Neighborhood effects on health have been widely investigated; yet the definition of neighborhoods is usually arbitrary. This study analyses how disparities in environmental exposure according to urbanicity vary when considering a home-centered network-buffer, the perceived residential neighborhood, or the activity space. Exposures to the density of destinations and proportion of green space were compared for three spatial definitions of exposure areas, overall and stratified by urbanicity of the residence. Environmental exposure levels and gradients by urbanicity were found to vary depending on the spatial definition of the exposure area.