Air pollution and amnesia
From Sam Judd, in today’s Herald:
In 2009, Auckland had 23 micrograms of PM10 (airborne particles smaller than 10 micrometres) per cubic metre of air as an annual average – 3 above the WHO guidelines of 20. …
The much smaller Hamilton is one behind at 22 (which is our national average), wind doesn’t seem to help Wellington which is at 21 and the notoriously smoggy Christchurch (who has been banning woodfire use periodically since 2010) sits at 20.
Most embarrassingly, despite the fact that their cities are far bigger and more concentrated than ours, Australians enjoy air at 13 PM10 and the bustling metropolis of Syndey sits at only 12.
From the Herald, last September 28
WHO’s air quality guidelines recommend a maximum of 20 micrograms of PM10 per cubic metre of air on average but Auckland with 23, Hamilton on 22 and Wellington on 21 all exceeded that.
The data has been replaced by 2010 numbers which showed all New Zealand main centres within the WHO safety guidelines of no more than 20 micrograms of PM10 particles per cubic metre of air with the exception of Dunedin which had been the only compliant New Zealand city according to the previous figures.
The World Health Organisation has removed data from its website that suggested New Zealand cities’ air quality was poorer than any major city in Australia
The actual figures were: 15μg/m3 for Auckland, 13 for Hamilton, 11 for Wellington. It just doesn’t make sense that traffic-related air pollution would be much higher in Wellington than in Melbourne or Sydney, which are much larger, also choked with traffic, and less windy. If it sounds too good to be true, it’s probably worth checking.
If you want to worry about actual air pollution in New Zealand, it’s the south-east that’s the place: Timaru is the worst (32 μg/m3), and some Otago towns and cities are also bad. It’s not primarily traffic that’s the problem, but wood smoke. Christchurch used to be fairly high, but has improved a lot.
Thomas Lumley (@tslumley) is Professor of Biostatistics at the University of Auckland. His research interests include semiparametric models, survey sampling, statistical computing, foundations of statistics, and whatever methodological problems his medical collaborators come up with. He also blogs at Biased and Inefficient See all posts by Thomas Lumley »