CHARACTERIZATION OF SIZE-RESOLVED PARTICLES AND CHEMICAL COMPOSITION AT TWO ELEMENTARY SCHOOLS IN HANOI, VIETNAM

Indoor and outdoor ultrafine, accumulation mode, and coarse fractions collected at two elementaryschools (S1 and S2) in Hanoi capital, Vietnam were characterized in terms of mass, numberconcentrations, particle morphology, and chemical composition to assess the indoor air quality atthe examined schools. The sampling campaigns were performed simultaneously indoors andoutdoors for three consecutive weeks at each school. Indoor average concentrations of CO2 and COat both schools were below the limit values recommended by the American Society of Heating,Refrigerating and Air-Conditioning Engineers (1000 ppm for CO2) and World Health Organization(7 mg/m3 for CO). Indoor mass concentrations of PM10 and CO2 at S1 and S2 were stronglyinfluenced by the presence of children and their activities indoors whereas the numberconcentration of particlesseemed not to be impacted by occupants’ activities. Water-soluble ionscommonly presented unimodal distribution for indoor and outdoor airborne particles at S1 and S2,which accounted for typically a proportion of around 3.5-5% of the total mass of particles. Oxygen(O) was the most abundant element in all fractions, followed by carbon (C) for indoor and outdoorparticles.