Multiple Impacts of the Built Environment on Public Health: Walkable Places and the Exposure to Air Pollution

While considerable attention has been paid to the public-health-related impacts of air pollution, relatively little research has been done to understand how other aspects of the built environment impact health. Americans are increasingly sedentary; erstwhile the rate of increase in obesity is alarming. New research suggests that increased auto dependence, and limited opportunities to walk for utilitarian purposes, has contributed to this emerging obesity epidemic. Within sociodemographic strata, land use patterns and transportation investments collectively shape the desire to walk, drive, or to travel via other means. Mixed use and more compact community designs show significant promise for the promotion of physical activity and the reduction of regional air pollution levels. Opportunities exist to increase physical activity and improve regional air quality through more compact development. However, increased compactness, or density, often exacerbates traffic congestion and can increase exposure of harmful emissions within central areas. Therefore, strategies to reduce localized air pollution in existing and developing centers are required to enable larger health benefits from smart growth to be realized.