Projections of mortality risk attributable to short-term exposure to landscape fire smoke in China, 2021–2100: a health impact assessment study

Abstract

Landscape fire smoke, including smoke from all vegetation burning in natural and cultural landscapes, remains a threat to the health of the population. However, the future health impacts of landscape fire smoke in China have not been sufficiently investigated. We aimed to estimate the mortality risk attributable to landscape fire-related PM2·5 under different scenarios. In this health impact assessment study, we used the projected population and landscape fire-related PM2·5 concentration to calculate deaths attributable to short-term exposure to landscape fire smoke PM2·5 during 2021-2100. We did the analysis in three defined future periods: 2021-40 (near term), 2051-70 (medium term), and 2081-2100 (long term), with 1986-2005 as the historical period. We used fire-specific short-term epidemiological functions with the regional parameters specific to China. We assessed the mortality risks of landscape fire-related smoke and further identified their spatiotemporal distribution under two shared socioeconomic pathway (SSP) scenarios: SSP1-2·6, an optimistic scenario with strict control of carbon emissions, and SSP2-4·5, an intermediate scenario with weaker control of carbon emissions. The national mortality rate attributable to short-term exposure (ie, a few days) to landscape fire-related PM2·5 is projected to increase compared with historical values. The national deaths attributable to landscape fire smoke PM2·5 could peak in 2021-40, with increases of 28·10% (95% CI 14·08-53·11) under the SSP1-2·6 scenario and 37·38% (14·08-53·11) under the SSP2-4·5 scenario. Deaths would then decrease slightly during 2051-70 and 2081-2100. The provinces with the highest projected number of deaths attributable to landscape fire-related PM2·5 are located in east and south-central China, and those with the largest percentage increase in projected deaths are located in northwest and southwest China. Our results suggest that global warming could increase the contribution of landscape fire smoke to the total PM2·5 concentration, leading to an increase in the mortality rate in China. Our findings could help policy makers implement effective interventions in hotspot areas during different periods to reduce the impact of landscape fire smoke on human health. The National Natural Science Foundation of China, National Key Research and Development Program of China, and the Wellcome Trust.