When wildfires scar the landscape, they create huge clouds of toxic smoke that tint the skies orange and red. People with allergies may see wildfire smoke from a different perspective; those red skies can signal the start of an onset of allergic reaction and breathing difficulties.

What’s in wildfire smoke?

Wildfire smoke contains both gases and particle matter (solid particles).

PM2.5 and ultrafine particles are types of particulate matter found in wildfire smoke. They’re differentiated by size; for example, PM10 is coarse particulate matter measuring 10 micrometers in diameter or less.

However, while PM10 is a health threat, it is larger and less dangerous than PM2.5 and ultrafine particles, which are 2.5 micrometers in diameter or less and 0.1 micrometers or less respectively. These pose the greatest threat to human health, and they are the most commonly experienced pollutants. PM2.5 and ultrafine particles are so tiny they can enter the blood stream after being inhaled and reach all parts of the body.

In addition to solid particulates, harmful gases are also found in wildfire smoke. These gases range in adverse human health impacts from eye, nose, throat, and skin irritation to severe respiratory infection, asthma, and, in some cases, can be fatal. Gases included in wildfire smoke can include:

• formaldehyde
• benzene
• nitrogen monoxide
• carbon monoxide

High levels of formaldehyde and benzene exposure may lead to cancer, while breathing carbon monoxide can lead to poisoning and death (1).

Can wildfire smoke affect allergies?

Research has demonstrated that allergy sufferers, who often already have chronically inflamed airways, experience worsened symptoms during wildfire events (2).

In a 2022 study published in the International Journal of Environmental Research and Public Health, researchers found that respiratory peak flow among allergy clinic patients was decreased one year after exposure to two different wildfire events (3). Researchers noted the effect could be explained by the possibility that wildfire smoke increased allergic response to other allergens or that the smoke was causing a delayed immune response.

In a review of literature focused on the effects of wildfire smoke and exposure for people with asthma and allergic disease, a 2023 paper published in Current Allergy and Asthma Reports found that exposure to PM2.5 increases allergic predisposition and upper airway or sinonasal disease (4).

Government health organizations noted a number of additional chronic conditions that can be aggravated by wildfire smoke exposure, including asthma, heart disease, chronic obstructive pulmonary disease (COPD), and other respiratory diseases (5)(6). For anyone more vulnerable to wildfire smoke, planning ahead before wildfire season and wildfire smoke events is a key factor protecting your health.

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Symptoms of wildfire smoke allergies

While everyone exposed to wildfire smoke can struggle to breathe, allergy sufferers experience the same symptoms on a much worse scale.

Short-term effects of wildfire smoke exposure that could impact allergy sufferers include (7):

• Nose and throat problems
• Burning and watery eyes
• Shortness of breath
• Wheezing
• Chest pains
• Serious coughing
• Extra phlegm which traps air

Firefighters may experience respiratory system allergies through frequent exposure to smoke.

The takeaway

Wildfire smoke poses a real threat to your allergies and health, but you have several options for protecting yourself.

• If there is an active fire near your home, it may be advised to evacuate. Pay attention to local emergency alerts in the event an evacuation is advised.
• Receive real-time air quality alerts from a free air quality app so you can be prepared when wildfire smoke affects your neighborhood.
• Close doors and windows.
• If your HVAC is set to fresh air intake, close the outdoor intake damper or set the system to recirculate.
• Run a high-performance air purifier for wildfire smoke.
• Avoid exercise both indoors and outdoors.
• Avoid going outdoors.
• If you must go outside, wear a KN95/FFP2 mask to reduce exposure to particulate matter.