With wildfires burning in North America, it’s important to know if you are enveloped in toxic smoke. The smoke is dangerous because it contains a mixture of hazardous gases and solid particles smaller than a human hair. According to the EPA, particulate matter, also known as PM 2.5, is a main component of wildfire smoke and is the air pollutant of greatest concern to public health. The fine particles are inhaled and enter your lungs and bloodstream where they can cause damage to other organs.
Intense heat from the fires pushes the smoke high into the atmosphere where it stays until it cools and begins to fall. Sometimes the smoke sinks to the surface. Either aloft or on the surface, strong winds can carry it long distances, even thousands of miles away. Smoke concentrations during a wildfire rapidly change, making it important to frequently monitor updates to smoke predictions.
Where wildfire smoke is in the US right now
As these tiny particles make it to the surface of the earth, they can also enter indoor spaces. There is good news, however: As smoke moves downwind, it generally becomes more diluted and widespread but less dangerous, according to Susan Stone, a senior environmental health scientist in EPA’s Office of Air Quality Planning & Standards. This means more people may be affected over a larger area but by less intense air pollution.
Even when smoke is visible in the atmosphere, the actual air quality reading might be lower than expected if the smoke is not concentrated near the ground.
The EPA monitors air quality near ground level where people breathe and relates the information to health effects you may experience within a few hours or days after breathing polluted air. The map below shows the level of PM 2.5.
Where the air quality is the worst right now
“Predicting if the air quality will improve or worsen can be difficult because of the unpredictable behavior of wildfires and factors such as wind, weather, and terrain,” according to an EPA course on air quality for health care providers.
In June and July of 2023, the majority of wildfires burned in Canada. But often, fires in California and the Western U.S. are more prominent. For the first seven months of 2023, California saw 22,000 acres burn. The five-year average for the same time interval is nearly nine times as high, according to CAL FIRE and the U.S. Forest Service.
Where wildfires are burning in Canada and the United States right now
Depending on what’s burning – grasslands, trees, vegetation or buildings – wildfire smoke can contain toxic chemical substances including carbon monoxide, carbon dioxide, acid gases, sulfur dioxide, nitrogen oxides, benzene, toluene, styrene, metals and dioxins, says the New York State Department of Health.
How toxic wildfire smoke affects your health
Breathing the toxic smoke can cause a series of problems, from minor irritations to serious concerns, including cardiovascular- and respiratory-related effects. According to Yale Medicine, the PM 2.5 particles are so small they can pass the usual defense mechanisms of the upper airway and penetrate deep into the lungs where they can impair function. The particles can also pass into the bloodstream and travel to other organs. Exposure has been linked to an increased risk of heart attack, stroke, lung cancer and a decline in cognitive function.
Here are six tips to reduce exposure to wildfire smoke and protect yourself from smoke particles
Contributing: Janet Loehrke and George Petras