Table 1.

Distribution across wards in decreases in average NOx concentration from 2001–2002 to 2003–2004 and in the proportion of admissions in 2001–2004 occurring in 2003–2004

	N	Mean (SD)	Percentile
			10th	25th	50th	75th	90th
Decrease in NOx (μg/m3)	Wards
Greater London	628	3.48 (1.90)	1.1	2.00	3.52	4.66	5.75
CCZ	39	5.81 (2.01)	3.11	4.51	5.73	7.27	8.52
Non-CCZ	589	3.32 (1.78)	1.04	1.93	3.33	4.50	5.50
Proportion of admissions in 2003–2004	Admissions*
Cardiovascular disease	206720	0.51 (0.05)	0.46	0.48	0.51	0.54	0.57
IHD	73892	0.51 (0.07)	0.42	0.46	0.50	0.55	0.60
Stroke	34882	0.50 (0.09)	0.39	0.44	0.50	0.55	0.61
Heart failure	27953	0.50 (0.11)	0.37	0.43	0.50	0.56	0.63
Respiratory disease	201033	0.54 (0.06)	0.48	0.50	0.53	0.56	0.60
COPD	39685	0.54 (0.10)	0.43	0.48	0.53	0.61	0.67
Asthma	32128	0.54 (0.10)	0.42	0.47	0.54	0.60	0.66
Bronchiolitis	8206	0.50 (0.18)	0.29	0.38	0.50	0.61	0.73

^*Column presents the number of hospital admissions according to disease group; however, the proportion of admissions occurring in 2003–2004 is distributed across 628 wards.

CCZ, congestion charging zone; COPD, chronic obstructive pulmonary disease; CVD, cardiovascular disease; IHD, ischaemic heart disease; NO_x, oxides of nitrogen.