August air not as bad as usual
Less pollution in mild winter
A mild winter has meant less air pollution in Central Otago and Arrowtown this year. An Otago Regional Council (ORC) air quality report shows Alexandra, Clyde and Arrowtown had fewer high pollution days last month compared with usual August figures. It is considered a high pollution day, or exceedence of the National Environmental Standard for air pollution, if average daily PM10 concentrations are over 50 micrograms per cubic metre of air, or 50ig/m3. Cromwell recorded exceedences in August. Otago Air Zone 1, which includes the four towns, has traditionally recorded some of the worst winter air pollution in New Zealand. ORC director of environmental information and science John Threlfall said ‘‘there has been an improvement (in air quality) this year but we can’t exclude the fact the weather has been milder.’’
10 The winter has been one of the mildest since 2006. Arrowtown, which recorded six exceedences in August last year, recorded none last month. Part of the improvement in air pollution could be linked to more than 100 houses in the town having open fires removed and upgraded to efficient heating. ‘‘There’s clearly less smoke in the air and we know there are less coal and old fires [being used],’’ he said. However, the council received several complaints from Arrowtown residents in the first week of July about pollution during a cold snap. For 16 consecutive days, between June 29 to July 14, Arrowtown recorded high pollution days, with the highest recording of 147ig/m3 on July 3. ‘‘When it gets really cold people are going to crank up their fires,’’ Mr Threlfall said. There was still a lot to do to decrease air pollution in the area, he said.
Typical: A typical winter’s day of smog over Clyde and Alexandra last week.