Environmental determinants of cardiovascular disease: lessons learned from air pollution

Air pollution is well recognized as a major risk factor for chronic non-communicable diseases and has been estimated to contribute more to global morbidity and mortality than all other known environmental risk factors combined. Although air pollution contains a heterogeneous mixture of gases, the most robust evidence for detrimental effects on health is for fine particulate matter (particles ≤2.5 µm in diameter (PM 2.5 )) and ozone gas and, therefore, these species have been the main focus of environmental health research and regulatory standards. The evidence to date supports a strong link between the risk of cardiovascular events and all-cause mortality with PM 2.5 across a range of exposure levels, including to levels below current regulatory standards, with no ‘safe’ lower exposure levels at the population level. In this comprehensive Review, the empirical evidence supporting the effects of air pollution on cardiovascular health are examined, potential mechanisms that lead to increased cardiovascular risk are described, and measures to reduce this risk and identify key gaps in our knowledge that could help address the increasing cardiovascular morbidity and mortality associated with air pollution are discussed. A strong relationship exists between exposure to air pollution and cardiovascular events. In this Review, Rajagopalan and colleagues summarize the evidence supporting the detrimental effects of air pollution on cardiovascular health and describe the potential mechanisms involved in air pollution-mediated cardiovascular mortality. Key points Air pollution is the most important environmental cardiovascular risk factor, with fine particulate matter (PM 2.5 ) and ozone gas being the most-studied air pollutants. The health effects of air pollution might depend on chronic exposure, pre-existing medical conditions and sources or composition of the pollutants. Multiple primary initiating and secondary effector mechanisms are responsible for the cardiovascular effects of air pollution. Numerous animal and human studies have shown that inhalation of PM 2.5 pollution can contribute to cardiovascular disease and mortality. The most widely studied personalized approaches to reducing the cardiovascular risk of air pollution include the use of face masks and in-home air purifiers.