Personal exposure measurements of school-children to fine particulate matter (PM2.5) in winter of 2013, Shanghai, China.

Objective: The aim of this study was to perform an exposure assessment of PM_2.5 (particulate matter less than 2.5μm in aerodynamic diameter) among children and to explore the potential sources of exposure from both indoor and outdoor environments. Methods: In terms of real-time exposure measurements of PM_2.5, we collected data from 57 children aged 8–12 years (9.64 ± 0.93 years) in two schools in Shanghai, China. Simultaneously, questionnaire surveys and time-activity diaries were used to estimate the environment at home and daily time-activity patterns in order to estimate the exposure dose of PM_2.5 in these children_. Principle component regression analysis was used to explore the influence of potential sources of PM_2.5 exposure. Results: All the median personal exposure and microenvironment PM_2.5 concentrations greatly exceeded the daily 24-h PM_2.5 Ambient Air Quality Standards of China, the USA, and the World Health Organization (WHO). The median E_total (the sum of the PM_2.5 exposure levels in different microenvironment and fractional time) of all students was 3014.13 (μg.h)/m³. The concentration of time-weighted average (TWA) exposure of all students was 137.01 μg/m³. The median TWA exposure level during the on-campus period (135.81 μg/m³) was significantly higher than the off-campus period (115.50 μg/m³, P = 0.013 < 0.05). Besides ambient air pollution and meteorological conditions, storey height of the classroom and mode of transportation to school were significantly correlated with children’s daily PM_2.5 exposure. Conclusions: Children in the two selected schools were exposed to high concentrations of PM_2.5 in winter of 2013 in Shanghai. Their personal PM_2.5 exposure was mainly associated with ambient air conditions, storey height of the classroom, and children’s transportation mode to school. [ABSTRACT FROM AUTHOR]