An application of low-cost sensors to monitor children's exposure to air pollution at five schools in Queensland, Australia

There are local variations in the concentration of air pollutants that may not be captured by the existing monitoring networks; however, they can be important because this is where community exposures occur. Using low-cost monitors (LCM) located at relevant community locations, such as schools, can provide information on local sources, exposure and, with the participation of the community, can help to mitigate these problems. As such, this study was conducted to assess the outdoor air quality (PM2.5 and CO) at five schools in Queensland, Australia, over a period of one year using KOALA LCMs. The results allowed us to broadly conclude on the significance of local sources, such as to show that the majority of PM2.5 in the outdoor school environments did not originate from motor vehicle emissions, being more likely from other background sources such as bushfire smoke and surface dust. By comparing the data obtained by two KOALAs, one at the roadside and the other well away from roads, we estimated that only 37% of the PM2.5 near the road originated from motor vehicles. This contrasts with the known observation that, near busy roads, over 80% of particles by number originate from vehicle emissions. This study provides a model for further investigation and helps to improve the understanding of the importance of air quality among schoolchildren and the local communities.