Auckland’s Agenda 21 fireplace ban not based on science

Time to extinguish Auckland Council’s fireplace ban for good

By David Seymour, Act Leader

Auckland Council’s attempts to ban or restrict open domestic fireplaces keep resurfacing, usually to be beaten back by public objection. It’s like driving a stake through the heart of Dracula – the Council keeps coming back.  Their Regulatory and By-laws Committee is set to reconsider the ban tomorrow.

We’ve heard claims that domestic heating emissions contribute the most to a supposed 730 premature deaths caused each year by Auckland’s air pollution, and $727m in healthcare costs.

When you hear such claims, you have to wonder about their basis.  The expression, lies, damned lies, and statistics, comes to mind.

How reliable are these estimates? No death certificates cite air quality as cause of death. How do we distinguish these influences, if really measurable, from all other forms of air pollution? Can we be sure that fireplaces in a coastal region like Auckland are a significant influence? And if we have estimates, how accurate, or uncertain, might they be?

Until recently, regardless of ones scepticism about all this, you had no way to assess the claims of those wishing to regulate the remaining open fires in Auckland out of existence.

But a few months ago 2014 Air Domain Report on New Zealand’s air quality was released by the Secretary for the Environment and the Government Statistician. And on 5 March, Parliament’s Commissioner for the Environment released a Commentary on this report.

The Commentary was extremely helpful.

The Commissioner observes that you need to decide what to worry about most, and what least. The air pollutant of most concern is particulate matter. The World Health Organisation (WHO) has four guidelines on airborne particles, for larger (PM10)) and finer (PM2.5) particulates, with guidelines for each for long-term and short-term exposure.

The most important of the WHO guidelines is for long-term finer particulate exposure, and the Commissioner notes the least important is short-term exposure to the larger particles.

But the guideline that for New Zealand’s standard for particulate matter is in fact the latter, the least important of them. We monitor the wrong thing.

The Commissioner recommends a shift to particulate regulation emphasising long-term PM2.5 exposures, observing this would sensibly widen council perspectives beyond home heating.  Winter spikes are a short-term phenomenon.

Given the trends in New Zealand’s air pollution the Commissioner concludes that “it does not look like an important environmental issue”. Auckland is comfortably below WHO guidelines for both short and long-term exposure to large and small particulates. Particulate concentrations have been declining in Auckland through the past 50 years.

Good estimates of particulate sources come from a monitoring site in Takapuna, which is considered representative of Auckland air quality. Being coastal, 40% of PM10 and 33% of PM2.5 in Auckland comes from seaspray. European Air Quality Directives allow salt and soil particulates to be subtracted from monitoring results. Doing the same here would greatly reduce the concern about all this.

Auckland’s diesel vehicle emissions are a substantial source of particulates, with a consistently large influence year-round. Interestingly, the efficiency of petrol vehicles means they barely register.

The Commissioner also comments on October 2014’s proposed by-law to reduce PM10 levels from an average of two exceedances of the PM10 rule to one. The Commissioner concludes that complying with that rule would have no detectable effect on health outcomes. So why bother?

More generally, the Commissioner’s commentary showed considerable scepticism of health impact modelling, noting impacts cannot be observed directly and thus have to be estimated from epidemiological studies. The results’ degree of uncertainty should be reported, but hasn’t been.  Comprehensive measurements are only available for PM10, but we know PM2.5 is more significant.

Furthermore, The Commissioner notes New Zealand’s mortality estimates are inconsistent with Australian studies for cities with similar PM10 measurements, which show much lower impacts.

In short, scepticism about health impacts is entirely warranted.

This brings us back to the Council obsession with eliminating the remaining domestic open fireplaces in Auckland.

Council could always consider strategies to reduce diesel emissions, but fireplaces? They just don’t matter anymore

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