High air pollution is dogging the South Canterbury region and shows no sign of receding, with Timaru, Waimate and Geraldine all breaching the health guideline on Tuesday.
Timaru has experienced its 18th day of high concentrations of PM10 particulate matter this year.
The health guideline was comfortably exceeded on Tuesday with a 24-hour average concentration of 73 micrograms of suspended particulate per cubic metre of air, 23mcg above the guideline.
It was measured at the air monitoring site in Anzac Square, while 38 micrograms was measured at the monitoring site in Washdyke.
By this date last year, Environment Canterbury (ECan) had recorded 12 days of high air pollution in Timaru. Since 2001, between nine and 27 days of high pollution have been recorded by this date.
Waimate and Geraldine did not fare any better on Tuesday. Waimate experienced its fifth high air pollution day this year with a 24-hour average concentration of 52mcg.
By this time last year, no high pollution readings had been recorded in Waimate. In previous years, one to seven days of high pollution had been recorded by this date.
Geraldine experienced its third high air pollution day on Tuesday, with a reading of 53mcg.
National Environmental Standards, set by the Ministry for the Environment, are based on the health risks associated with different types of contaminants. Air pollution is recorded as "high" when the daily concentration is greater than 50 at any monitoring site within a defined airshed.
- The Timaru Herald