The associations of various constituents of fine particulate matter and ozone air pollution with cardiorespiratory outcomes
PM2.5 is the sixth health risk factor globally and is responsible for 4.58 million premature deaths and 142.52 million Disability-Adjusted Life Years (DALYs) in 2017. Although many studies have reported increased morbidity and mortality associated with PM2.5, very few large cohort studies have investigated the associations between long-term exposure to PM2.5 and sub-clinical indicators and effect biomarkers. Moreover, PM2.5 is a complex mixture containing various chemical constituents. The key constituents of PM2.5 mixture that are mainly responsible for the adverse cardiorespiratory effects are less understood and largely inconsistent. As one of the major oxidative irritants among air pollutants, ozone has been demonstrated to increase the risk of respiratory diseases. However, there was broad inconsistency in the relationship between ozone and cardiovascular outcomes. Large cohort studies are warranted to evaluate the causality of ozone and cardiovascular diseases.
The UK Biobank data provides a unique opportunity to investigate the long-term cardiorespiratory effects of PM2.5 constituents and ozone. In this proposed study, we will further identify the most toxic constituents for various cardiorespiratory outcomes and to evaluate the causality in the cardiovascular effects of long-term ozone exposure.
The three-year project will identify the key constituents of PM2.5 that play major roles in inducing pathophysiological effects, which will provide the biological plausibility that is critically important for causal inferences. PM2.5 constituents, acting as indicators of pollution sources, may provide new insights into targeted regulation and control of PM2.5 air pollution in the United Kingdom. This proposal would also shed some light on the causality in the effects of long-term exposure to ozone on cardiorespiratory outcomes, which is helpful in health risk assessment and disease burden estimation of ozone.