Table 1

Air pollution in Westminster

UK National Air Quality Strategy targets used in this studyUK targetBaseline levels in Westminster
1: Annual mean PM10 30.8 μg/m3[TEOM](40 μg/m3[gravimetric])UK target for 31.12.2004 Annual mean PM10
2: Annual mean PM10 15.4 μg/m3[TEOM](20 μg/m3[gravimetric])UK target for 31.12.200936 μg/m3 in 199638 μg/m3 in 199731 μg/m3 in 1998
3: 24 hour mean PM10 38.5 μg/m3[TEOM](50 μg/m3[gravimetric]), ⩽35 exceedencesrevised UK target for 31.12.200424 hr mean PM10 of 38.5 μg/m3[TEOM](50 μg/m3[gravimetric]), exceeded:
4: 24 hour mean PM10 38.5 μg/m3[TEOM](50 μg/m3[gravimetric])⩽7 exceedencesproposed UK target for 31.12.2009114 times in 1996130 times in 199767 times in 1998
I: Annual mean nitrogen dioxide 40 μg/m3(21 ppb),target for 31.12.2005Annual mean nitrogen dioxide 43 ppb in 1996 42 ppb in 1997 43 ppb in 1998
II: Hourly mean nitrogen dioxide 286 μg/m3(150 ppb)original UK National Air Quality Strategy target for 31.12.2005No of hours >150 ppb 5 in 1996 0 in 1997 0 in 1998
III: Hourly mean nitrogen dioxide 200 μg/m3(105 ppb), ⩽18 exceedencestarget for 31.12.2005 in revised strategyNo of hours >105 ppb 32 in 1996 30 in 1997 2 in 1998