Air particulate matter and cardiovascular disease: a narrative review

Consistent evidences from both epidemiological and experimental studies have demonstrated that short- and long-term exposure to particulate matter (PM), in particular to the finest particles (i.e. airborne PM with aerodynamic diameter less than 2.5 μm, PM2.5), is associated with cardiovascular morbidity and mortality. PM concentration has been linked with several clinical manifestations of cardiovascular diseases (CVD), including myocardial infarction, stroke, heart failure, arrhythmias, and venous thromboembolism. Noteworthy, some groups of subjects, like elderly, diabetics, or those with known coronary artery disease, appear specifically susceptible to the harmful effects triggered by PM exposure. Although the PM-related risk for a single individual appears relatively low, the PM-related population attributable risk is impressive. Recent studies indicate that the PM-CVD relationship is likely more complex than a mere quantitative association between overall PM concentration and disease risk. Indeed, the biological effects of PM may vary in function of both the aerodynamic diameter and the chemical composition. Moreover, it has been shown that the influence of air pollution on health is not limited to PM. Indeed, other gaseous pollutants may play an independent role in CVD, suggesting the need to develop multi-pollutant preventive approaches. Causality has been recently strongly supported by observations showing reduced CVD mortality after coordinated community policies resulting in lowering PM exposure at population level. An in-depth knowledge on the heterogeneous sources, chemical compounds, and biological effects of PM may help to propose more accurate and clinically effective recommendations for this important and modifiable factor contributing to CVD burden.