Ask the Doctors by Eve Glazier, M.D. and Elizabeth Ko, M.D

It’s Important To Wear Masks To Protect From Wildfire Smoke

Dear Doctor: Is wildfire smoke really that dangerous? We’re in northern Idaho and our town has been handing out face masks, but I’ve heard they don’t really do much. What should I do to keep our family safe?

Dear Reader: The smoke from wildfires does indeed pose a significant health threat. This is true whether you live near an active fire zone, or are in a town or city hundreds of miles away. Wildfire smoke rises to high altitudes and can thus be carried great distances.

When wildfire smoke drifts to earth in urban areas, it mixes with existing pollutants and elevates ozone levels. The smoke itself contains billions of minute particulates, which can adversely affect heart and lung health. There is now enough data to make the connection between wildfire smoke and a worsening of respiratory conditions like asthma, chronic obstructive pulmonary disease and allergies, and an increase in heart attack risk. The very young, the elderly and the medically frail are at especially high risk.

Breathing the minute particles found in wildfire smoke can result in wheezing, coughing, congestion, sneezing, throat and lung irritation, runny nose, watery eyes, shortness of breath and chest discomfort. The particulates in wildfire smoke are so small, they can reach deep into the delicate tissues of the lungs and set off an inflammation reaction. Since the airways of people living with asthma, COPD and allergies are chronically inflamed, even low levels of ambient wildfire smoke can make their conditions worse.

To protect against wildfire smoke, stay indoors as much as possible. Make sure all windows, doors, skylights and fireplace flues are kept tightly closed. Air conditioners or HEPA filters will help. While you’re inside, minimize indoor pollution. That means no vacuuming or use of aerosol sprays, scents or candles.

Anyone who relies on a rescue inhaler should make sure to have one ready, plus a spare in case it’s needed. Whether you’re indoors or out, avoid unnecessary exertion. If you do go outside for any length of time, it’s recommended that you change into clean clothes when you return indoors to prevent particulates from getting into the indoor air.

It’s natural to turn to a face mask for protection. However, the type of mask that you use makes all the difference. Dust masks and bandanas are porous and will catch only the largest particles, like ash and debris. The only masks that are capable of blocking the fine particulates associated with wildfire smoke are masks that are rated N95 or N100. It’s important that these types of masks make a full and complete seal around the perimeter. Any gaps will allow particulates to enter and defeat the purpose. Also, please note that breathing with these types of masks can be strenuous. It’s recommended that you choose one outfitted with an exhalation valve, which also reduces heat buildup.

Be sure to monitor your local air quality. If the symptoms described above persist, seek medical care immediately.

(Send your questions to, or write: Ask the Doctors, c/o UCLA Health Sciences Media Relations, 10880 Wilshire Blvd., Suite 1450, Los Angeles, CA, 90024. Owing to the volume of mail, personal replies cannot be provided.)