Spatiotemporal patterns of global air pollution: A multi-scale landscape analysis based on dust and sea-salt removed PM<inf>2.5</inf> data

Abstract

Spatiotemporal patterns of global air pollution are of great significance to environmental management and public health. Studies have revealed the changes in the concentration of dust and sea-salt removed fine particulate matter (PM2.5) pollution (DSRPP). However, the spatial characteristics of DSRPP on multiple scales remain unclear. Therefore, we combined the latest global estimates of the PM2.5 dataset and landscape metrics to investigate the spatiotemporal patterns of DSRPP across global and national scales from 2000 to 2016. We found that the area of DSRPP increased from 1,146,800 km2 to 3,929,800 km2 between 2000 and 2016, a factor of 2.43. The DSRPP became more structurally fragmented and geometrically complex, with the patch density and the landscape shape index of DSRPP increasing by 133.3% and 24.5%, respectively. More than 90% of the DSRPP were concentrated in the middle income countries, especially in India and China. Specifically, the DSRPP in China exhibited a sprawling process before 2007 but a dissipating process after 2007 under the great efforts of the Chinese government in mitigating air pollution, while DSRPP in India remained an aggregation trend. The potential threat to public health posed by the DSRPP increased over time. Populations living in the areas with the DSRPP increased by 141.2% from 2000 to 2016 due to the deterioration of air quality and demographic change. Thus, we suggest that effective actions should be taken to control the main sources of anthropogenic emissions and mitigate the negative effects of DSRPP on public health in the future, especially in the middle income countries such as China and India.