Increase in wildfire-driven ozone linked to premature deaths across the U.S.
Smog linked to wildfires is getting worse across much of the U.S., playing a role in more than 300 additional premature deaths every year since 2013, researchers say.
The main ingredient in smog is ozone, which is a gas molecule made of three oxygen atoms that, depending on where it forms, can be either helpful or harmful. In the layer of the upper atmosphere called the stratosphere, the gas creates a protective layer that shields Earthlings from harmful ultraviolet rays. But ozone is dangerous when inhaled. So on the ground, the gas can lead to respiratory issues , particularly in people with asthma or other breathing conditions.
This ground-level ozone can form when carbon monoxide gas emitted by wildfires chemically reacts with nitrogen oxides in the presence of sunlight. Wildfires have been on the rise because of climate change , according to NASA. To get a full picture of the effect of this recent increase in wildfire frequency and intensity, a team of researchers fed surface ozone levels and premature death data into a deep-learning model.
The new analysis, funded by NASA, showed that, between 2003 and 2015, ground-level ozone decreased, likely resulting from tightened controls on ozone-forming chemicals released by human activity, such as car tailpipe emissions, the scientists said. Those gains were reversed between 2015 and 2024, when, the model showed, ozone levels increased, particularly in the Midwest and parts of the western U.S.
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