Timaru has experienced its 34th high air pollution day this year, on a day when both Geraldine and Waimate breached Environment Canterbury's health-based guideline.
ECan's guideline of 50mcg was exceeded on Thursday with a 24-hour average concentration of 52 micrograms of suspended particulate per cubic metre of air, measured at the monitoring site in Anzac Square.
It recorded 88 per cent of the PM10 (particulate matter) as coming from home heating sources in Timaru.
Geraldine experienced its fifth day of high pollution, at 51mcg, with ECan estimating 92 per cent of PM10 emissions came from home heating sources.
Waimate experienced its eighth breach, with a reading of 54mcg.
PM10 refers to particulate matter in the air that is smaller than 10 micrometers in diameter.
It is generally emitted from the combustion of fuels such as wood and coal (from home heating and industry) and petrol and diesel (from vehicles).
- The Timaru Herald