Sources of indoor air pollution at a New Zealand urban primary school; a case study

Özet

Children are particularly vulnerable to the health effects of air pollution and as they spend a large proportion oftime at school, this is an important environment for children's exposure to air pollution. Understanding thefactors that influence indoor air quality in schools is critical for the assessment and control of indoor air pollution. This study analysed the concentration and sources of air pollution at an urban primary school (5–11years) in Wellington, the capital of New Zealand. Over a three-week period during spring, indoor measures ofparticulate matter ($PM_{2.5}$, $PM_{10}$), temperature, humidity, carbon dioxide ($CO_2$) and nitrogen dioxide ($NO_2$) weretaken and hourly air particulate matter samples ($PM_{2.5}$, $PM_{10}$) were collected inside and outside for elementalspeciation analysis. Indoor PM10 concentrations during the school day were significantly (p < 0.001) higherthan outdoor concentrations 30.1 (range 10.0–75.0, SD 1.9) μg $m^{-3}$ c.f. 8.9 (range < 1.0–35.0, SD 6.8) μg $m^{-3}$.Elemental analysis and receptor modelling of PM samples showed that indoor PM10 was primarily composed ofcrustal matter (soil) elements, possibly brought in on children's footwear. The primary driver of indoor $PM_{2.5}$,was from the infiltration of outdoor pollutants inside, with by-products of motor vehicle emissions the maincontributor to indoor $PM_{2.5}$, There is a need for mitigation strategies to reduce exposure to indoor air pollution atschool, such as improved cleaning methods, reducing the use of carpet in schools and improved ventilation. Thefindings from this study will be applicable to many other schools and public buildings with high foot traffic.