In 2013, Beijing’s dangerous air quality repeatedly made the news, on some days exceeding an average of 1,000 µg/m3 of fine particulate matter. Chronic exposure to the air pollutant is associated with early death, cardiovascular disease, and respiratory ills such as asthma attacks, among other health problems.
That year, the Chinese government began regulating emissions of fine particulate matter with a diameter of 2.5 µm and smaller, also called PM2.5. Now researchers led by Kebin He and Jiming Hao at Tsinghua University report that this regulation was effective. From 2013 to 2017, people’s annual mean exposure to PM2.5 in the country dropped from 61.8 to 42 µg/m3. The World Health Organization recommends no more than 10 µg/m3 annually. Still, the researchers estimate the country’s regulations prevented 370,000 deaths during the study period (Proc. Natl. Acad. Sci. U.S.A. 2019, DOI: 10.1073/pnas.1907956116).
By combining chemical transport modeling with a detailed study of emissions inventories, the researchers attributed the drop in PM2.5 to specific regulations put in place by the government. They found that three measures accounted for 92% of the improvement: regulating industrial emitters, such as power plants; phasing out outdated equipment; and promoting clean residential fuels. Air pollution is still a problem in the country, however. The researchers note that 64% of Chinese cities failed to meet national PM2.5 standards in 2017. They hope their analysis of what kinds of regulations are effective will help guide future policy, in China and other countries.