Air Quality Standards

The following table shows the pollutants as classified by the Air Quality (Wales) Regulations 2000 and (Amendment) (Wales) Regulations 2002 (external link) for the purpose of Local Air Quality Management. These Air Quality Regulations have adopted into UK law the limit values required by EU Daughter Directives on Air Quality.

The permitted atmospheric levels have been determined by what is known about their effect on both human and environmental health.

The objective expresses the level of pollutant that is permitted in the air over a given period of time. This level is expressed as:

  • µgm³ - micrograms per cubic meter, where one micorgram is one millionth of a gram.
  • mgm³ - milligrams per cubic meter, where one milligram is one thousandth of a gram.

The table also shows the date by which this level should be achieved.

Pollutant Air Quality Objective Concentrations Measured as Target Date
Benzene 16.25 µgm³ Running Annual Mean 31.12.2004
5.00 µgm³ Annual Mean 31.12.2010
1,3-Butadiene 2.25 µgm³ Running Annual Mean 31.12.2003
Carbon Monoxide 10.0 mgm³ Maximum Daily Running 8 Hour Mean 31.12.2003
Lead 0.50 µgm³ Annual Mean 31.12.2004
0.25 µgm³ Annual Mean 31.12.2008
Nitrogen Dioxide 200 µgm³ 1 Hour Mean
Not to be exceeded more than 10 times a year		 31.12.2005
40 µgm³ Annual Mean 31.12.2005
Ozone 100 µgm³ Running 8 Hour Mean
Not to be exceeded more than 10 times a year		 31.12.2005
Particulate Matter PM10 50 µgm³ 24 Hour Mean
Not to be exceeded more than 35 times a year		 31.12.2004
40 µgm³ Annual Mean 31.12.2004
Sulphur Dioxide 266 µgm³ 15 Minute Mean
Not to be exceeded more than 35 times a year		 31.12.2005
350 µgm³ 1 Hour Mean
Not to be exceeded more than 24 times a year		 31.12.2004
125 µgm³ 24 Hour Mean
Not to be exceeded more than 3 times a year		 31.12.2004

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