Wildfires in Canada are impacting US air quality. Here's how to protect yourself.

Adrianna Rodriguez, USA TODAY
Updated ·4 min read

Intense wildfires in Canada’s western provinces continued blazing Wednesday, sending smoke southward and triggering air quality alerts throughout the United States.

More than 400 wildfires are burning across the country, about half of them out-of-control.

Wind has carried the smoke as far south as Maryland, Baltimore, Virginia and Pennsylvania, according to U.S. officials. The Environmental Protection Agency also issued a poor air quality alert for New England on Tuesday, a day after similar advisories were issued in parts of Illinois, Wisconsin and Minnesota.

What are the health effects of wildfire air pollution and how can Americans protect themselves? Here's everything to know.

What are air quality alerts?

Air quality alerts are indicators the air is unsafe to breathe for certain people. Alerts are triggered by a number of factors, including the detection of fine-particle pollution — known as “PM 2.5” — which can irritate the lungs.

Pollution is detected by a system of monitors on the ground “constantly taking measurements of the amount of chemicals and particles in the air,” said Susan Anenberg, professor and department chair of environmental and occupational health at George Washington University.

How does the atmosphere affect wildfire smoke?

Atmospheric dynamics can carry wildfire smoke through the air and allow it to travel long distances, said Anenberg, who also directs the GW Climate and Health Institute.

“It’s strange to think about how a wildfire event that’s several hundred miles away can affect the air quality here (but) it’s not a unique phenomenon,” she said.

Due to an area of low pressure hovering offshore and an area of high pressure over Canada, a northerly flow of air was funneling the smoke south into the U.S. from Canada, AccuWeather said.

How does air pollution affect human health? Who is at risk?

Fine-particle pollution can affect every organ of the body, Anenberg said.

Studies show particle pollution has been linked to various health problems, according to the EPA, including:

  • Premature death in people with heart or lung disease

  • Nonfatal heart attacks

  • Irregular heartbeat

  • Aggravated asthma

  • Decreased lung function

  • Increased respiratory symptoms, such as coughing or difficulty breathing

Air pollution can be particularly harmful for sensitive populations, Anenberg said, such as people who have preexisting medical conditions, older people, young children, or people who are pregnant.

“People with chronic lung disorders are most at risk for exposure to smoke … It is important to continue taking medications to keep disorders under control,” said Dr. Jorge Mercado, associate chief of pulmonary, critical care, and sleep medicine at New York University Langone Hospital in Brooklyn.

How to stay safe from air pollution

PM2.5 is a mixture of chemicals that change based on what’s burning, Anenberg said. It’s possible some of the wildfire plume may contain toxic compounds from metals and chemicals.

“This can be quite health damaging and it’s important to recognize that this isn’t (all) natural biomass being burned but built environment, too,” she said.

It’s important take precautions against poor air quality. These are some safety recommendations from the California Air Resources Board, the state's agency charged with climate change programs and air pollution control.

  • Monitor daily air pollution forecasts in your area

  • Avoid exercising outdoors when pollution levels are high

  • Stay indoors with the windows and doors closed

  • Set air conditioning units to “re-circulate” to prevent bringing in air from outdoors

  • Keep hydrated by drinking water

  • Avoid adding to air pollution by wood burning, lawn mowing, leaf blowing, driving, barbecuing, smoking, using hairspray or painting indoors

How can outdoor workers stay safe?

The best way to protect yourself from air pollution is to stay inside and run an air filtration system that will reduce exposure, health experts say.

But people who need to work outdoors may be exposed to unhealthy air quality for prolonged periods of time. There are some ways to reduce the risk of complications from exposure, Anenberg said, including:

  • Wearing an N95 mask

  • Taking frequent breaks

  • Reducing strenuous activity

It’s also important to monitor symptoms and seek medical care, if needed. As air quality continues to worsen, health experts urge Americans to take precautions against exposure.

“There’s little doubt that the extremely high levels of particulate pollution we have seen from these fires is killing many people in real time as we watch,” said Doug Brugge, professor and department chair of public health sciences at the University of Connecticut School of Medicine.

Contributing: Elizabeth Weise and Doyle Rice, USA TODAY; Associated Press. Follow Adrianna Rodriguez on Twitter: @AdriannaUSAT.

Health and patient safety coverage at USA TODAY is made possible in part by a grant from the Masimo Foundation for Ethics, Innovation and Competition in Healthcare. The Masimo Foundation does not provide editorial input.

This article originally appeared on USA TODAY: Canada wildfires spark US air quality health concerns. What to know.