Predicted Future Mortality Attributed to Increases in Temperature and PM10 Concentration under Representative Concentration Pathway Scenarios

Abstract

As climate change progresses, understanding the impact on human health associated with the temperature and air pollutants has been paramount. However, the predicted effect on temperature associated with particulate matter (PM₁₀) is not well understood due to the difficulty in predicting the local and regional PM₁₀. We compared temperature-attributable mortality for the baseline (2003-2012), 2030s (2026-2035), 2050s (2046-2055), and 2080s (2076-2085) based on a distributed lag non-linear model by simultaneously considering assumed levels of PM₁₀ on historical and projected temperatures under representative concentration pathway (RCP) scenarios. The considered projected PM₁₀ concentrations of 35, 50, 65, 80, and 95 μg/m³ were based on historical concentration quantiles. Our findings confirmed greater temperature-attributable risks at PM₁₀ concentrations above 65 μg/m³ due to the modification effect of the pollutants on temperature. In addition, this association between temperature and PM₁₀ was higher under RCP8.5 than RCP4.5. We also confirmed regional heterogeneity in temperature-attributable deaths by considering PM₁₀ concentrations in South Korea with higher risks in heavily populated areas. These results demonstrated that the modification association of air pollutants on health burdens attributable to increasing temperatures should be considered by researchers and policy makers.

Keywords: high-temperature; inhalable particulate matter; modification effect; regional variation.

Figure 1

Mean PM₁₀ concentration distribution (grey dot) with outlier (blue dot) and its trend (red line) during the baseline period (2003–2012) (left), and the quartile concentration of the baseline period without outliers, which ranged from Q1 − 1.5 × IQR to Q3 + 1.5 × IQR (right).

Figure 2

Estimated temperature-mortality curves with various PM₁₀ concentrations (0, 35, 50, 65, 80, and 95 μg/m³) in South Korea (left) with 95% confidence interval (gray shaded region), and enlarged high-temperature region (right).

Figure 3

Relative risk boxplots of the 229 districts for the baseline and projection periods (2030s (2026–2035), 2050s (2046–2055), and 2080s (2076–2085)) under predicted temperature scenarios (RCP4.5 and 8.5) and the medium-variant population scenario. Red, yellow, green, light blue, navy, and pink colors correspond to PM₁₀ levels of 0, 35, 50, 65, 80, and 95 μg/m³, respectively.

Figure 4

National distribution of temperature-attributable deaths considering simultaneous effects of PM₁₀ and temperature when PM₁₀ was assumed to be 35 μg/m³, for (a) and (c), and 95 μg/m³, for (b) and (d), under RCP8.5 in the 2030s and 2080s.