
Keywords: هیدروکربن آروماتیک چندحلقهای; PM; particulate matter; PM2.5; particulate matter with an aerodynamic diameterâ¯<â¯2.5â¯Î¼m; HMCHH; Beijing Haidian Maternal and Child Health Hospital; SD; standard deviation; PKUERS; Peking University Urban Atmosphere Environment Monitoring Station; A