🔥 Thousands of deaths per year caused by an invisible gas from wildfires

Wildfires send huge plumes of smoke into the sky, but a far more insidious danger hides in their emissions: ground-level ozone. This secondary pollutant, completely invisible to the naked eye, causes thousands of deaths each year in the United States, without the general public grasping the scale of the phenomenon.

Unlike fine particulate matter (PM2.5), which is directly emitted by flames, ozone forms secondarily. When volatile organic compounds and nitrogen oxides from the fire interact with sunlight, they create this gas that irritates the lungs and heart. According to Minghao Qiu, a researcher at Stony Brook University, this ozone has long remained in the shadow of health studies.


By exploiting twenty years of satellite data and ground measurements, scientists were able to estimate the health impact of this ozone of wildfire origin. Result: on average, 2,045 additional deaths per year are attributable to it in the United States.

Some regions are particularly exposed. Southern states like Texas, Louisiana, Arkansas, Mississippi, and Florida accumulate more ozone during smoke episodes. This additional pollution nibbles away at the progress made thanks to the Clean Air Act, which had reduced ozone-related mortality in recent decades.

Researchers know that wildfire smoke also contains heavy metals like lead or aromatic hydrocarbons. Understanding how these substances act together on health remains a challenge. Minghao Qiu and his team are already preparing further studies, but federal budget cuts threaten this research. NASA and NOAA, which provide the essential data, risk losing more than a third of their scientific budgets.