Dunedin, Christchurch and Timaru have worse air pollution than Auckland, World Health Organisation (WHO) data shows.
A report on outdoor air quality in 1600 cities across 91 countries recorded 2012's annual mean concentrations of fine particulate matter: particles smaller than 10 micrometres in diameter (PM10) per cubic metre of air.
Timaru recorded the highest PM10 value in New Zealand of 28 micrograms per cubic metre, nearly twice that of Auckland's 15 and Dunedin's 18. Christchurch came in second at 23.
WHO Air Quality Guidelines recommend annual mean PM10 values of no more than 20 micrograms per cubic metre.
PM10 values recorded in New Zealand were minor compared to global values. Pakistan recorded the top two values, with 540 and 448.
Data on air quality in New Zealand was gathered by regional councils, and was collated by the Ministry for the Environment. Dunedin decreased from 25 to 18 between 2010 and 2012.
The ministry sets a National Environmental Standard for PM10 of 50 micrograms per cubic metre of air, averaged over 24 hours. Nights where this is exceeded are classed as high pollution nights.
Last year measuring stations in St Albans and Woolston in Christchurch had 13 and 21 high pollution nights respectively.
Timaru had 30 high pollution nights, while Rangiora and Kaiapoi had 10 and 11 respectively.
The Woolston station, Timaru and Geraldine have recorded one high pollution night this year.
Environment Canterbury is responsible for reducing high pollution nights in Christchurch, Timaru, Ashburton, Kaiapoi and Waimate to three a year by September 2016, and once a year by September 2020.
- The Southland Times
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