New research indicates that long-term exposure to air pollutants, especially fine particulate matter such as PM2.5 and nitrogen oxides, may be an important factor in increasing the risk of cardiovascular disease.

The research was conducted jointly by Chinese and US institutions and universities including Fuwai Hospital of Chinese Academy of Medical Sciences in Beijing, University of Washington, State University of New York at Buffalo, UCLA and Emory University, Beijing-based news site Caixin.com reported on Thursday.

For the study, researchers recruited 8,867 suspected coronary artery disease patients aged 25 to 92 from North China who underwent coronary artery CT examination at Fuwai Hospital between November 2015 and September 2017.

The study found that exposure to air pollutants may increase mortality associated with coronary heart disease. Moreover, men, people over 60 years old, and diabetics are more susceptible to air pollution, Caixin.com reported.

According to the World Health Organization (WHO), about 4.3 million people die from indoor air pollution and 3.7 million die from outdoor air pollution every year.

Earlier studies in 2006 found that the coronary artery calcium (CAC) has something to do with PM2.5 and traffic-related air pollution. CAC is believed to be an important symbol of coronary atherosclerosis, which is a specific manifestation of Coronary Heart Disease (CHD).

Cardiovascular deaths in rural and urban areas accounted for 45.5 percent and 43.1 percent respectively of the total causes of death, said the report of cardiovascular disease in China in 2018, released by China's National Center of Cardiovascular Diseases.

The report also pointed out that the concentrations of fine particles, sulfur dioxide, nitrogen oxide and total suspended particles were positively correlated with the incidence and death of cardiovascular diseases.