In addition, HMW HA alleviates fine particulate matter (PM2.5)-induced ALI by suppressing reactive oxygen species (ROS) in the apoptosis signal-regulating kinase 1 (ASK1)-p38/c-Jun N-terminal kinase (JNK) pathway to reduce pulmonary epithelial apoptosis and inhibiting macrophage M1 polarization to limit the secretion of pro-inflammatory cytokines [21,22]. This evidence concerns the gene MAPK14 and acute respiratory distress syndrome.