Climate change is erasing previous gains in air quality — fires are mostly to blame

/ Justine CalmaA biker at a street corner against an orange sky hazy with smoke.

A graph shows the air quality index value in the US between 2000 and now. A line shows how air pollution fell in the 2000s with regulatory policies that improve pollution. In the mid-2010s, the line starts to climb back upward as “climate change overcomes regulation.”

A graph shows a timeline from 2000 to 2021 on the X axis. On the Y axis, the Air Quality Index rises from “Good” to “Moderate” to “Unhealthy for Sensitive Groups” to “Unhealthy” to “Very Unhealthy to “Hazardous.” A line across the graph shows average maximum values for fine particle pollution rising from the range of “unhealthy for sensitive groups to “unhealthy.”

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That generally accounts for peak levels of particle pollution during specific events like wildfires. The health risks from sudden, brief periods of pollution are different than those linked to persistent exposures to pollution from living next to a busy freeway, for example. Health risks including problems related to respiratory and cardiovascular disease increase with chronic exposure.

“If you have, say, more fires but less pollution in the rest of the year, you’d see these acute effects increase, but they will be offset by decreases in chronic effects,” says Drew Shindell, a professor of earth science at Duke University who studies climate change and air quality but was not involved in the First Street report.

Shindell also points out that there’s still the opportunity to change the trajectories laid out in the report. Just like the Clean Air Act led to big improvements in air quality between the 1970s and 1990s, the US has the opportunity to act now. Cleaning up pollution is just going to have to look different than it used to for policymakers, both Shindell and Porter say.

“The job of somebody like an air quality regulator is changing because it used to be 100 percent of your attention would be on emissions from human activities — so you’d worry about power plants, and industry, and motor vehicles,” Shindell says. “We’ve done a good job of controlling many of these things. But we haven’t done a good job of controlling greenhouse gases.”

In other words, to get soot and smog under control, regulators will also have to prioritize slashing other pollutants — carbon dioxide and methane emissions that cause climate change. They’ll also have to think about things like forest management to better keep wildfires under control. That all links the local effects of air pollution to what’s going on in the wider world, on top of worrying about what your neighbors might be emitting. Last year, wildfires in Canada sent a plume of smoke down to the Northeastern US, causing New York City to briefly hold the title for worst air quality in the world.

To see historical data and forecasts for future air quality in your region, you can check out First Street’s online tool at It uses First Street’s peer-reviewed models for forecasting flood, fire, heat, and now, air quality risk. It’ll show how a property ranks compared to others in the US when it comes to local air quality, which sources of pollution are nearby, and how many days of poor air quality in the area to expect now and in the future.