The authors of this study examined the associations of hourly peak concentration of PM2.5 with cardiovascular mortality in Guangzhou, China. They obtained daily data on cardiovascular mortality and hourly PM2.5 concentrations from January 19, 2013, through June 30, 2015, and applied generalized additive models to evaluate the associations with adjustment for potential confounding factors. They found significant associations between hourly peak concentration of PM2.5 and increased cardiovascular mortality, particularly from ischemic heart diseases and cerebrovascular diseases. The effects remained after adjustment for daily mean PM2.5 and gaseous air pollutants, though there was a high correlation between PM2.5 peak and PM2.5 mean (correlation coefficient=0.95). No significant association was observed for acute myocardial infarction. They conclude that, in addition to daily mean concentration of PM2.5, hourly peak concentration of PM2.5 might be one important risk factor of cardiovascular mortality and should be considered an important air pollution indicator when assessing the possible cardiovascular effects of PM2.5.
Lin, H., Liu, T., Xiao, J., Zeng, W., Guo, L., Li, X., . . . Ma, W. (2016). Hourly peak PM2.5 concentration associated with increased cardiovascular mortality in Guangzhou, China. Journal of Exposure Science and Environmental Epidemiology. Advance online publication. doi:10.1038/jes.2016.63