Breathing In Wildfire Smoke Can Lead To Detrimental Effects On Health
For the more than seven million people in California’s Bay Area living through historic wildfires, it’s been hard to breathe for the past month. For 29 days the region has been under a “Spare the Air” alert, which means inhaling outdoor air presents a health hazard. Air quality is even worse in Oregon and Washington, and by this morning smoke had stretched all the way to the East Coast and even to Europe.
Wildfire smoke contains a variety of gases and particles from the materials that fuel the fire, including ozone, carbon monoxide, polycyclic aromatic compounds, nitrogen dioxide, and particulate matter- pollutants linked to respiratory and cardiovascular illnesses, according to a study in the Journal of the American Heart Association.
When a healthy person breathes in air tinged with smoke from the fires, they may feel a sting in their eyes, and when they cough, they may have trouble recovering their breath. But what happens to that same individual when they breathe smoky air for extended periods every year is still unclear.
“People were once exposed once or twice in a lifetime,” says Keith Bein, an atmospheric scientist at the University of California, Davis. “Now it’s happening every summer and for longer.”
In the United States, air quality is measured on a color-coded scale known as the Air Quality Index (AQI), which was established in 1977 as part of the Clean Air Act. Stretching from 0 to 500, the AQI is split across six categories—from good to hazardous. Its scale measures the levels of five major pollutants: ground-level ozone, carbon monoxide, sulphur dioxide, nitrogen dioxide, and particulate matter.
State and local agencies in cities with populations over 350,000 are required to report these levels daily. The pollutants are measured both by instruments on the ground and satellites that constantly collect information about what’s in the atmosphere—including the particles from wildfires.
Impact on the human body
“We know pretty well it causes eye irritation, cough, wheezing—people with asthma are more likely to have an episode,” says Irva Hertz-Picciotto, director of Environmental Health Sciences Core Center at the University of California, Davis.
“Wildfire smoke is a very complex type of air pollution,” says Sarah Henderson, an environmental health scientist at the University of British Columbia. “It has many different gases in it, and the composition of those small particles can be highly variable, depending on what’s burning [and] how hot it’s burning.”
Of particular concern, she says, is particulate matter 2.5 microns in diameter—also referred to as PM 2.5. Those small particles, and ones even smaller, are capable of penetrating deep into a person’s lungs. Henderson says the body responds by releasing the same immune cells it would deploy to attack a virus. Unlike a virus, however, particulate matter isn’t broken down by that immune response and results in long-lasting inflammation.
“That inflammation affects your lungs, kidneys, liver, and probably your brain,” says Henderson.
Wildfires are a growing health threat- 15 of California’s 20 worst fires have occurred in the past 20 years, and Henderson says more evidence is needed to show exactly how wildfire smoke affects organs after long-term exposure.
