Proven link between heart disease and ozone pollution, according to a study in China

Air pollution by ozone is associated with a rise in hospitalizations for heart disease, according to a study in China released on Friday, the latest illustration of the risks posed by greenhouse gas emissions.

This study, published in the European Heart Journal and covering 258 million people in 70 Chinese cities, compared hospital admission data over the period 2015-2017 with the live evolution of the quality of the air in these cities.

These data show that, independently of other pollutants, ozone was associated with more than 3% of hospitalizations linked to coronary heart disease, heart failure and strokes.

20x impact when levels exceed 200mg

In addition, each increase of 10 micrograms of ozone per cubic meter of air has been shown to be related to a 0.75% increase in hospitalizations for heart attacks and a 0.4% increase for strokes.

“While these increases appear modest,” the impact would be “magnified more than 20 times” when ozone levels exceed 200 micrograms during the summer, study author Shaowei Wu told AFP. from Xi’an Jiaotong University, and his colleagues. In this extreme example, theOzone exposure is linked to 15% of heart attacks and 8% of strokes, the researchers estimate.

While ozone in the upper layers of the atmosphere helps block harmful ultraviolet (UV) rays from reaching Earth, at ground level, this gas is a major component of the smog that pollutes most major cities. .

Ozone is created in the atmosphere by a chemical reaction when two pollutants, often emitted by cars or industry, combine in the presence of sunlight, and has been shown to interfere with photosynthesis and plant growth.

A call to implement an alert system

The study claims to be the first to assess the risk of hospitalization for heart disease when ozone levels exceed the daily recommendation of 100 micrograms per cubic meter of air issued by the World Health Organization.