Assessment of Air Quality in School Environments in Hanoi, Vietnam: A Focus on Mass-Size Distribution and Elemental Composition of Indoor-Outdoor Ultrafine/Fine/Coarse Particles
Trinh Dinh Tran,
Phuong Minh Nguyen,
Dung Trung Nghiem,
Tuyen Huu Le,
Minh Binh Tu,
Laurent Y. Alleman,
Viet Minh Nguyen,
Dong Thanh Pham,
Ngoc Minh Ha,
Minh Nhat Dang,
Chieu Van Le,
Noi Van Nguyen
Affiliations
Trinh Dinh Tran
VNU–Key laboratory of Advanced Materials for Green Growth, Faculty of Chemistry, University of Science, Vietnam National University, Hanoi, N0.19, Le Thanh Tong street, Hanoi 110000, Vietnam
Phuong Minh Nguyen
Faculty of Chemistry, University of Science, Vietnam National University, Hanoi, N0.19, Le Thanh Tong street, Hanoi 110000, Vietnam
Dung Trung Nghiem
School of Environmental Science and Technology, Hanoi University of Science and Technology, N0.1 Dai Co Viet road, Hanoi 112400, Vietnam
Tuyen Huu Le
VNU–Key laboratory of Advanced Materials for Green Growth, Faculty of Chemistry, University of Science, Vietnam National University, Hanoi, N0.19, Le Thanh Tong street, Hanoi 110000, Vietnam
Minh Binh Tu
Faculty of Chemistry, University of Science, Vietnam National University, Hanoi, N0.19, Le Thanh Tong street, Hanoi 110000, Vietnam
Laurent Y. Alleman
Department of Atmospheric Science and Environmental Engineering, SAGE, IMT Lille–Douai, University of Lille, 59000 Lille, France
Viet Minh Nguyen
VNU–Key laboratory of Advanced Materials for Green Growth, Faculty of Chemistry, University of Science, Vietnam National University, Hanoi, N0.19, Le Thanh Tong street, Hanoi 110000, Vietnam
Dong Thanh Pham
VNU–Key laboratory of Advanced Materials for Green Growth, Faculty of Chemistry, University of Science, Vietnam National University, Hanoi, N0.19, Le Thanh Tong street, Hanoi 110000, Vietnam
Ngoc Minh Ha
VNU–Key laboratory of Advanced Materials for Green Growth, Faculty of Chemistry, University of Science, Vietnam National University, Hanoi, N0.19, Le Thanh Tong street, Hanoi 110000, Vietnam
Minh Nhat Dang
VNU–Key laboratory of Advanced Materials for Green Growth, Faculty of Chemistry, University of Science, Vietnam National University, Hanoi, N0.19, Le Thanh Tong street, Hanoi 110000, Vietnam
Chieu Van Le
Faculty of Environmental Sciences, University of Science, Vietnam National University, Hanoi, N0.334, Nguyen Trai Street, Hanoi 120000, Vietnam
Noi Van Nguyen
VNU–Key laboratory of Advanced Materials for Green Growth, Faculty of Chemistry, University of Science, Vietnam National University, Hanoi, N0.19, Le Thanh Tong street, Hanoi 110000, Vietnam
Indoor and outdoor ultrafine, accumulation mode, and coarse fractions collected at two preschools (S1 and S2) in Hanoi capital, Vietnam were characterized in terms of mass-size distribution and elemental composition to identify major emission sources. The sampling campaigns were performed simultaneously indoors and outdoors over four consecutive weeks at each school. Indoor average concentrations of CO2 and CO at both schools were below the limit values recommended by American Society of Heating, Refrigerating and Air-Conditioning Engineers (1000 ppm for CO2) and World Health Organization (7 mg/m3 for CO). Indoor concentrations of PM2.5 and PM10 at S1 and S2 were strongly influenced by the presence of children and their activities indoors. The indoor average concentrations of PM2.5 and PM10 were 49.4 µg/m3 and 59.7 µg/m3 at S1, while those values at S2 were 7.9 and 10.8 µg/m3, respectively. Mass-size distribution of indoor and outdoor particles presented similar patterns, in which ultrafine particles accounted for around 15–20% wt/wt while fine particles (PM2.5) made up almost 80% wt/wt of PM10. PM2.5–10 did not display regular shapes while smaller factions tended to aggregate to form clusters with fine structures. Oxygen (O) was the most abundant element in all fractions, followed by carbon (C) for indoor and outdoor particles. O accounted for 36.2% (PM0.5–1) to 42.4% wt/wt (PM0.1) of indoor particles, while those figures for C were in the range of 14.5% (for PM0.1) to 18.1% (for PM1–2.5). Apart from O and C, mass proportion of other major and minor elements (Al, Ca, Cr, Fe , K, Mg, Si, Ti) could make up to 50%, whereas trace elements (As, Bi, Cd, Co, Cr, Cu, La, Mn, Mo, Ni, Pb, Rb, Sb, Se, Sn, Sr, and Zn) accounted for less than 0.5% of indoor and outdoor airborne particles. There were no significant indoor emission sources of trace and minor elements. Traffic significantly contributed to major and trace elements at S1 and S2.
