SC air pollution levels hit new highs

The warmest day in South Canterbury this spring was also one of the year's most polluted.

While Timaru basked in 27C on Monday, dust blown by strong nor'west winds made the sky above the city hazy.

The dust, originating in Australia, boosted pollution measurement figures.

Geraldine and Waimate recorded their highest pollution day of the year, while Timaru recorded its second-highest day.

Environment Canterbury (ECan) air quality monitoring team leader Ross Glubb said Timaru recorded 111mcg of suspended particulate per cubic metre of air. Only a measurement of 124 on August 11 was higher.

On Monday Geraldine recorded 94 and Waimate recorded 112. Until Monday the previous year high in Geraldine was 67 on August 10. In Waimate it was 89 on August 11.

A guideline of 50mcg per cubic metre of air has been set for the contaminant of suspended particulate (PM10) for a 24-hour period. The National Environmental Standard for PM10 allows one day greater than 50.

Timaru has now exceeded the limit 38 times this year.

Mr Glubb said although the pollution level was not caused by smoke, the same health risks were associated with dust as it caused breathing problems.

While the instrument used to measure PM10 could measure any kind of particulate such as dust, pollen, smoke, or sea salt, ECan used other measurements to determine the likely source of pollution.

High pollution levels caused by home fires were usually accompanied by an increase in carbon monoxide (CO) levels in the atmosphere.

Mr Glubb said CO levels did not rise on Monday.

Meanwhile, the high temperatures and strong winds are drying Canterbury out and bringing the threat of drought closer. Forecasters say there is little chance of any significant respite from the dry conditions over the next few months.

Only 0.2 millimetres of rain has been recorded in Christchurch this month and none in Timaru, Kaikoura and Oamaru.

The dry start to September follows three months of below-average rainfall. Christchurch has had just 111.8mm of rain since June 1, about 100mm less than, and only 53 per cent of, the long-term average. Temperature records have also been broken as warm northwesterly winds bring temperatures more like summer after the country's warmest August on record.

Timaru had its hottest September day in 124 years of records on Monday, when the temperature soared to 28.2C, beating the previous highest September temperature of 26.4C, recorded last year.

Other temperature records broken on Monday include Orari with 27.5C and Cromwell 26C.

- © Fairfax NZ News