Invisible ozone produced by wildfires contributes to more than 2,000 excess deaths each year among older adults in the US.
RT’s Three Key Takeaways:
- Invisible Respiratory Risk: Wildfire smoke significantly raises ground-level ozone, an invisible oxidant that triggers respiratory and cardiovascular issues even when smoke is not visible to the naked eye.
- Increased Mortality: Researchers estimate that wildfire-related ozone increases excess deaths by more than 2,000 per year in the US, with a primary focus on individuals aged 65 and older.
- Regional Air Quality: Daily ozone levels can rise by as much as 16% in parts of the Midwest and East, offsetting long-term national progress in reducing ozone pollution and improving public healthcare.
Wildfire smoke significantly raises ground-level ozone and contributes to more than 2,000 excess deaths in the US each year, according to a study published in Science Advances.
The research, led by Minghao Qiu, PhD, of Stony Brook University, indicates that while previous studies have focused on dangerous particulates emitted from fires, the impact of invisible ozone has been largely overlooked. Ozone is a strong oxidant linked to respiratory problems, cardiovascular issues, reduced cognitive performance, and increased mortality.
“As we move further into spring and then summer, wildfires will most likely increase in the United States and all of North America, and scientists should be thinking about the effects of increased ozone from fires in addition particulates emitted into the air,” said Minghao Qiu, assistant professor in the school of marine and atmospheric sciences and core faculty member of the program in public healthcare at Stony Brook University, in a news release.
The research team analyzed nearly two decades of surface ozone measurements, meteorological data, and satellite data from 2006 to 2023. Using machine learning models, they quantified changes in surface ozone concentration during fire episodes across the continental US. The team also utilized the National Oceanic and Atmospheric Administration (NOAA) Hazard Mapping System smoke plume product to compare ozone levels on smoke days versus non-smoke days while controlling for temperature and ultraviolet radiation.
The findings revealed that wildfire smoke boosts daily ozone by as much as 16% in certain regions, including the Midwest and the eastern US. This increase is significant enough to contribute to a rise in illnesses and deaths. The study specifically reported mortality data for populations ages 65 and over for consistency, estimating more than 2,000 excess deaths annually due to wildfire-related ozone.
Qiu noted that the total healthcare impact and death toll from wildfire smoke are likely higher than previously estimated because ozone exposure was not factored into prior research. Additionally, the study found that particulate matter and ozone pollution do not always overlap, meaning that even days with good visibility may contain harmful levels of unseen ozone.
“The true healthcare effects and death toll from wildfire smoke are likely higher than previously thought, given that prior research has not factored in ozone exposure,” said Qiu, in a news release.
The researchers also noted that the increase in ozone levels from wildfires acts as a hurdle to clean-air progress, partially canceling out long-term national declines in ozone levels and related mortality. The study was supported by the Minghua Zhang faculty career catalyst award and the NOAA Climate Program Office’s Atmospheric Chemistry, Carbon Cycle, and Climate Program.
