Pat Palmer: Air quality PM10 standards and health in Christchurch

In May the Press published a summary of a Ministry for the Environment (MfE )report extolling the improvements in health which have been achieved in New Zealand by the reduction in concentrations of PM10 in the air we breathe. 

The report said an 8 per cent nation-wide reduction between 2006 and 2012 resulted in 14 per cent fewer deaths and 15 per cent fewer hospital admissions from man made air pollution. Other reports from the Ministry say that respiratory health is the main effect. These numbers came from a model relating numbers of premature deaths and hospital admissions to measured or estimated concentrations of PM10.

What the Press (Fairfax NZ) report did not say was that the health impacts were not derived from hospital records or mortality statistics (which seems strange seeing that one of the contributors to the report was the official Government Statistician). This is "I say so" science. The sort the church authorities relied on to prove the sun went round the earth each day. Not the "You can see so" science of Galileo and Copernicus.

In 2011 Wilton and Familton from Environment Canterbury (ECan) reported to the Conference of the Clean Air Society of Australia and New Zealand on "Health benefits of cleaning up Christchurch's air". ECan air quality scientists have gathered very good records of PM10 concentrations in Christchurch going back for over twenty years. During that time, concentrations have about halved, largely due to the ECan campaign against use of open fires and log burners.

Using essentially the same model and data as the MfE report, Wilton and Familton estimated that the number of PM10 deaths in Christchurch dropped from 275 in 2001 to 180 in the years from 2007 to 2010. A drop of nearly 100 deaths. The actual death rates from respiratory disease (COPD) do not show this dramatic decline estimated by Wilton and Familton. About 200 deaths from COPD occur in Christchurch each year. They hover round 5.7 percent of all deaths throughout the period. It must be concluded that reducing PM10 in Christchurch has not reduced the number of premature deaths as predicted by the MfE model, and as claimed in their report.  

This should come as no surprise. The MfE sponsored HAPiNZ Christchurch Pilot Study leads to the conclusion that wood smoke from home fires is not an important cause of premature death in Christchurch. The MfE and ECan science advisers have ignored this conclusion from their own expensively obtained data. They prefer their "say so" science.

Similarly with the claimed reductions in admissions to hospital for pulmonary disease resulting from reductions in PM10 concentrations.  There must be a mine of information in the Christchurch Hospital records. This is not available to the public. When the Association for Independent Research (AIR) asked the Canterbury District Health Board to find out what their own data showed, the Board decided instead to accept the ECan report on the matter

ECan has conducted a very expensive experiment, paid for by rate-payers and householders over the past 20 years. It has reduced PM10 concentrations by putting out home fires. This has gone part way towards achieving the MfE air quality standards. It has shown that wood smoke from home fires has not been killing hundreds of Christchurch people. The evidence is clear that meeting the standard by imposing even further restrictions on home heating will not lead to health benefits.

So we see where "say so" science has got the MfE, ECan, and the people of Christchurch. It is past high time for ECan to ask the Minister for the Environment to seriously question the usefulness of this apparently useless standard. However ECan sees its responsibility is to "meet a maximum of three high-pollution days a year by September 2016", as ruled by the MfE (Press May 24, p A4).

It is interesting to consider how ECan, which was originally set up as a local body to protect Christchurch from flooding, has morphed into a non-elected policeman for the Ministry for the Environment. Government of the people indeed, paid for by the people, but unfortunately not for the health of the people.

Pat Palmer is a foundation member of Association for Independent Research (AIR) who has been studying the relationship between air pollution in Christchurch and claimed health effects since 1996.