Short-term cumulative lag impacts of PM₁₀ exposure on mortality at various air temperature among residents aged 65 years and over in Chengdu city

  Objective   To explore the difference in cumulative lag impacts of particulate matter less than 10 μm in aerodynamic diameter (PM₁₀) exposure on daily mortality in relation to various air temperature among residents aged 65 years and over in Chengdu city.

  Methods   The scales of air temperature were defined by interquartile range (IQR) of annual mean temperature during 2013 – 2016. We estimated cumulative lag impacts of PM₁₀ on mortality and the duration of the cumulative lag impacts with distributed lag nonlinear quasipoisson regression model by temperature scale stratum.

  Results   After controlling for daily mean temperature, a significant cumulative lag impact of PM₁₀ (excess mortality risk ER = 0.2 %, 95 % confidence interval 95 % CI: 0.0 % – 0.3 %) for a 10 μg/m³ increase on non-accidental mortality was observed. The lag impacts were postponed two to five days and the lag impacts lasted for three to five days. Stratified by IQR of temperature, the associations between PM₁₀ and cumulative lag impacts of PM₁₀ on the mortality were quite different in different temperature ranges. The impacts were significant at high and medium temperature ranges. However, significant impacts were not observed at low temperature range. As for high temperature range, significant cumulative lag impacts of PM₁₀ (for a 10 μg/m³ increase) on non-accidental mortality (ER = 3.5 %, 95 % CI: 0.1 % – 7.0 %) and cardiovascular mortality (ER = 3.3 %, 95 % CI: 0.2 % – 6.4 %) were observed. As for medium temperature range, significant cumulative lag impacts of PM₁₀ (for a 10 μg/m³ increase) on non-accidental mortality (ER = 0.3 %, 95 % CI: 0.1 % – 0.5 %), cardiovascular mortality (ER = 0.3%, 95 % CI: 0.1 % – 0.6 %), and cancer mortality (ER = 0.5%, 95 % CI: 0.2 % – 0.9%) were observed. No significant cumulative lag impacts of PM₁₀ (for a 10 μg/m³ increase) on respiratory mortality were observed on whole temperature range.

  Conclusion   Cumulative lag impacts of PM₁₀ on mortality of residents aged 65 years and over in Chengdu city are influenced significantly by ambient air temperature.