RT Journal Article SR Electronic T1 Air pollution and poverty: Does the sword cut both ways? JF Journal of Epidemiology and Community Health JO J Epidemiol Community Health FD BMJ Publishing Group Ltd SP 2 OP 3 DO 10.1136/jech.58.1.2 VO 58 IS 1 A1 F W Lipfert YR 2004 UL http://jech.bmj.com/content/58/1/2.abstract AB