As Canadian wildfire smoke travels down to US, here's why it can be so dangerous
As hundreds of wildfires burn across Canada, Americans' health could be impacted.
As of Wednesday, 203 wildfires were burning in Canada, according to the Canadian Interagency Forest Fire Centre.
The smoke forced health officials in the U.S. to send air quality alerts across parts of the Upper Midwest on Tuesday and caused hazy conditions in New York, according to National Weather Service NY.
Readings from AirNow show air quality alerts in the Northeast, Midwest and Great Plains range from "moderate" to "unhealthy."
Inhaling toxic smoke and ash from wildfires could cause damage to the body -- including the lungs and heart -- and even weaken our immune systems, experts said.
"There's no such thing as safe wildfire smoke; any of it is too much for us. It's important that we get prepared and we're taking this seriously," Helen Christoni, an air quality expert and senior vice president of AirDoctor by Ideal Living, told ABC News.
What wildfire smoke is made up of
Wildfire smoke is a mixture of gases, water vapor, air pollutants and fine particulate matter, the latter known as PM2.5, which is at least 30 times smaller in diameter than a human hair.
Experts say these particles are of concern because they are too small to be seen with the naked eye and can easily enter the nose and throat and can travel to the lungs.
Some of the smallest particles even circulate in the bloodstream, according to the Environmental Protection Agency.
PM2.5 can cause both short-term health effects, even for healthy people, including irritation of the eyes, nose and throat; coughing, sneezing; and shortness of breath and long-term effects such as worsening of conditions such as asthma, heart disease or COPD flare-ups.
Vulnerable groups including children, pregnant women, older adults and those who are immunocompromised or have pre-existing conditions are at increased risk of having negative health effects.
"You don't want to be breathing heavy concentrations of these [particles]," Ian Shapiro, associate director of building science and community programs at Syracuse University Center of Excellence in Environmental and Energy Systems, told ABC News. "It could be an acute problem for somebody who's vulnerable, but just not healthy for anyone to be breathing."
Not all PM2.5 particles are the same. One study from California in 2021 found that those from wildfires can be up to 10 times more harmful than the same type of air pollution coming from combustion activity.
Shapiro said fine particles from a wildfire can travel large distances, affecting residents of other states or even other countries.
Christoni agreed: "Toxic substances and particulate matter from wildfires are sticky. They can adhere to surfaces for up to several years, with hundreds of miles from where that fire started."
How wildfire smoke affects health
Breathing in smoke can cause a host of symptoms right away including coughing; wheezing; itchy, watery eyes; headaches; runny nose; chest pain; and trouble breathing, according to the Centers for Disease Control and Prevention.
It can also increase the risk of exacerbation of asthma, bronchitis and reduced lung function, the EPA says. Additionally, smoke can cause cardiovascular effects including stroke, heart attack, heart failure and increased risk of premature death.
Christoni said exposure to wildfire smoke can also be correlated with neurological decline along with reproductive and mental health issues.
Cardiovascular and cerebrovascular emergency department visits in 2018 in California rose on smoky days, according to a 2018 analysis.
Additionally, a 2015 systematic review of studies involving wildfires and human health in communities found wildfire smoke was significantly associated with risk of respiratory morbidity, meaning diseases and conditions that affect the respiratory system.
Studies have shown a link between poor air quality -- which these wildfires have caused -- and cardiovascular disease, including strokes, heart attacks, heart failure and atrial fibrillation.
How to stay safe
Shapiro recommends running portable air cleaners equipped with HEPA (high-efficiency particulate air) filters, which can reduce airborne particulate concentrations within minutes.
"If you have particles in your home and you turn it on, you will immediately see a drop in the concentrations, a dramatic drop in the concentrations," he said.
Shapiro added that people should close windows and doors and limit the use of exhaust fans, which pulls outdoor air into a home.
If possible, Christoni encourages people to create a safe room in their home, where they can "seal everything up and run an air purifier" and eliminate breathing in any of the "volatile organic compounds" found in the smoke like benzine or formaldehyde.
Lastly, if air quality worsens, Shapiro recommends wearing a high-quality, well-fitting mask when outside to help filter inhaled particles.
