Exposure to air pollutants of fine particulate matter (PM2.5) is a major threat to human health. Research on PM2.5 exposure has been on the rise in recent years, but there has been a lack of systematic reviews and meta-analyses to synthesize the existing knowledge. This study aims to provide a comprehensive review of the current state of PM2.5 exposure research, highlighting the key findings, methodological limitations, and future research directions. The review will cover the major sources of PM2.5 exposure, the health effects of PM2.5 exposure, and the current research gaps in this field. By providing a thorough understanding of the current state of PM2.5 exposure research, this study aims to inform policy makers, researchers, and the general public about the importance of addressing PM2.5 exposure and the need for further research in this area.