In addition to harmful gases such as carbon monoxide, air pollution contains tiny particles that have been linked to health problems, including cardiovascular disease and asthma. Most studies have analyzed the potential health effects of larger-sized particulate matter (PM), such as particles less than 2.5 μm in diameter (PM2.5). Now, researchers in China report in an open-access paper in Environmental Science & Technology Letters that particles with diameters less than 1 μm (PM1) are even more strongly correlated with cardiovascular disease.
Air pollution is associated with many hazardous effects, including cardiovascular disease (CVD), respiratory disease (RD), and other diseases. Different size-fractioned particulate matters (PMs) have been reported to have a variety of physicochemical properties, toxicities, and shapes. Although a large number of epidemiological studies have addressed the associations between health outcomes and PM with an aerodynamic diameter of <10 μm (PM10) or ambient fine particulate matter (PM2.5, PM with an aerodynamic diameter of <2.5 μm), PM1 (PM with an aerodynamic diameter of <1 μm) may have much more deleterious health effects due to its higher surface area:volume ratio.—Yin et al.
Pooled associations between size-fractioned PM and cause-specific mortality in 65 cities in China. The associations are expressed as the percentage difference (95% confidence interval) in daily mortality per 10 μg/m3 increase in two-day moving average PM1. Abbreviations: PM, particulate matter; CVD, cardiovascular disease; CHD, coronary heart disease; RD, respiratory disease; COPD, chronic obstructive pulmonary disease. Credit: ACS, Yin et al.
To better understand air pollution, a nationwide PM1 monitoring campaign was recently performed in China.
Zhaomin Dong, Maigeng Zhou and colleagues analyzed the data from 65 Chinese cities, to determine if PM1 exposure correlated with the number of non-accidental deaths in each city during the same time period.
They found that for every 10 μg/m3 increase in PM1, there was a 0.29% increased risk of cardiovascular disease—21% higher than the risk related to PM2.5 (0.24%).
The finer PM1 could more easily deposit in the lungs and circulation than larger particles, which might explain the increased health risks, the researchers say.
The authors acknowledge funding from the Ministry of Science and Technology of the People’s Republic of China, the National Natural Science Foundation of China and the Fundamental Research Project of Beihang University.
Peng Yin, Jianping Guo, Lijun Wang, Wenhong Fan, Feng Lu, Moning Guo, Silvia B. R. Moreno, Ying Wang, Hao Wang, Maigeng Zhou, and Zhaomin Dong (2020) “Higher Risk of Cardiovascular Disease Associated with Smaller Size-Fractioned Particulate Matter” Environmental Science & Technology Letters doi: 10.1021/acs.estlett.9b00735