• Posted January 30, 2024

Ozone-Linked Deaths on the Rise Globally

Deaths related to ozone air pollution will rise significantly around the world during the next two decades due to climate change, a new study warns.

Cities in North America, Europe, Asia, Australia and Africa can expect to see ozone-related deaths increase by as many as 6,200 fatalities a year by 2054 unless humans rein in global warming, researchers project.

"This paper is further evidence of the health benefits that can be achieved if more countries adhered to the Paris Climate Agreement's goals,"said senior researcher Kai Chen, an assistant professor of public health at the Yale School of Public Health in New Haven, Conn.

In the study, researchers analyzed short-term exposure to ground-level ozone pollution and daily deaths in 406 cities across 20 countries and regions. They used four specific climate change scenarios to predict future death rates due to air pollution.

Ozone is the primary component of smog, and it has been linked to respiratory problems, heart disease and premature death, researchers said in background notes.

Ozone forms when pollutants emitted by cars, power plants and industry chemically react in the presence of sunlight. Ozone is most likely to reach unhealthy levels on hot, sunny days in cities, according to the U.S. Environmental Protection Agency.

Researchers estimated that ozone-related deaths will claim as many as 6,200 lives a year in those cities by 2050-2054, up from an average 45 deaths annually in 2010-2014.

However, they also found that strong climate and air quality controls could make a difference.

In the scenario where nations stuck to the Paris climate accords, ozone-related deaths only increased by a projected 0.7% between 2010 and 2054, researcher said.

On the other hand, weak climate or air pollution controls led to an increase in ozone-related deaths of 56% to 94%.

All scenarios except compliance with the Paris accords led to an increase in mortality fractions -- the number of ozone-related excess deaths divided by total deaths.

"In all four of the climate scenarios we studied, only the scenario that aligns with the Paris Agreement would see a reduction in ozone-related mortality fraction in the future,"Chen said.

The new study was published Jan. 23 in the journal One Earth.

The researchers noted that many countries' climate and air quality standards fall short of what is needed to stem this tide.

In the most optimistic scenario for human health, researchers set the threshold for maximum allowable exposure at 70 micrograms of ozone per cubic meter of air.

By contrast, the World Health Organization's current air quality standard is 100 micrograms, researchers said. The standard is 137 in the United States and Mexico, 160 in China, and 120 in Europe.

"Our study highlights the need for more rigorous ozone standards,"the scientists concluded in a Yale news release. "Beyond mitigating ozone-related acute excess mortality, the implementation of stricter air quality regulations will likely yield additional benefits in terms of reducing long-term ozone-related mortality and conferring climate benefits."

More information

The U.S. Environmental Protection Agency has more about ozone pollution.

SOURCE: Yale University, news release, Jan. 25, 2024