Fine particle pollution declined rapidly following the implementation of new rules on industrial emissions and the promotion of clean fuels, according to the study, published Monday in the journal Proceedings of the National Academy of Sciences of the United States of America (PNAS).
The study, which focused on the period from 2013-2017, was conducted by a group of Chinese researchers and scientists.
PM2.5 particulate matter, as this kind of pollution is known, is so small that it can enter the bloodstream, potentially leading to cancer, stroke and heart attack in the long term.
After rapid industrialization and weak regulations left the country with a reputation for smog and bad air quality, Chinese authorities started to take air pollution seriously in 2008.
In 2013, Beijing had PM2.5 concentrations 40 times higher than levels recommended by the World Health Organization (WHO), and the government introduced its toughest-ever clean air policies that year.
The study found "significant declines" in PM2.5 levels across China from 2013-2017, coinciding with new standards for thermal power plants and industrial boilers, the replacement of old factories, and new emissions rules for vehicles.
While the weather can also influence PM2.5 concentrations, the study found it had relatively little impact for the period of the study.