Spatiotemporal dynamics of PM2.5 pollution and associated exposure risks for populations in Shandong Province based on remote sensing data (2000–2020)

Long-term exposure to higher concentrations of PM_2.5 pollution may cause harm to the physical and mental health of humans. Clarifying the spatiotemporal characteristics of PM_2.5 concentration and its population exposure risk (PER) can provide scientific reference for improving the regional habitat environment and reducing air pollution damage to human health. Here, this paper adopted the Sen's nonparametric method, Mann-Kendall test, Hurst exponent, and population exposure risk model to analyse the spatial and temporal variations of PM_2.5 pollution and its exposure risk in Shandong Province (SDP) based on PM_2.5 concentration and population data during 2000-2020. The results showed that: (1) Spatial distribution of PM_2.5 concentration in SDP showed “high in the west and low in the east”, with an interannual fluctuation trend of “significant increase - fluctuating decrease - significant decrease” during 2000-2020. The area with a downward trend of PM_2.5 concentration accounted for 59.419% of the whole province, and the area where air quality will be further improved in the future accounted for about two-thirds. (2) The annual mean value of PER to PM_2.5 pollution in SDP was fragmented in spatial distribution, with low risk dominating in most areas, while the risk areas were mainly distributed in densely populated urban areas. The area with a downward, unchanged, and upward trend of PER to PM_2.5 pollution accounted for 61.827%, 0.423%, and 37.750% of the whole province, respectively. In addition, PER to PM_2.5 pollution will be further reduced in 55.633% of SDP in the future.