Environmental Justice Assessment of Fine Particles, Ozone, and Mercury over the Pearl River Delta Region, China

Assessment of environmental justice (EJ, a concept related to the distributional fairness of environmental risks) is a crucial component in environmental risk management. However, the risks associated with air pollutants and toxins have rarely been evaluated jointly. Therefore, using an approach integrating modeling, data fusion, and health benefits analysis, we performed an EJ assessment on the mortalities caused by fine particle (PM2.5) and ozone (O-3) concentrations and mercury (Hg) deposition over the Pearl River Delta (PRD) region. The concentration index (CI) was used to measure EJ in low-income distributions and age structures, and a larger value implied a greater EJ issue. The results revealed that the CIs of PM2.5, O-3, and Hg were 0.35, 0.32, and 0.16, respectively, based on the percentage of the low-income population, and 0.39, 0.36, and 0.23, respectively, based on the elderly and children, indicating that environmental injustice was more prominent for PM2.5 and more reflected in the elderly and children. The center (e.g., Guangzhou) and some marginal areas (e.g., northeast of Jiangmen) in the PRD were overburdened areas with PM2.5, O-3, and Hg pollution due to their intensive source emissions. Moreover, cumulative environmental risk (CER) corrected by population vulnerability exhibited significant differences among the cities; for example, cumulative environmental risk scores (CERSs) in Jiangmen, Huizhou, and Zhaoqing were 14.18 to 32.98 times higher than that in Shenzhen. Hence, the implementation of multipollutant control policies for local PM2.5, O-3, and Hg in overburdened areas is recommended to further promote EJ in the PRD.