Overview of PM2.5 and health outcomes: Focusing on components, sources, and pollutant mixture co-exposure

PM2.5 varies in source and composition over time and space as a complicated mixture. Consequently, the health effects caused by PM2.5 varies significantly over time and generally exhibit significant regional variations. According to numerous studies, a notable relationship exists between PM2.5 and the occurrence of many diseases, such as respiratory, cardiovascular, and nervous system diseases, as well as cancer. Therefore, a comprehensive understanding of the effect of PM2.5 on human health is critical. The toxic effects of various PM2.5 components, as well as the overall toxicity of PM2.5 are discussed in this review to provide a foundation for precise PM2.5 emission control. Furthermore, this review summarizes the synergistic effect of PM2.5 and other pollutants, which can be used to draft effective policies.