Urban-rural disparity of the short-term association of PM2.5 with mortality and its attributable burden

Abstract

Although studies have investigated the associations between PM_2.5 and mortality risk, evidence from rural areas is scarce. We aimed to compare the PM_2.5-mortality associations between urban cities and rural areas in China. Daily mortality and air pollution data were collected from 215 locations during 2014-2017 in China. A two-stage approach was employed to estimate the location-specific and combined cumulative associations between short-term exposure to PM_2.5 (lag 0-3 days) and mortality risks. The excess risks (ER) of all-cause, respiratory disease (RESP), cardiovascular disease (CVD), and cerebrovascular disease (CED) mortality for each 10 μg/m³ increment in PM_2.5 across all locations were 0.54% (95% confidence interval [CI]: 0.38%, 0.70%), 0.51% (0.10%, 0.93%), 0.74% (0.50%, 0.97%), and 0.52% (0.20%, 0.83%), respectively. Slightly stronger associations for CVD (0.80% versus 0.60%) and CED (0.61% versus 0.26%) mortality were observed in urban cities than in rural areas, and slightly greater associations for RESP mortality (0.51% versus 0.43%) were found in rural areas than in urban cities. A mean of 2.11% (attributable fraction [AF], 95% CI: 1.48%, 2.76%) of all-cause mortality was attributable to PM_2.5 exposure in China, with a larger AF in urban cities (2.89% [2.12%, 3.67%]) than in rural areas (0.61% [-0.60%, 1.84%]). Disparities in PM_2.5-mortality associations between urban cities and rural areas were also found in some subgroups classified by sex and age. This study provided robust evidence on the associations of PM_2.5 with mortality risks in China and demonstrated urban-rural disparities of PM_2.5-mortality associations for various causes of death.

Keywords: China; fine particulate matter; mortality; urban-rural disparity.

Graphical abstract

Figure 2

The cumulative exposure-response curves between PM_2.5 and mortality over lag 0–3 days in all urban and rural locations Note: The solid lines represent the cumulative relative risk of mortality over 4 days (lag 0–3 days) for PM_2.5 concentrations, which are the combined effects of exposure and lag dimensions.

Figure 1

The distribution of 215 Chinese locations and their mean daily PM_2.5 concentration during 2014–2017 (A) Guangdong; (B) Zhejiang; (C) Jilin; (D) Yunnan.