Figure 1
From: The effect of ambient air pollution on respiratory health of school children: a panel study
Indoor (open triangle) and outdoor (closed triangle) 24 hour mean PM 10 levels. The school holiday period, when no biological data was collected, is marked. Detailed event studies occurred after high pollution nights marked with arrows. The New Zealand National Environmental Standard cut-off for high pollution days is marked at 50 μg/m3. Details of monitoring sites and positions are given in the Methods section.