Concentration and health risk assessment of heavy metals in airborne particles at nusery schools in Ha Noi

Abstract

Indoor air quality is increasingly important as people spend more and more time for indoor activities. A sampling campaign was conducted to sample airborne particles at nursery schools in Hanoi in May and June 2018. The sampling strategy was performed during lessons and in absence of children in classrooms. Heavy metals and trace elements (Cu, Pb, Cd, Zn, Ni, As, Mn, Cr, Hg, Fe…) were quantified by using ICP-MS method. Emission sources of heavy metals were estimated using statistical analyses such as factor analysis while cancer risk assessment was conducted using chronic daily intake (CDI) and slop factor (SF). In the presence of children, indoor concentrations of heavy metals and trace elements were within the range from 1,7-3,2 ng/m3 (Cd) to 1588-3238 ng/m3 (Zn), while these corresponding values obtained when the rooms were empty were in the ranges of 0,6-0,9 and 746,2-2011 ng/m3. Indoor/outdoor ratios of studied elements varied from school to school and ranged from 0.25 to 2.88, implying presence of indoor emission sources. The calculated cancer risks ranged from 4.8x10-6 to 5.0x10-4, being hihgher than limit values set by USEPA, implying significant health risk to young children.