Short-term and lagged effects of ambient air pollution on emergency visits for cardiovascular diseases modified by meteorological factors

Environmental factors are associated with emergency cardiovascular disease (CVD) visits; however, their effects remain incompletely understood. Herein, we examined the relationships between short-term air pollution exposure and emergency CVD visits, and the potential effects of minimum temperature (Temp-Min) and mean relative humidity (RH). Data on emergency CVD visits were collected from Beijing Tiantan Hospital between 2014 and 2018. Average concentrations of air pollutants during the same period, including particulate matter ≤2.5 μm and ≤10 μm in diameter (PM 2.5 and PM 10 , respectively), nitrogen dioxide (NO 2 ), sulfur dioxide (SO 2 ), and meteorological variables were collected to estimate exposure levels. A time-series quasi-Poisson regression analysis was conducted among 25,896 patients over 1461 days to examine the effects of air pollutants on emergency CVD outpatients. A 10 μg/m 3 increase in PM 2.5 , NO 2 , and SO 2 was associated with significant increases in emergency CVD visits of 0.42% (95% confidence interval [CI]: 0.16%, 0.68%), 1.31% (95% CI: 0.60%, 2.03%), and 2.54% (95% CI: 0.91%, 4.19%), respectively. Stronger associations were observed in males and in the oldest age group (61–80 years). The effects of air pollution on emergency CVD visits tended to be more pronounced under conditions of lower temperature and higher RH. These findings suggest that the short-term and lagged effects of air pollution on emergency CVD visits show stronger associations modified by low temperature and high RH.