Canadian wildfires are impacting air quality in the U.S. — an expert explains why that matters to public health

A yellowish haze descended upon New York last week as smoke from Canadian wildfires spread in wide swaths across parts of the Midwest and Northeast.

Expected above-normal fire activity in Canada could mean that smoke and poor air quality concerns will continue to impact northern parts of the United States throughout the summer. 

Roberto Lucchini, a professor of environmental health sciences in the FIU Robert Stempel College of Public Health and Social Work, studies environmental and occupational exposure to airborne particulates and air pollution. He discusses the science behind why breathing in smoke and other forms of air pollution can be a concern, how it impacts human health and ways to limit exposure. 

Why is breathing in smoke harmful to human health?

Smoke is a form of air pollution, and the composition of airborne particles generated by wildfires is similar to the other sources of pollution, like that from traffic and industrial and agricultural emissions.

What makes air pollution a concern is that it is made up of very tiny particles, and some can contain toxic heavy metals, like lead, cadmium and arsenic, which are not good to breathe in. Most are microscopic, between 10 microns to 2.5 microns. (For comparison, a grain of sand is about 90 microns and the diameter of a human hair is between 50 and 70 microns.) 

This captivating visual predicts how intense Canadian wildfire smoke will travel from June 7 to 9, and includes data from @NOAA/@NASA’s #SuomiNPP & NOAA’s #NOAA20 satellites.

Green, yellow and red represent dense smoke, seen swirling across the United States. pic.twitter.com/Nu6gxFsiYW

— Joint Polar Satellite System (JPSS) (@JPSSProgram) June 9, 2023

Particles smaller than 10 microns are easily inhaled and can go deep into the lungs, causing respiratory problems. They can irritate our airways, and the first effects can cause a cough. They also trigger an inflammatory response in our bodies, impacting not only the lungs but also the cardiovascular and nervous system. That’s why both the Environmental Protection Agency (EPA) and World Health Organization (WHO) have set limits on how much air pollution is safe to breathe. 

Even short-term exposure has been linked to decreased lung function, heart attacks and more. Cancer is another potential consequence. Incidence of the latter increased followng the collapse of the Twin Towers in New York City on 9/11, when a combination of jet fuel combustion and the smoldering of building materials together created toxic dust and fumes. 

What other forms of air pollution do we come across?

We come across air pollution every day. It's unavoidable. Construction sites generate dust, potentially impacting the health of workers and the surrounding community. Airports are a major contributor of air pollution, especially along flight trajectories. Traffic emission in high-populated areas without sustainable public transportation can also significantly affect air quality.

Who is most at risk?

Most at risk are the elderly, pregnant women and people with existing chronic conditions such as allergies or asthma. This can be observed in the increased number of ER admissions based on acute respiratory symptoms. If there’s repeated exposure, this can lead to long-term symptoms and exacerbate pre-existing conditions.

What can people do to protect themselves?

First and foremost, if impacted by hazardous smoke levels, limit your time outside and ensure all windows and doors remain closed. Sometimes harmful smoke particles can make their way into a home if there isn’t proper insulation. If possible, consider purchasing an air purifier to help keep your home free of outdoor pollutants.

As we have learned from the pandemic, personal protective equipment is key to protecting our respiratory health. especially during times when air quality is poor. If you have to venture out, masks can help filter out harmful particles. But it’s important to remember that not all masks are equal. For example, surgical masks are not sufficient to filter fine particles. The better recommendation would be a N95 mask.

Many of us can check our city’s air quality through our smartphone’s weather app. Is this a good way to monitor it?

Weather apps are becoming increasingly accurate but are still not sufficient in providing public health information. They don't really give an indication of what type of personal protective equipment to use and whether certain vulnerable populations should avoid leaving their homes. That’s why public health guidance should be provided to the public more extensively. 

More tips from the Centers for Disease Control and Prevention on how to stay safe from wildfire smoke.