Children's exposure to sized-fractioned particulate matter and black carbon in an urban environment

Abstract

Fine air particulate matter (PM2.5) is currently one of the major environmental issues influencing people's health. The first step for assessing the health effects of inhaled PM2.5 is based on the evaluation of the human exposure levels. The main objective of this study is to quantify children's daily exposure to sized-fractioned PM2.5 and Black Carbon (BC) in an urban environment. Children from Lisbon metropolitan area carried portable monitoring equipment during three days and recorded the time spent in their activities and respective microenvironments (MEs). The average exposure to PM2.5 (19 μg/m3) was higher than that registered by the nearest fixed urban background station (11 μg/m3), evidencing the importance of assessing the personal daily exposure. The average exposure to PM1, PM0.5 and PM0.25 was 14 μg/m3, 11 μg/m3, and 7.7 μg/m3, respectively. Time-activity pattern records showed that children spent more than 80% of their time indoors, especially at home (55%) and in the classroom (22%), where they received 44% of the daily BC dose. Although commuting only accounted for 5.0% of the daily time, children inhaled 23% of their daily BC dose when travelling in rush hours to school. Time series analysis of the BC concentrations showed an average of 1.3 μg/m3, with high peak levels in underground parking lots (63 μg/m3), during charcoal grills (53 μg/m3), and when candles were burning (6.6 μg/m3). This work highlights the importance of urban planning to reduce children's exposure to traffic emissions, combined with awareness-raising actions for citizens concerning the impact of indoor sources.