PM_2.5 Concentration Exposure over the Belt and Road Region from 2000 to 2020

Ambient fine particulate matter (PM_2.5) can cause respiratory and heart diseases, which have a great negative impact on human health. While, as a fast-developing region, the Belt and Road (B&R) has suffered serious air pollution, more detailed information has not been revealed. This study aims to investigate the evolutionary relationships between PM_2.5 air pollution and its population-weighted exposure level (PWEL) over the B&R based on satellite-derived PM_2.5 concentration and to identify the key regions for exposure control in the future. For this, the study focused on the B&R region, covering 51 countries, ranging from developed to least developed levels, extensively evaluated the different development levels of PM_2.5 concentrations during 2000-2020 by spatial-temporal trend analysis and bivariate spatial correlation, then identified the key regions with high risk under different levels of Air Quality Guidelines (AQG). Results show that the overall PM_2.5 and PWEL of PM_2.5 concentration remained stable. Developing countries presented with the heaviest PM_2.5 pollution and highest value of PWEL of PM_2.5 concentration, while least developed countries presented with the fastest increase of both PM_2.5 and PWEL of PM_2.5 concentration. Areas with a high level and rapid increase PWEL of PM_2.5 concentration were mainly located in the developing countries of India, Bangladesh, Nepal, and Pakistan, the developed country of Saudi Arabia, and least developed countries of Yemen and Myanmar. The key regions at high risk were mainly on the Indian Peninsula, Arabian Peninsula, coastal area of the Persian Gulf, northwestern China, and North China Plain. The findings of this research would be beneficial to identify the spatial distributions of PM_2.5 concentration exposure and offer suggestions for formulating policies for the prevention and control PM_2.5 air pollution at regional scale by the governments.