Air pollution

 
 

Air Quality Objectives

The standards adopted in the UK are the National Air Quality Standards, part of the National Air Quality Strategy adopted by the government in January 2000.

View the latest bulletin to see current air quality measurements in Westminster.

PollutantObjectiveMeasured asTo be achieved by
Benzene16.25 µg/m3 (5 ppb)Running Annual Mean31/12/03
1,3-Butadiene2.25 µg/m3 (1 ppb)Running Annual Mean31/12/03
Carbon monoxide11.6 mg/m3 (10 ppm)Running 8 Hour Mean31/12/03
Lead0.5 µg/m3Annual Mean31/12/04
0.25 µg/m3Annual Mean31/12/08
Nitrogen dioxide*200 µg/m3 (105 ppb)
Not to be exceeded more than 18 times per year		1 Hour Mean31/12/05
40 µg/m3 (21 ppb)Annual Mean31/12/05
Nitrogen Oxides**(V) 30 µg/m3 (16 ppb)Annual Mean31/12/00
Ozone100 µg/m3Running 8 hour Mean
Daily maximum of running 8 hr mean not to be exceeded more than 10 times per year		31/12/05
Particles (PM10)50 µg/m3
Not to be exceeded more than 35 times per year		24 Hour Mean31/12/04
40 µg/m3Annual Mean31/12/04
Sulphur dioxide266 µg/m3 (100 ppb)
Not to be exceeded more than 35 times per year		15 Minute Mean31/12/05
350 µg/m3 (132 ppb)
Not to be exceeded more than 24 times per year		1 Hour Mean31/12/04
125 µg/m3 (47 ppb)
Not to be exceeded more than 3 times per year		24 Hour Mean31/12/04
(V) 20 µg/m3 (8 ppb)Annual Mean31/12/00
(V) 20 µg/m3 (8 ppb)Winter Mean (01 October - 31 March)31/12/00
Notes:
µg/m3 - micrograms per cubic metre
mg/m3 - milligrams per cubic metre
ppb - parts per billion
ppm - parts per million
* The objectives for nitrogen dioxide are provisional
** Assuming NOx is taken as NO2
(V) These standards are adopted for the protection of vegetation and ecosystems. All of the remainder are for the protec