National Air Quality Standards
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Clean Air
Clean air is an essential ingredient for a good quality of life, as poor air quality air has a direct effect on human health and impairs our ability to lead active productive lives. In March 1997 the Government published 'The National Air Quality Strategy' in recognition of the current threats to air quality, namely from road transport. The strategy outlined how air quality would be managed on a local scale and gave rise to the National Air Quality Standards. These are a set of target levels for eight pollutant substances, recognised by Government as being of most concern, below which harmful effects were not expected to occur. The pollutants include:
- 1,3 Butadiene
- Benzene
- Carbon Monoxide
- Lead
- Nitrogen Oxides
- Ozone
- Sulphur Dioxide
- Particles (PM10).
Click on the links below for more information on the source of these pollutants and their respective health impacts:
The standards are directly linked to air quality. As such, If the levels of all these pollutants are below their respective standards, then the air quality is good. If the level of one or more of the pollutants is above its standard, then the air quality is poor. Each standard is linked to an Objective Date, stating when it has to be achieved by. The Government sought expert advice from the Committee on the Medical Effects of Air Pollutants and established the Expert Panel on Air Quality Standards to ensure that the best available knowledge would be used in the development of these standards, which protect public health.
Current National Air Quality Standards (NAQS's)
|
Pollutant |
NAQS |
Objective Dates |
|
Benzene |
16.25 µg/m3(running annual mean)
5 µg/m3 (annual mean) |
31st Dec 2003
31st Dec 2010 |
|
1, 3-Butadiene |
2.25 µg/m3(running annual mean) |
31st Dec 2003 |
|
Carbon Monoxide |
10 mg/m3 (8-hour running mean) |
31st Dec 2003 |
|
Lead |
0.5 µg/m3 (annual mean)
0.25 µg/m3(annual mean) |
31st Dec 2004
31st Dec 2008 |
|
Nitrogen Dioxide |
200 µg/m3 (hourly mean, not to be exceeded more than 18 times a year)
40 µg/m3(annual mean) |
31st Dec 2005
31st Dec 2005 |
|
Particulates (PM10) |
50 µg/m3 (24 hourly mean, not to be exceeded more than 35 times a year)
40 µg/m3(annual mean) |
31st Dec 2004
31st Dec 2004 |
|
Sulphur Dioxide |
125 µg/m3 (24 hour mean, not to be exceeded more than 3 times a year)
350 µg/m3 (hourly mean, not to be exceeded more than 24 times a year)
266 µg/m3(15 minute mean, not to be exceeded more than 35 times per year) |
31st Dec 2004
31st Dec 2004
31st Dec 2005 |
| Ozone |
100 µg/m3 (8-hour running meannot to be exceeded more than 10 times per year) |
31st Dec 2005 |
What are Averaging Times?
For any of the standards to be breached, the measured average level of one of the pollutants must be above the appropriate standard over a set amount of time depending on the pollutant in question. This time is known as the averaging time and in relation to the first standard for Nitrogen Dioxide (see above) the averaging time is 1 hour. Therefore if the average level of Nitrogen Dioxide over 1 hour exceeds 200 µg/m3 then this constitutes a breach of the standard. 18 hourly exceedences are currently allowed every year for Nitrogen Dioxide.
Where do the Standards Apply?
The standards apply to outdoor locations where it is possible that members of the public will be exposed over sufficient time for the onset of harmful effects, such as exacerbating asthma. Typical locations include residential areas, hospital grounds, playing fields and school fields. They do not currently apply to occupational outdoor locations.
Do the Standards Change?
The standards are under continual review and thanks to an increase in scientific understanding, have become more stringent over time. New standards for Polycyclic Aromatic Hydrocarbons and more stringent standards for Particles (PM10) will soon be in force. The standards for Carbon Monoxide and Benzene have recently been strengthened and it is quite possible that additional and or tougher standards will be introduced for other pollutants in the future.
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