Nitrogen dioxide exposure at early childhood centres next to high- and low-traffic roads in Auckland, New Zealand

New Zealand lacks licensing restrictions with regard to location of early childhood centres (ECCs) and hence, many young children may be exposed unnecessarily to high levels of traffic-related air pollution. This study aims to investigate whether there is a significant difference in nitrogen dioxide (NO2) concentrations at ECCs located along high-and low-traffic roads. It explores whether asthma medication usage (as a proxy for respiratory health impacts) while attending ECCs differs between children attending high-compared with low-traffic ECCs. Of the 21 ECCs chosen for the study, 10 ECCs and 11 ECCs were located near high-and low-traffic roads, respectively. Over a 16-week period, six NO2 diffusion tube deployments were made indoors and in the outdoor play area at each ECC and on the near and far side of the road adjacent to each ECC. Asthma medication usage among children was recorded throughout the period of observation. Significantly higher outdoor NO2 concentrations were observed at high-compared with low-traffic ECCs with means of 24.6 and 17.1 mug/m3, respectively. Indoor NO2 concentrations were significantly lower than in the outdoor play areas with means of 16.5 and 20.1mug/m3, respectively. Among children using asthma medication one or more times at the ECCs during the study, over two-thirds (71%) were attending high-traffic ECCs. Children attending high-traffic ECCs may be at higher risk of adverse health impacts associated with exposure to traffic-related pollution. Legislation on ECC licensing needs to be introduced in order to ensure that young children are not unnecessarily adversely affected by traffic-related pollution.