Increase in deaths attributed to ozone

Rising ozone pollution has emerged as a major health risk in China’s cities, causing a rise in deaths among vulnerable residents, according to Chinese researchers.

Data from 272 cities between 2013 and 2015 showed “robust evidence” linking rising short-term ozone exposure with increased mortality from cardiovascular and heart diseases as well as strokes, according to a paper published in the Environmental Health Perspectives journal.

Ground-level ozone, also known as photochemical smog, is caused by the interaction of sunlight with nitrogen oxides and the volatile organic compounds produced by burning fossil fuel or producing chemicals.

In China’s war on pollution, much of the focus has been on reducing concentrations of small airborne particles known as PM2.5, especially in winter.

Kan Haidong, director of the public health department at Shanghai’s Fudan University, said that while PM2.5 is currently a bigger contributor to China’s overall disease burden, ozone is already equally significant in regions such as the Pearl River delta.

“Ozone has been increasing in the past several years in China,” said Kan, who was involved in the study. “In contrast, PM2.5 has decreased by about 30 percent in the past five years.”

China’s average ozone exposure increased 17 percent over 2014-2017, implying an additional 12,000 premature deaths per year, Greenpeace estimated, using data from China’s environment ministry and the Global Burden of Disease database.

China launched a 2013-2017 action plan aimed at reducing average PM2.5 levels by 25 percent in targeted regions, but there was no target for ozone.

Liu Bingjiang, head of the environment ministry’s air quality department, said in September that 59 out of 338 monitored cities exceeded the national ozone standard of 160 micrograms per cubic meter last year.

But he said recent increases were “still a normal fluctuation.”