A closely tracked global website ranked Chicago as the worst for air quality in the world on Tuesday owed to hovering smoke from Canada, where the drought-hindered fight against wildfires has persisted for weeks.
For comparison, Dubai, Jakarta, Doha, Indonesia, and parts of Pakistan, populate top poor-air rankings Tuesday. Detroit and Minneapolis also rank high, suffering under hazy, dangerous air from the north, where scientists say climate change, including extreme heat and drought, is worsening typical tendencies for wildfires.
According to IQ Air’s World Air Quality Index, Chicago’s skies Tuesday are considered an “unhealthy” 172. The reading has nosed even higher and looks to persist at least the rest of the day.
IQAir
The U.S.-based Environmental Protection Agency offers its own numbers-based and color-coded air-quality scale for severity.
The EPA’s air-quality index (AQI) ranges from 0 to 500. A higher level indicates a greater level of pollution and potential health concern. Levels under 100 are generally considered safe. Unhealthy levels range from 101 to 300, and more-sensitive groups, such as children, pregnant people, the elderly and those with underlying conditions, may experience respiratory distress at lower levels. Readings above 300 are dangerous for all.
Visit the EPA’s Air Now site for the latest readings around the country.
You can also examine longer-term air quality by select region.
And, the EPA offers some health tips for reducing your poor-air exposure risk, including the use of N95 masks.
By one estimate, even exposure to an AQI of 150 for longer than just a few minutes is equivalent to smoking seven cigarettes a day. And, since most cigarettes sold today are filtered, the consumption of wildfire smoke more closely resembles the impact of smoking unfiltered cigarettes.
Read: ‘Like unfiltered cigarettes’: Why is wildfire smoke so dangerous for the lungs?
Chicago has its turn
Fifteen of the past 30 days in Chicago have seen air qualities affected by Canadian smoke and the buildup of other pollutants. Such pollutants have been exacerbated by lake breezes which bring a layer of cooler air, which measurements have put at a depth of around 2,000 feet, creating a meteorological condition known as a temperature inversion, Chicago’s acclaimed WGN meteorologist Tom Skilling explained.
Read: Do smoky skies have you shopping for an air purifier? 5 things to know before you buy one
With inversions, instead of temperatures falling and air encouraged to “mix” vertically, a process which thins out pollution concentrations, temps instead hold steady or even rise. This essentially traps smoke and pollutants closer to the ground and leads to the unhealthful air quality, Skilling said.
Students exit a DePaul University building Tuesday covering their faces from Chicago’s acrid air, linked Tuesday to Canada’s historic wildfires.
Tim Rostan
Read: When air quality declines, low-income people and communities of color suffer the most
In Chicago and its suburbs, where some 9.5 million people live, the smoky experience follows days of Canada-linked hazy, orange skies in New York City and other parts of the populous U.S. northeast a few weeks ago. At that time, Manhattan and the other boroughs ranked as having the worst air in the world.
Aren’t wildfires typical? Yes, but the scope is worsening
As drought and extreme heat hit, this year’s wildfire season is the worst on record in Canada, with some 29,000 square miles burning across eastern and western Canada. That’s greater than the combined area burned in 2016, 2019, 2020 and 2022, according to the Canadian Interagency Forest Fire Centre.
For sure, wildfires are critical to maintaining a healthy, balanced ecosystem by keeping diseases and harmful pests at bay, clearing dead and overgrown vegetation, resupplying soil with nutrients and with a fire’s heat flashes, providing the necessary conditions for select new growth and habitats.
But manmade activity, including forestry budget cuts, human negligence and climate change are disrupting the natural fire ecology in many regions, says the National Interagency Fire Center. Although some wildfires occur naturally — sparked by lightning strikes, for instance — the vast majority of wildfires can’t be considered “natural.” Between 2018 and 2022, a period that featured record fires in California and the Pacific Northwest, 89% of wildfires were the result of human activity, the center’s data shows.
According to the nonprofit Environmental Defense Fund, increasing severe heat and drought due to climate change can fuel wildfires. Hotter temperatures evaporate more moisture from soil and vegetation, drying out trees, shrubs and grasses and turning leaf litter and fallen branches into kindling.
Dangerous emissions
In fact, Canadian smoke is even impacting Europe. Canada’s blazes have released a record 160 million metric tons of carbon, the European Union’s Copernicus Atmospheric Monitoring Service said Tuesday.
“The difference is eastern Canada fires driving this growth in the emissions more than just western Canada,” said Copernicus senior scientist Mark Parrington.
The carbon emissions the latest fires have released is roughly equivalent to Indonesia’s annual CO2 emissions from the burning of fossil fuels, such as coal, oil and gas
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And the loss of forests is costly, too. Forests act as a critical sink for planet-warming carbon. It’s estimated that Canada’s northern boreal forest stores more than 200 billion metric tons of carbon — equivalent to several decades worth of global carbon emissions.