Air quality trends
We measure airborne particles, also known as particulate matter (PM) at 10 monitoring sites across Canterbury. PM2.5 refers to particles smaller than 2.5 micrometres in size. PM10 includes all the PM2.5 particles and larger coarse particles up to 10 micrometres.
We use several measures to show changes in PM10 and PM2.5 over time, from the number of high pollution events to the highest daily and annual average concentrations.
In some locations, the monitoring site has been moved, which may affect the trends. More details about site locations can be found in the latest air quality environmental snapshot report (PDF File, 3.73MB).