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UK national air quality objectives |
Substance Averaging Period Objective Levels Date by which objective to be metBenzene running annual mean 16.25 µg/m 3 ( 5 ppb) 31 December 2003 annual mean 5 µg/m 3 (1.54 ppb) 31 December 2010 1,3-Butadiene running annual mean 2.25 µg/m 3 (1 ppb) 31 December 2003 Carbon monoxide running 8-hour mean 10 mg/m 3 (8.6 ppm) 31 December 2003 (CO) Lead annual mean 0.5 µg/m 3 31 December 2004 annual mean 0.25 µg/m3 31 December 2008 Nitrogen dioxide 1-hour mean 200 µg/m 3 (105 ppb), not be 31 December 2005 (NO 2) exceeded > 18 times a year Annual mean 40 µg/m 3 (21 ppb) 31 December 2005 Particulate matter 24-hour mean 50 µg/m 3, not be exceeded 31 December 2004 less than 10 microns > 35 times a year in diameter (PM 10), Gravimetric* annual mean 40 µg/m 3 31 December 2004 Sulphur dioxide 15-minute mean 266 µg/m 3 (100 ppb), not to be 31 December 2005 (SO 2) exceeded > 35 times a year 1-hour mean 350 µg/m 3(132 ppb), not to be 31 December 2004 exceeded > 24 times a year 24-hour mean 125 µg/m 3 (47 ppb), not to be 31 December 2004 exceeded > 3 times a year
Provisional national objectives for air quality, for the protection of human health Benzene running annual mean 3.25 µg/m 3 (1 ppb) 31 December 2010 Carbon running 8-hour mean 10 mg/m 3 (8.6 ppm) 1 January 2005 monoxide (CO) Polycyclic annual mean 0.25 ng/m 3 31 December 2010 aromatic hydrocarbons (PAH) Particulate 24-hour mean 50 µg/m 3not to be exceeded 31 December 2010 matter less than > 10-14 times a year, 10 microns in for London diameter annual mean 23-25 µg/m 3, for London 31 December 2010 (PM 10), gravimetric* *Gravimetric refers to the method of measuring PM 10
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