US cities currently have the worst air quality in the world: here’s how to stay safe

Much of the United States is shrouded in smoke. Wildfires burning across Canada have sent plumes of air pollution toward the Midwest and Atlantic coast. At the time of writing, Chicago, Detroit, and Washington, D.C., topped the rankings of worst air quality in the world.

Smoke has serious health consequences. Even remote wildfire smoke can be dangerous to human health, perhaps much more so than other forms of air pollution.

In one Study 2021researchers analyzed hospitalizations for respiratory problems in Southern California and determined that exposure to particles contained in forest fire smoke appears to be 10 times more dangerous than exposure to other forms of particles of the same size, smaller than 2.5 microns, which is small enough to enter the bloodstream. It’s unclear whether the smoke is much more dangerous because of its unique chemical composition, the way it burns, or for some other reason, the authors write.

On supporting science journalism

If you enjoy this article, please consider supporting our award-winning journalism by subscribe. By purchasing a subscription, you are helping to ensure the future of impactful stories about the discoveries and ideas shaping our world today.

And in a February study, researchers estimated that between 2006 and 2020, wildfire smoke caused more than 24,000 deaths per year in the United States. The authors wrote that there was “no evidence of a ‘safe’ threshold” for exposure to wildfire smoke — any exposure corresponded to an increase in all-cause mortality.

As smoke from wildfires spreads vast distances, it can react with sunlight and urban air pollutants. produce ozonea main ingredient of smog. In a June study published In Science, Researchers have estimated that the number of deaths from ozone produced by wildfires has increased by more than 300 on average each year since 2013.

Some data suggests that wildfire smoke, like air pollution in general, puts a strain on mental health. As Scientific American reported By 2023, wildfire smoke, smog, and other toxic air have been linked to lower test scores among schoolchildren and higher rates of stress and depression. But these types of studies are rare, and it’s unclear what exact effect wildfire smoke has on the brain.

What is clear, however, is that climate change has made wildfires both more frequent and deadlier. Droughts and heat waves have become more frequent and more severe, leading to more dry vegetation at risk of burning.

As dangerous as wildfire smoke is, there is several ways you can stay safe. The United States Environmental Protection Agency recommended people stay indoors in accordance with local advisories, keep windows and doors closed, and consider using an indoor air filter if possible.

People with underlying conditions such as asthma and heart disease or pregnant women, as well as children, are at increased risk and should use extreme caution, according to the U.S. Centers for Disease Control and Prevention.

If you go out, the CDC recommends wearing an N95 mask or P100 respirator for better protection. Avoid exercising outdoors: What this means for this weekend’s World Cup final remains to be seen.

Experts also recommend check the air quality index in your area (AQI) to understand what weather conditions are like near you. Here is a useful guide on how to read the AQI.