This article is a critical analysis of the following study: Martins MC, Fatigati FL, Vespoli TC, Martins LC, Pereira LA, Martins MA, Saldiva PH, Braga AL. Influence of socioeconomic conditions on adverse health effects of air pollution in elderly people: an analysis of six regions in São Paulo, Brazil. J Epidemiol Community Health. 2004 Jan;58(1):41-6. The objective of this study is to assess whether socioeconomic status modifies the effects of PM10 air pollution on respiratory mortality among the elderly. The results suggest that low socioeconomic status has a modifying effect on the association between air pollution and respiratory mortality. The authors propose to continue their study by analyzing causes of mortality in greater detail through a cohort study and by expanding the number of areas investigated. Beyond the limitations inherent in any ecological study, this work conducted among older adults helps reinforce the notion of a relationship between socioeconomic status and pollution-related respiratory mortality.