Author:Nick Talbot, Nick Reid, Paul Crimmins
Source:Auckland Council Research and Evaluation Unit, RIMU
Airborne particulate matter has been measured in the Auckland region since the 1960s, driven by public complaints about dust in the urban atmosphere. As the understanding of health implications of exposure to inhalable particulates increased, national statutory obligations for local authorities were introduced. These regulations led to the establishment of a network of monitoring stations across Auckland.
The Resource Management (National Environmental Standards for Air Quality) Regulations 2004 (NES-AQ, 2004) imposed a national standard for ambient concentrations of PM10 (particles of 10 micrometres and smaller). In addition to the national standard, Auckland regional targets have been introduced that also include targets for PM2.5 (particulate matter of 2.5 micrometres and smaller). The PM2.5 targets reflect current knowledge on the increased health effects of inhaling smaller particulates.
The Auckland monitoring network stations provide quality assured emissions data to assess compliance with regional and national guidelines. The stations are at representative locations – roadside, urban background, regional background sites – throughout the Auckland region. These stations provide a stable continuous dataset over years so that trends in emissions can be obtained. These trends help assess air quality improvement or degradation over time and inform Auckland Council’s five-yearly state of the environment report, which requires a review of emission trends.
A GNS Science report for Auckland Council (Davy et al., 2017) describes trends in emission sources obtained from eight years of filter measurements collected every three days from five locations across Auckland. Elemental compositions of particulate matter from particle size ranges PM2.5 and PM10 were obtained and changes in trends in different man-made and natural emission sources were identified.
This report expands the trend analysis carried out by GNS Science to evaluate the dataset for the same period for all Auckland PM10 and PM2.5 monitoring sites. Long-term trends in mass concentrations of particulate matter are described and discussed in relation to the changes in the emissions of different sources from the Auckland region. These findings are then compared to those reported in the GNS Science report.
Auckland Council technical report, TR2017/029