Continuous daily monitoring by the Otago Regional Council began in Arrowtown in July 2006.
The most common pollutant is PM10 - particulate matter with a diameter of less than 10 microns. These very small particles are produced from partially burnt fuel.
In Arrowtown, as in most other Central Otago towns, they are emitted from the solid fuel burners used for domestic heating as well as outdoor burning.
This weekly graph shows the average daily levels of PM10 recorded at the monitor in Arrowtown during the previous week. Particulate levels vary due to how much smoke is in the air and also changing weather conditions.
Temperature inversions tend to trap polluted air near the surface while windy conditions help disperse particulates into the atmosphere.
In 2004, the Ministry for the Environment introduced the Air Quality National Environmental Standards (NES).
This is a national regulation designed to protect human health, as these particles are associated with adverse respiratory effects. All PM10 values are measured and reported in micrograms per cubic metre of air (ug/m3).
The NES allows a daily average of up to 50ug/m3. The role of the ORC is to achieve air quality that does not exceed the standard more than once a year.
There are 11 air quality monitors placed throughout Otago.
Results are reported weekly and can be found on the ORC website at www.orc.govt.nz/airinfo
