Even Healthy People Should Minimize Exposure to Wildfire Smoke, Experts Say

Air quality levels in some areas of the northeastern U.S. reached "very unhealthy" levels on Wednesday, prompting experts to urge everyone to remain indoors as much as possible.

"Generally, if you can avoid being outside, that's what we recommend," Sameer Khanijo, MD, a pulmonologist with Northwell Health in Manhasset, New York, told MedPage Today. "Walking to the car to get to work, things like that, we have to do. But going outside, biking, playing ball, swimming in the pool, you should try to avoid until the air quality gets a little bit better."

The source of the smoke-filled air is multiple active wildfires in Canada, many of which have been labeled as "out of control," according to Canadian officials. All that smoke is shifting down and lingering over much of the northeast.

On Wednesday afternoon, a federal air quality index topped 200 in New York, putting it in the range of "very unhealthy" -- mostly attributable to PM 2.5 levels, which are particulates that are extremely tiny, below 2.5 microns in size.

Khanijo said the smoke condition Wednesday afternoon was "more noticeable today than yesterday. The air is heavier, the skies are a little grayer. I can feel it in my eyes, I can feel it in my throat a little bit."

He noted that children, the elderly, and people with underlying medical conditions -- particularly respiratory and cardiac conditions -- are most at risk from wildfire smoke inhalation. Those with respiratory diseases such as asthma and chronic obstructive pulmonary disease (COPD) can experience exacerbations, he said.

"PM 2.5 can get into our mucus membranes and deeper into our lungs," Khanijo said. "What makes them more dangerous for people with an underlying condition is that these particles are small enough that they don't get filtered out by our hair or cilia. They can get deeper into the lungs and cause reactive airway disease."

People with respiratory conditions may experience difficulty breathing, coughing, or increased mucous production, Khanijo said. "They really should avoid being outside," he added. If they need to make essential trips, such as to the grocery store or pharmacy, they should ask another family member to do it for them instead, he said.

These patients should also be ready to use their as-needed medications such as rescue inhalers, albuterol, and bronchodilators if needed, he added.

Peter DeCarlo, PhD, an associate professor of environmental health and engineering at Johns Hopkins Whiting School of Engineering in Baltimore, agreed that "everyone is at risk from air pollution" and that children, the elderly, and those with chronic conditions are particularly vulnerable.

DeCarlo said he kept his two kids home from soccer camp, and has suspended his morning bike ride until PM 2.5 levels drop down into a more reasonable range.

"We associate respiratory conditions with air quality problems, but the reality is that it impacts our hearts and our brains and other body systems," DeCarlo said. "Those chemicals that we breathe in will deposit in our lungs, and then from our lungs via our blood, travel to all other parts of the body."

DeCarlo's expertise is in the chemical makeup of the gasses in the air we breathe. He said PM 2.5 is the major concern with wildfire smoke, which is a mix of organic material including black carbon or soot.

"It's essentially the same stuff that you get from the campfire or in your fireplace, just on a much larger scale," he said. "Basically, it's these tiny microscopic particles about 100 times smaller than the width of our hair, made up of chemicals that get into our lungs and then get deposited into the rest of our bodies."

Essentially, wood is cellulose -- a carbohydrate, particularly a sugar, made of carbon, hydrogen, and oxygen. Burning it adds oxygen, creating carbon dioxide. But most of the cellulose doesn't burn completely, he said, and that's PM 2.5, which is "mostly comprised of carbon, hydrogen, and oxygen. Many different products can be created from that fire condition -- thousands of chemicals -- but it's mostly the incomplete combustion of that cellulose."

DeCarlo noted that wildfires have become more frequent and robust on the U.S. west coast and in the mountain west, likely a result of climate change, and may intensify on the east coast as well.

"With warmer and drier conditions, we expect situations like this may be more common," he said. "It's not a great thing to be experiencing now, but it may become more frequent in the future."

He and Khanijo recommended wearing a mask -- mainly a well-fitting KN95 or N95 -- when going outside in the smoke.

Khanijo said he has not yet had to treat any emergencies among his pulmonology patients, but he said the next few days could bring more patients to emergency departments, particularly if conditions persist.

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