Table 2

Spearman correlations between ward-level reductions in NO_x and ward-level socio-demographic variables

Variable	Description	Δ Inc	IMD	Δ 65 years +	% NW	% Bl	% As	% Ch
Δ NO_x	Reductions in average NO_x from 2001–2002 to 2003–2004 in μg/m³	−0.21^*	0.27^*	0.13^*	0.03	0.14^*	−0.10	−0.02
Δ Inc	Change in proportion of residents living in income deprivation between 2001 and 2005		−0.21^*	−0.16^*	−0.34^*	−0.21^*	−0.42^*	0.23^*
IMD	Index of Multiple Deprivation in 2001 (higher values for more deprived wards)			0.26^*	0.61^*	0.78^*	0.18^*	0.13^*
Δ 65 years +	Change in population aged 65 years or older between 2001–2002 and 2003–2004				0.02	0.16^*	−0.07	−0.02
% NW	% Non-white residents					0.79^*	0.73^*	0.30^*
% Bl	% Black residents						0.29^*	0.18^*
% As	% Asian residents							0.25^*
% Ch	% Chinese residents