Wang R, Yang B, Liu P, et al. - Researchers sought to determine how air pollution especially PM_2.5 (particulate matter with a diameter of below 2.5 μm) influence health-related behaviors such as physical activities and social contact, in order to ascertain their role as mediators of depression among older adults in China. From the CHARLS (China Health and Retirement Longitudinal Study) of 2011-2015, data (N = 24,623) were obtained for this work. Depression was measured using CES-D 10 (Center for Epidemiology Studies of Depression scale). Findings suggest that older Chinese adults exhibit an increase in depressive symptoms in correlation to exposure to the particulate matter as the exposure results in a decrease in their physical activities and social contact. Also, increasing PM_2.5 concentrations reduced the positive effects of physical activities and social contact on depression.