Wildfires are tearing through the forests of eastern Canada, and over the past few days, their smoke has drifted into much of the airspace in the northeastern US.
Almost everyone spending time outdoors has been sensing the change in air quality in their eyes and airways, and it’s a big strain on health.
“Particles, gases, volatile organic compounds in the air can cause inflammation in everyone,” said Daniel Croft, a pulmonologist and air quality researcher at the University of Rochester Medical Center in upstate New York. “This is a health risk for all people.” (Michael Kamali, who directs emergency medicine at the medical center, said in a press conference that there has already been an uptick in visits to urgent care centers and emergency rooms.)
As with any health risk, the threat is worse for some than for others — at least, in the short term. Smoky air is more likely to trigger acute and potentially life-threatening symptoms in people with lung and heart conditions. And certain people are likelier to breathe high doses of polluted air, making them more vulnerable to its effects.
These higher-risk groups might be the first to develop symptoms due to air pollution. With wildfire smoke now affecting parts of the world not used to seeing it, it’s worth knowing who’s at highest risk for acute symptoms, how to recognize red flags, and how to keep yourself safe. Here’s what you need to know.
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Who’s most likely to develop acute symptoms due to wildfire smoke?
Breathing polluted air affects the body in a few different ways. Larger pieces of particulate matter — tiny particles of soot and dust — can irritate the linings of people’s airways in their noses, mouths, throats, and lungs. And smaller bits, along with toxic gases and molecules called volatile organic compounds, can sneak from the lungs into the bloodstream, where they can travel to other organs and cause a wide range of short- and long-term problems.
Some people are more likely than others to develop symptoms in the minutes to hours following smoke exposure, said Croft. At the top of the list are those with chronic lung diseases that cause their airways to react more strongly when they’re exposed to irritants, or who have less lung capacity to compensate for episodes of lung irritation. This includes people with asthma and chronic obstructive pulmonary disease (COPD, often known as emphysema or chronic bronchitis). People with heart disease are also at higher risk, as the toxins in air pollution can trigger heart attacks or stroke.
According to the Environmental Protection Agency, older people, whose immune systems are less well equipped to deal with airway irritation, are also more likely to experience symptoms even if they have healthy hearts and lungs. Children are more likely to develop symptoms because they often spend a lot of time playing outside — and because their proportions are different from adults, they inhale more air per pound of body weight than big people do. And people who work outdoors are also at higher risk because they have so much more exposure time.
Pregnant people take more breaths per minute, which raises their risk of inhaling particulate matter on smoky days. Breathing in lots of smoke while pregnant has been associated with lower birth weights and higher rates of preterm birth, and there’s evidence suggesting there could be direct effects of the inhaled toxins on developing fetuses.
And because low-income people are more likely to have untreated heart and lung disease — and often have less access to preventive measures — they’re also at higher than average risk when air quality plummets.
What are the symptoms of air pollution-related effects, and when should you seek care for them?
Any number of symptoms can occur in people who breathe smoky air, regardless of their baseline health. Common ones are irritation of the eyes, nose, and throat, trouble breathing, and chest tightness. Although these symptoms are annoying, they’re concerning only in the sense that they indicate airway irritation, which if repeated and prolonged, can raise the risk for longer-term consequences of air pollution exposure.
People with asthma and COPD may have additional symptoms of exposure — usually the same ones they get in response to other triggers (like viral infections or allergens). Wheezers will wheeze, coughers will cough, and whatever other symptoms a person typically gets will be aggravated.
For those with asthma and COPD, medications used to treat episodic worsening of these conditions — albuterol for asthma attacks, for example — should also work to resolve symptoms triggered by smoke exposure. Albuterol may also be useful as “pre-treatment” before going outside (masked, of course) for people with these conditions. Croft recommends that during wildfire season, people who use these medications should do their best to ensure they have an ample supply so they don’t run out in the middle of a coughing or wheezing fit.
There are some red flags that suggest a person might need some extra medical care to get through smoke-related symptoms. One is being unable to catch your breath, which might feel like having such trouble breathing that you can’t speak. Another is coughing that doesn’t stop.
Low blood oxygen levels even when breathing normally — measured with home oxygen saturation monitors that clip onto the end of a finger, which many people acquired during Covid — are also a signal to seek medical care.
For people who use albuterol for quick relief of asthma or COPD exacerbations, it should raise concern if those medications stop working. And for those who occasionally check their lung function by blowing air into a peak flow meter, seeing an unchanged peak flow measurement after an albuterol dose is also something to look out for.
How can you reduce the health impacts of polluted air?
Staying indoors as much as possible with the windows closed is the best way to avoid breathing polluted air. Whether you’re in a building or in a vehicle, roll up the windows and turn on the air conditioning or the fan.
Central air conditioning units usually have an air filter built in, so turning it on will circulate most of the outside air past a filter before it enters your living space. Even in homes with central heating but not cooling, running the fan (with the heat off) circulates air past the furnace filter, which still improves its quality. Unfortunately, window air conditioning units don’t do much filtration — so while they might cool you down, they won’t do much to remove pollutants from the air.
Home air purifiers usually have finer filters than central air conditioning units, so can remove smaller bits of particulate matter from the air. These can be very helpful for removing smoky, sooty bits from indoor air, which may be particularly important for keeping people with lung and heart conditions safe. (Croft notes it’s important to turn off the ionizing function if your purifier has one, as this function can increase air levels of ozone, another lung irritant.)
And if you must go outdoors, use an N95 mask or one with even better filtration capacity, said Croft, and try to avoid strenuous exercise or other activities that would require you to take lots of deep breaths outdoors. There’s no need to avoid errands that don’t require lots of outdoor time, like grocery store trips, but limit outdoor playtime for children to the extent possible.
“There really is no safe level of air pollution,” said Croft. He uses the AirNow website or app to track air quality on a daily basis; as soon as the air quality metrics depart the safe green zone, he says, people should layer on all the protections they can. “Even at low levels of air pollutions, there can be harmful effects to the body.”
“Whether you have lung disease or not,” said Croft, “it’s important to just keep yourself safe.”