PFAS in PMs might be the escalating hazard to the lung health

Atmospheric particulate matter (PM) is a dominant source of air pollution, in particular, molecules less than 2.5 μm in diameter, endangering human health. An estimated 2.1 million deaths from exposure to PM_2.5 and 700,000 cases of respiratory disease caused by atmospheric pollution were reported on an annual basis. The main components of PM_2.5 include heavy metal elements, water-soluble ions, carbon aerosols, ozone, and organic compounds. Per- and polyfluoroalkyl substances (PFASs) are a large group of representative pollutants among the organic compounds absorbed in PM_2.5. PFASs are widely used in industrial production and hardly degraded in the environment, resulting in their accumulation in water, food, and air, and abosorbed by humans via ingestion and inhalation. On the other hand, accumulation of PFAS in the human body is proving to be associated with some unfavorable health outcomes, whereas the mechanisms underlying the effects of PFAS exposure on human lung diseases remain unclear at present. The toxicological effects of organic components are a significant focus of research. This review will fix our attention on the changes in the distribution, composition, and content of PFAS in PM_2.5 by location and year, and provide an overview on the influence of PM_2.5 and PFAS on lung health, with indications of possible synergistic adverse effects of PM_2.5 and PFAS on pulmonary homeostasis.