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Environment Protection Authority

Environmental Issues

Air - NSW overview

Australian Rail Track Corporation Report

To investigate the levels of dust generated by coal train movements in the Hunter, the NSW EPA issued the Australian Rail Track Corporation (ARTC) with a Pollution Reduction Program (PRP) that required ARTC to install dust monitoring stations along the Hunter Valley line to monitor dust generated by different train movements and report back to the NSW EPA and the public.

The aim of the report was to see if loaded coal trains emitted more particle pollution than other trains. The study found that the answer to that question was that there was no appreciable difference between the dust levels measured from the movement of loaded coal trains and other types of freight trains.

This report is just one important component of the many projects relating to air quality being undertaken by the NSW EPA. Through its Upper Hunter Air Particles Action Plan the NSW EPA has active programs in place to identify particulate sources, reduce emissions, improve air quality and reduce impacts on human health through a number of initiatives, including the Dust Stop program for all coal mines in NSW, the Upper Hunter Particle Characterisation Study and the woodsmoke reduction program for local government.

ARTC report peer review

In late May 2013 the NSW EPA requested that the ARTC report be independently peer reviewed to assess whether or not it had been undertaken with appropriate scientific rigour and the conclusions reached were scientifically valid.

The EPA received the results of an independent peer review into the report on 1 July 2013. The review, which was undertaken by Dr Luke Knibbs from the University of Queensland, found there was a major error with the statistical analysis undertaken by ARTC’s consultants and that this error affects ‘the scientific rigour of the study and the robustness of its conclusions’. The review recommends additional statistical analysis is undertaken.

View Dr Knibb’s full peer review (PDF 114KB).

The EPA engaged Professor Louise Ryan, Distinguished Professor of Statistics, UTS, on the recommendation of the NSW Chief Scientist and Engineer, Professor Mary O’Kane, to undertake a thorough independent review of the statistical analyses used in the ARTC report.

Professor Ryan found that there were some serious limitations with the statistical analyses used in the report and recommended a re-analysis of the data.

View Professor Ryan’s peer review, Review of Pollution Reduction Program 4.2 Particulate Emissions from Coal Trains (PDF 269KB).

The EPA engaged Professor Ryan to subsequently undertake re-analysis of the data in the ARTC report. Professor Ryan’s findings largely support the ARTC’s second study undertaken by Katestone Environmental Pty Ltd in May 2013.

View Professor Ryan’s re-analysis report, Re-analysis of ARTC data on Particulate Emissions from Coal Trains (PDF 600KB)

ARTC data and diesel emissions

The EPA commissioned further analysis of the ARTC data on coal train particulate matter emissions along the rail corridor in the Hunter Valley to examine the contribution that diesel emissions from locomotives have on particle levels.

The findings conclude that the particulate increases are not likely to be caused by diesel exhaust emissions from trains, rather particulate matter being stirred up from along the rail tracks as trains pass by:

  • The number of locomotives had no impact on particulate levels. This dispels, to some extent, the hypothesis that diesel exhaust explained a large proportion of the observed increases in particulate levels associated with trains passing.
  • Whether or not it had rained the previous day had a significant impact on particulate levels, indicating the increased particulate levels were caused by trains stirring up dust that had settled earlier.

It should be noted that although diesel particulates were not specifically identified in the statistical analysis, diesel combustion is a well established and quantifiable source of fine particle emissions that requires management in the broader air quality context.

View Professor Ryan's report, Additional Analysis of ARTC Data on Particulate Emissions in the Rail Corridor (PDF 2.06MB)


  • Feb 2012: EPA issues Pollution Reduction Program to ARTC, requiring the company to install air monitoring devices to record and study dust levels along tracks in the Hunter.
  • Feb 2013: ARTC releases report based on data collected over 1 year.
  • June 2013: Peer review of ARTC data finds errors in ARTC’s statistical analysis.
  • Aug 2013: Re-analysis of the data recommended, and carried out by Professor Louise Ryan.
  • Aug 2014: Professor Ryan hypothesises that diesel fuel emissions are the cause of the increases in particulate matter.
  • Sept 2014: EPA requests further analysis of the data to qualify the hypothesis.
  • June 2015: Professor Ryan’s re-analysis is completed, finding that neither coal dust nor diesel fuel have a significant effect on airborne particulate matter concentrations.
Page last updated: 15 October 2015