Environmental Protection Agency’s system for reporting air pollution. A rise in AQI means higher levels of air pollution and increased health concerns. To get up-to-the-minute air quality ratings, simply plug into the interactive AirNow website. The color-coded AQI encompasses six categories ranging from “Good” green to “Hazardous” maroon. It’s a simple way to check whether air conditions are safe before you venture outdoors.


Pine needles and ash covering the ground — that’s what Dr. Robert Janata, a pulmonologist with UCHealth in Northern Colorado, sees from his patio when he steps outside his home in the Longmont, Colorado, foothills. Even the grass is ash-tinged. Smoke had been waning but now it’s back on the rise. Haze is in the air and it’s hard to make out mountains only 15 miles away.

On Monday, the AQI for Denver, Boulder and Fort Collins, Colorado, was unhealthy for sensitive groups with PM2.5 as the primary pollutant. “At our outpatient clinic, over the past few weeks, we’ve definitely seen a significant increase in calls for respiratory symptoms,” Janata says. Coughing and shortness of breath are common complaints, he says, and people are also noticing a lot of upper airway congestion, and itchy, burning eyes.

When it comes to preventing these symptoms, Janata says, “First and foremost is trying to limit exposure, which is difficult to do if anyone has to go do anything. Other than staying home, it’s trying to limit the going outside.”

Medications have a role in treating persistent, smoke-related respiratory symptoms, Janata says. The clinic is using more bronchodilator drugs like albuterol, which eases breathing by widening the airways, and increased inhaled steroids for patients with conditions like asthma, among other medications as indicated. However, he adds, “All those medications have a limited effect when the particulate materials are so significant these days.”

Patients with chronic lung conditions such as severe asthma, emphysema, bronchitis or chronic obstructive pulmonary disease are at significant risk of having a flare or exacerbation if they were to go out on a bad air quality day, Janata notes.

“For those at-risk individuals, I would really encourage watching your symptoms,” Janata says. “If you have shortness of breath, if you feel like you’re having an exacerbation, definitely seek out medical care and consider a visit to a physician or an emergency room if you’re in any significant distress.”

Vulnerable Groups

Wildfire smoke can affects anyone, but certain groups are particularly vulnerable:

— Chronic lung disease — asthma, COPD, bronchitis, emphysema — patients.

Heart disease patients.

— Children.

— Older adults.

— Pregnant women.

— Homeless people — who may have underlying health conditions.


On Monday, the AQI for parts of California nearest wildfires was unhealthy for sensitive groups with PM2.5 as the primary pollutant. You can still smell the smoke in areas like mountain trails, but Southern California skies are getting a little clearer, says Dr. Zab Mosenifar, a lung specialist and medical director of the Women’s Guild Lung Institute at Cedars-Sinai in Los Angeles, where the AQI is now moderate.

“The No. 1 advice to people who have underlying lung disease: It’s really imperative that they take their medications that their physicians have prescribed,” Mosenifar says. That includes patients with congestive heart failure as well as those with asthma or COPD.

Because children’s lungs are still developing, they also may be at higher risk. Although it might be harder to persuade kids to stay indoors, it’s worthwhile. “Keep children away from outside activities and any place that you smell smoke,” Mosenifar cautions. “Lungs grow to age 18.” It’s likely that some adult lung disease may be related to exposure to certain fumes and irritants during early childhood, he adds.

Pets suffer from smoke exposure, too. “Dogs and cats are very sensitive,” Mosenifar says. “Birds are extremely sensitive to smoke. The slightest amount of increasing carbon monoxide levels in the air and sulfur dioxide irritates them and really harms them.” So keep pets indoors as much as possible.

Mosenifar, who is an “avid” runner, still takes to the trails in the Santa Monica area. During wildfire season, he protects his nose and mouth with an N95 mask and a wet cloth to avoid inhaling particles, and often runs in the early morning when the smoke is a bit less intense. But his bottom-line advice for the public is: Stay indoors and minimize outdoor exercise, not only for yourself but also for kids.

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