Monitoring Winter Air Pollution

PM10 exceedences (over 50 micrograms) in Canterbury air sheds

	Number of excedences each winter	Highest reading since 1999
Christchurch	14-51	220
Timaru	33-52	190
Kaiapoi	17-40	163
Rangiora	5-15	138
Ashburton	13-23	136
Waimate	0-10	95
Geraldine	1-5	62

Environment Canterbury also monitored in Kaikoura in 2002. Although the NES was breached there as well, the source of the pollution was natural (salt). In the future Environment Canterbury will be placing temporary monitoring stations in other Canterbury towns to see if the standard is breached. If the standard is breached, permanent monitoring equipment may be set up there.

Environment Canterbury has one residential monitoring site per air shed. It is a requirement under the NES to monitor on the site where pollution levels are highest or breached most often. This means that more monitoring stations per air sheds would cost ratepayers money and would not add any value.

Find out more about high air pollution readings and forecasts.
Find out more about how we monitor air pollution. 

When Do Exceedences Happen?

Almost all exceedences in air sheds where Environment Canterbury monitors happen during the months from April to September with June and July usually the months with the most exceedences.

Pollution levels are generally highest from 6pm to midnight and from 6am to 9am but vary from day to day depending on how much wind and emissions there are.