Seasonal effects of PM10 concentrations on mortality in Tianjin, China: a time-series analysis

Abstract

Aim There are uncertainties regarding the modification effects of season and temperature on the relationship between air pollution and mortality. This study aims to examine the effects of season and temperature on mortality associated with particulate matter less than 10 μm in diameter (PM 10 ) in Tianjin, China. Methods Time-series analysis was used to explore the modification effects of season and temperature on the association between PM 10 and cause-specific mortality in Tianjin between 2006 and 2009. The causes studied were overall nonaccidental mortality and subcategories of cardiovascular, respiratory, cardiopulmonary, stroke, and ischemic heart diseases (IHD). Results The association between PM 10 and mortality showed a strong seasonal pattern and the effects of PM 10 on causespecific mortalities were strongest for high temperature days. Generally, the adverse effects were stronger in summer than for other seasons, except for respiratory mortality. In the summer period, a 10 μg/m 3 increase in PM 10 at 0-1 days was associated with an increase in mortality for nonaccidental (0.95 %, 95 % confidence interval [CI]: 0.45, 1.45), cardiovascular (1.40 %, 95 %CI: 0.77, 2.03), cardiopulmonary (1.37 %, 95 %CI: 0.77, 1.98), IHD (1.55 %, 95 %CI: 0.73, 2.37), and stroke (1.27 %, 95 % CI: 0.37, 2.12) causes. The overall increase in mortality per 10 μg/m 3 increase in PM 10 was 0.42 % (95 %CI: 0.26, 0.58) for nonaccidental, 0.41 % (95 %CI: 0.21, 0.62) for cardiovascular, 0.46 % (95 %CI: 0.26,0.65) for cardiopulmonary, 0.57 % (95 %CI: 0.30, 0.84) for IHD, and 0.32 % (95 %CI: 0.03,0.61) for stroke. At high temperatures (≥23.8°C), a 10 μg/m 3 increase in PM 10 at 0-1 days was associated with an increase in mortality of 0.90 % (95 %CI: 0.61,1.19) for non-accidental, 1.01 % for cardiovascular, 1.40 % (95 %CI: 0.55, 2.27) for respiratory, 1.06 % (95 %CI: 0.71, 1.41) for cardiopulmonary, 1.47 % (95 %CI: 1.00, 1.94) for IHD, and 0.75 % (95 %CI: 0.24, 1.28) for stroke. In addition, the PM 10 effects of high temperature days were stronger for those aged 65 years and over. Conclusion Season and temperature could modify the adverse effects of PM 10 . An increase in hot summer days caused by climate change may enhance the risks of air pollution on human health. More attention should be paid to older populations, especially in summer and days with high temperatures.

PM<sub>10</sub> Exposure and Non-accidental Mortality in Asian Populations: A Meta-analysis of Time-series and Case-crossover Studies

“…In the case of selecting studies from overlapping datasets, periods or regions, studies with results from more recent and longer periods were selected. In total, eight time-series studies [14-21] and four case-crossover studies [22-25] were finally selected for the meta-analysis (Figure 1). …”

Seasonal variation of particle-induced oxidative potential of airborne particulate matter in Beijing

“…Many previous studies have discussed the effect of the seasonal variation on particle pollutionrelated mortality and morbidity and suggested that higher temperature would significantly enhance the health effects of PM exposure and result in a stronger PM effect on daily mortality (Katsouyanni et al, 1993(Katsouyanni et al, , 2001Ren et al, 2006;Qian et al, 2008). It has been noticed in Beijing (Li et al, 2013b) and Tianjin (Li et al, 2011(Li et al, , 2013a) that adverse effects were strongest in summer compared to the other seasons. The positive association between the higher particle-induced oxidative potential of PM and the higher air temperature may explain why temperature would enhance the PM health effect.…”

Fusing Observational, Satellite Remote Sensing and Air Quality Model Simulated Data to Estimate Spatiotemporal Variations of PM2.5 Exposure in China

“…Severe PM 2.5 pollution in China has attracted considerable public attention [10][11][12] and inspired numerous epidemiological studies to investigate the health effects of air pollution in China since 2013 [13][14][15][16][17][18]. Accurately assessing PM 2.5 exposure is critical for estimating its health risks in such epidemiological studies.…”

“…Accurately assessing PM 2.5 exposure is critical for estimating its health risks in such epidemiological studies. However, due to the limited number of ground monitors in China, previous studies generally ignored the spatial variation of PM 2.5 and assessed the ambient exposure uniformly using one monitor or averages of several monitors located within a city or a municipality [13][14][15][16], which causes exposure misclassification. Therefore, accurately estimating the fine-scale spatiotemporal variation of ground PM 2.5 may lay a foundation for future health-related studies of PM 2.5 in China.…”