6 Methods
6.1 Quality assurance
All monitoring services are undertaken by Watercare Services Ltd in accordance with the Ministry for Environment's Good Practice Guide for Air Quality Monitoring and Data Management and wherever applicable the appropriate Australian/New Zealand and US EPA monitoring methods.
Watercare Laboratory Services is accredited by IANZ (International Accreditation New Zealand) and since October 2003 has held accreditation for the following methods:
- Australian Standard AS 3580.7.1 - 1992 'Method 7.1: Determination of Carbon Monoxide - Direct Reading Instrumental Method'.
- Australian Standard AS 3580.5.1 - 1993 'Method 5.1: Determination of Oxides of Nitrogen - Chemiluminescence Method'.
- Australian Standard AS 3580.4.1 - 1990 'Method 4.1: Determination of Sulphur Dioxide - Direct Reading Instrumental Method'.
- US EPA Method 40, Part 50, Appendix J 'Reference Method for the Determination of Particulate Matter as PM10 in the Atmosphere'.
As part of the GEMS/AMIS programme, Watercare Laboratory Services provides the following monitoring services:
- Instrument operation, calibration and maintenance. This includes the use of automatic daily calibration systems for all continuous ambient gas monitors ensuring that the requirements of the relevant Australian Standards for weekly calibration of continuous analysers.
- Site maintenance as well as, when necessary, commissioning new sites and decommissioning old sites.
- Data logging, polling, checking, rescaling, validation, ratification and reporting. This encompasses the entire data quality assurance process ensuring that the final dataset reported is fit for the purpose of the GEMS/AMIS programme.
6.2 Analytical methods
6.2.1 Carbon monoxide
Measurements are made in accordance with AS 3580.7.1 - 1992 'Determination of Carbon Monoxide - Direct Reading Instrumental Method'. The performance of the instruments are checked using an automatic calibration system ensuring compliance with the method which requires instrumentation to be calibrated on a weekly basis.
The instruments themselves are infra red absorption gas analysers which continuously measure carbon monoxide. This allows data to be analysed and reported over a variety of average periods including 10 minutes, 24 hours and one year.
6.2.2 Nitrogen oxides
Measurements are made in accordance with AS 3580.5.1 - 1993 'Determination of Oxides of Nitrogen - Chemiluminescence Method'. The performance of the instruments are checked using an automatic calibration system ensuring compliance with the method which requires instrumentation to be calibrated on a weekly basis.
The instruments themselves are chemiluminescence gas analysers which continuously measure nitrogen oxides. This allows data to be analysed and reported over a variety of average periods including 10 minutes, 24 hours and one year.
6.2.3 Sulphur dioxide
Measurements are made in accordance with AS 3580.4.1 - 1990 'Determination of Sulphur Dioxide - Direct Reading Instrumental Method'. The performance of the instruments are checked using an automatic calibration system ensuring compliance with the method which requires instrumentation to be calibrated on a weekly basis.
The instruments themselves are UV fluorescence gas analysers which continuously measure sulphur dioxide. This allows data to be analysed and reported over a variety of average periods including 10 minutes, 24 hours and one year.
6.2.4 Volatile organic compounds
VOCs are measured each quarter (January-March, April-June, July-September and October-December) in accordance with Watercare's Air Quality Group Test Method T114 (ref NIOSH Methods 1500 and 1501).
VOC samples are taken using passive (3M) sampling badges which are exposed for a three-month period. The VOCs diffuse on to the badges which are coated with activated carbon. Following exposure the samples are forwarded to AgriQuality who extract the VOCs using carbon disulphide and analyse them using GC-MS.
Note: Determination of 1,3-butadiene over a three month exposure period is not reliable. Investigations have determined that samples are unstable when held above -4°C (OSHA Method 54, NIOSH Method 1024), with significant desorption occurring. Technical information supplied with 3M badges reports a 10% loss of 1,3-butadiene over three weeks storage at room temperature. Due to the potential for error over a three-month exposure period, 1,3-butadiene has not been analysed and reported.
6.2.5 Particulate matter (PM10)
Measurements are made in accordance with the US EPA Equivalent Method for measuring PM10 EQPM-1102-150 'Thermo Andersen Series FH62-C14 Continuous PM10 Ambient Particulate Monitor'. This method was designated as an Equivalent Method by the US EPA in accordance with 40 CFR Part 53 on 11 December 2002.
The Thermo Andersen FH62-C14 is fitted with a size-selective PM10 head and measures particle mass as it accumulates during sampling. As a result the instrument is able to record and output real-time measurements of PM10 data which allows measurements to be reported over a variety of average periods, including; 10 minutes, 24 hours and one year. The inlet temperature of all beta-gauges operated by the Ministry for the Environment is 40°C.
6.2.6 Particulate matter (TSP)
Measurements of TSP are made in accordance with Watercare's Air Quality Group Test Method T101. It is a gravimetric method of measuring particulates and is modelled upon the High Volume sampler method. The technique has been used to provide TSP data at existing GEM/ AMIS sites since 1982.
The equipment used to measure TSP is quite basic and involves ambient air being pulled through a glass fibre filter by a pump with a gas meter being used to measure the air volume drawn through the filter. The filter is weighed before and after sampling. The TSP concentration is determined from the weight of particulates collected and the air volume sampled.
6.2.7 Lead
Lead is sampled during the winter months, June-August, using the same instrumentation used to measure TSP according to Watercare's Air Quality Group Test Method T101. This is a gravimetric technique used to measure particulates and is modelled upon the high volume sampler method. The technique has been used to provide TSP data at existing GEM's sites since 1987.
Analysis of lead is performed according to Watercare Laboratory Services according to US EPA Methods 3051 and 200.7. This involves taking a composite of the weekly TSP filters exposed during each winter month and digesting them all, using mixed acid digestion, into a single sample. This sample is then analysed for lead using the technique of Inductively Coupled Plasma Optical Emisssions Spectrometry (ICP-OES). The concentration of lead sampled during the month is then determined from the amount of lead detected and the total volume of air sampled during the respective month.
