2019 No https://www.researchgate.net/publication/335498668_Characteristics_of_air_pollutants_inside_and_outside_a_primary_school_classroom_in_Beijing_and_respiratory_health_impact_on_children Zhang, Lulu Asia Exposure Study Students Elementary (K-5) Particulate Matter (PM) Particulate matter (PM) Trace gases Water-soluble ions Carbonaceous compounds Lower respiratory infections The results show that air quality inside the classroom was greatly affected by the input of outdoor pollutants; high levels of pollution were observed during both the heating and nonheating periods and indicate that indoor and outdoor air pollution posed a threat to the children's health. Traffic sources near the primary school were the main contributors to indoor and outdoor pollutants during both periods. Moreover, air quality in this primary school was affected by coal combustion and atmospheric reactions during the heating and nonheating periods, respectively. Based on the estimation by exposure-response functions and the weighting of indoor and outdoor pollutants during different periods, the levels of PM2.5, PM 10 and O3 at school had adverse respiratory health effects on children. Longer exposures during the nonheating period contributed to higher health risks.