4 Ambient Air Quality Guidelines and Standards
The Ministry for the Environment has promulgated national environmental standards for air quality. These standards were released in October 2004, and for several major contaminants they replaced the Ambient Air Quality Guidelines 2002. Both the national environmental standards and the Ambient Air Quality Guidelinesare set to protect human health. The national environmental standards allow a number of exceedences per year but must be complied with by 1 September 2005. Ministry for the Environment guidelines for the various air pollutants monitored as part of the GEMS/AMIS programme are given in Table 1.
Total suspended particulate (TSP) does not have a guideline value in the Ministry for the Environment's Ambient Air Quality Guidelines as it does not have a recognised effect on human health. The criteria applied to TSP is 60 µg/m3 (seven-day average) previously applied by the Ministry of Health. This has been superseded by the Ministry's Ambient Air Quality Guidelines but is useful for analysing the results of the monitoring data.
Table 1: National environmental standards, guidelines and regional targets
|
Air pollutant |
National environ-mental standards 2004 |
Ministry for the Environment Ambient Air Quality Guidelines 2002 and other |
Averaging period |
National environmental standards permissible excess |
|---|---|---|---|---|
|
Carbon monoxide |
10 mg/m3 |
30 mg/m3 |
8-hour average 1-hour average |
One 8-hour period in a 12-month period |
|
Nitrogen dioxide |
200 µg/m3 |
100 µg/m3 |
24-hour average 1-hour average |
9 hours in a 12-month period |
|
Sulphur dioxide |
350 µg/m3 570 µg/m3 |
120 µg/m3 |
24-hour average 1-hour average 1-hour average |
9 hours in a 12-month period Not to be exceeded at any time |
|
Benzene - Year 2000 - Year 2010 |
10 µg/m3 3.6 µg/m3 |
Annual average Annual average |
||
|
1,3-Butadiene |
2.4 µg/m3 |
Annual average |
||
|
Fine particulate (PM10) |
50 µg/m3 |
20 µg/m3 |
Annual average 24-hour average |
One 24-hour period in a 12-month period |
|
Total suspended particulate (TSP) |
60 µg/m3 (MoH) |
7-day average |
||
|
Lead |
0.2 µg/m3 |
3-month average |
