1 Summary
Air pollutants arise from a number of different sources. Fine particles (PM10) arise from stationary and mobile combustion sources, principally domestic heating, industrial processes and vehicle emissions (as well as natural processes such as soil erosion and sea salt). Sulphur dioxide is produced from the burning of fossil fuels, particularly coal and oil. Carbon monoxide is a product of incomplete combustion of carbon containing fuels, especially from motor vehicles. Volatile organic compounds (VOCs) are organic chemicals, such as hydrocarbons, that are closely tied to vehicle emissions and many industrial processes. Historically, lead was a petrol additive but since the significant reduction of lead in petrol from 1996, levels have declined in New Zealand.
The (Global Environmental Monitoring System) GEMS monitoring sites were established to measure key air pollutants associated with adverse effects on people's health and wellbeing. This report presents the 2004 data set for the GEMS sites in Auckland and Christchurch, New Zealand. The GEMS sites include some of the longest running air quality monitoring sites in New Zealand. Various air quality monitoring has been undertaken at the Gavin Street, Penrose site in Auckland since 1964. These sites were established to determine the effect of policies for air quality management and are important for recording trends in pollution level trends in New Zealand. The GEMS sites have provided continuity in monitoring data for Auckland and Christchurch, and a snapshot of air quality for two of New Zealand's largest cities.
The two Auckland monitoring sites include a site dominated by residential and vehicle emissions (Kowhai Intermediate School, Kingsland) and a site representative of vehicle and industrial emissions (Gavin Street, Penrose). This report also includes data from the Kelly Street, Mt Eden site which was decommissioned and replaced by Kowhai in October 2004 after seven months parallel monitoring. The Greers Road, Burnside site in Christchurch is located within a residential area and represents emissions from domestic properties. The other Christchurch site (Cole's Place, St Albans) is also in a residential area and measures additional pollutants.
Five ambient air quality standards for carbon monoxide, nitrogen dioxide, ozone, PM10 and sulphur dioxide were promulgated in October 2004. These standards are the minimum requirements that outdoor air quality must meet to guarantee a set level of protection for human health and the environment. The ambient standards are based on existing ambient air quality guidelines. Guideline levels for pollutants (and averaging periods) not covered by the standards still apply.
The monitoring for carbon monoxide undertaken at Burnside, Christchurch showed concentrations were below the air quality 1-hour standard and 8-hour guideline during 2004. The nitrogen dioxide air quality 1-hour standard and 24-hour guideline was not exceeded at any site during 2004. Neither site in Auckland or Christchurch experienced exceedences of the sulphur dioxide air quality 1-hour standard and 24-hour guideline. There were no exceedences of the 24-hour fine particles air quality standard at Kelly Street (Mt Eden), Gavin Street (Penrose) or Kowhai Intermediate (Kingsland) during 2004. However, at Greers Road, Burnside, there were 25 exceedences of the 24-hour standard, mainly during the winter months from July to August 2004. These exceedences are likely to have resulted from the combination of home heating emissions and meteorological conditions such as temperature inversions. At all sites the six month concentrations of VOCs as benzene were below the guideline value of 3.6µg/m3 to be achieved by 2010.
The continuous monitors performed well with data capture rates (instrument availability including calibration data) of well over 90% for all sites. Valid NO2 data (excluding calibrations and other invalid results) from the Burnside site was just below 90% due to communication difficulties with the instrument and an air conditioning failure. Unfortunately, the filters used for lead analysis were misplaced in storage and have been unavailable for lead analysis.
