Oct 24 2019

Power station particulate emissions: Flawed claims re-emerge

This year unsubstantiated claims about the health effects of coal-fired power stations in New South Wales have emerged despite a lack of supporting data and independent peer-reviewed assessment.

The claims, particularly those around the impact of fine particulate matter (PM2.5), are concerning and resurfaced last week when advocacy group, the Australasian Centre for Corporate Responsibility, sought to link NSW power stations to early deaths.

The claims on premature deaths stem from a non-peer reviewed study – the Ewald Report – which was commissioned last year by a green advocacy group, Environmental Justice Australia.

The Australian Energy Council commissioned Environmental Risk Sciences (EnRiskS), an independent qualified consultant, to peer-review the Ewald report. It found the report used “flawed” analysis that was “not based on good science” to try and link five NSW power stations to premature, yet unverified, deaths.

The EnRiskS review summarises that the Ewald report is “poorly referenced, with many sections providing statements with no references as to the basis of such statements. The Ewald report is not sufficiently transparent, hence the detailed calculations undertaken cannot be checked and verified. This is especially important where the conclusions of the report make claims regarding specific sources being directly attributable/responsible for mortality.”

The EnRiskS review identified a number of specific issues with the Ewald report. These were:

  • the area evaluated appeared to be random and does not relate to any method for estimating particulate exposures;
  • the baseline incidence for mortality is only estimated, not based on available age specific data; and
  • current science does not support the incidence of type 2 diabetes or low birth weight as “core health outcomes” part of the claims made in the Ewald report.

In assessing PM2.5, EnRiskS reported that: “It is important that any assessment of the health impacts from any one source is also considered in the context of other key urban sources. This would assist in better understanding and contextualising the health impacts of these sources.”

To put this into context, the NSW Office of Environment and Heritage (OEH) published a study in March this year that identified that natural sources contributed 60 per cent of PM2.5 emissions, while 40 per cent came from man-made sources, with 31 per cent of those emissions coming from wood heaters, 26 per cent from industry, 19 per cent from road vehicles and only 17 per cent from power stations[i].

Further claims made last week were that the EnRiskS report itself points to a specific number of early deaths from power stations (based on a 2003 modelling cited in Malfroy et al 2005). This is not correct. The EnRiskS report clearly attributes the health impacts to all sources of PM2.5, not just power stations. As noted above, there are a range of sources and attempting to make definitive statements is fraught with issues and likely to misrepresent the data.

Overall EnRiskS found that its “review of the Ewald report has identified a range of issues that call into question the outcomes presented as well as the level of certainty placed on the outcomes presented.”

Elsewhere it comments that: “It is important to note that the Ewald report consistently makes statements that the assumptions and approach adopted are ‘certain’. This is not the case. The approach adopted has a very high level of uncertainty, which is not recognised or considered in the report.”

Importantly, the EnRiskS report clearly outlines what would need to be considered for a proper and robust assessment of the potential health impact of emissions from coal-fired power stations. This would involve:

  • Clearly defining and understanding the populations in relation to these emissions – and having a good basis for determining those populations, including making sure the areas coincide with the populations and regions considered in the estimation of exposure.
  • Use of current OEH modelling of emissions, obtaining information relevant to both primary and secondary particulates (as derived from current coal-fired power stations) as an average in various population areas of interest.
  • Evaluation of key health endpoints that relate to PM2.5 exposure, preferably those that are causally associated, or where there is sufficient consistent weight of evidence to consider the association to be strong.
  • To evaluate these health endpoints, data from NSW Health should be obtained to ensure that the baseline health statistic used are the most current and relevant to the population ages and health endpoint being evaluated.
  • Where such an assessment is undertaken all the calculations should be provided so that the assessment is robust and transparent, and others can verify the calculations.
  • The assessment should also provide context to the health impacts evaluated and considered, with impacts from other key sources in urban areas also considered so that the outcomes can be weighed up against other types of common exposures. This is especially the case for pollutants like PM2.5which come from a range of sources including naturally occurring and man-made sources (diffuse and localised).

These public exaggerations and distortions are alarmist and appear to be part of a broader agenda to discredit fossil fuel power sources.    

Air pollution from a range of sources has the potential to impact on public health. But investigations and assessments of potential health risks from air emissions should be undertaken through independent, peer-reviewed studies which present a complete picture of the overall health risk from a range of sources.

The fact is that the Australian population enjoys remarkably clean air by world standards, and of the small amount pollution there is, it is dominated by other causes.

Emissions in Australia are monitored by science-based regulators. Any regulation of air quality then needs to be based on robust, peer-reviewed scientific data and assessments. The EnRiskS report is an important reminder of the need to undertake such thorough assessments. The work also helps to highlight the way in which data can be manipulated or misrepresented to pursue an agenda.

Read the full EnRisks Review here.

[i] https://nespurban.edu.au/wp-content/uploads/2019/05/Major-Source-Contributions-to-Ambient-PM2.5-and-Exposures-within-the-New-South-Wales-Greater-Metropolitan-Region.pdf

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