Buffers and Barriers
Buffers can reduce exposure using vegetative (e.g., trees, shrubs), distance, and/or physical barriers (e.g., sound walls) between pollution sources and homes, schools and other places where people may be exposed. Buffers reduce exposure by absorbing or blocking some of the pollution, thus lowering concentrations. Buffers can help to reduce concentrations of O3, PM, NOX, SO2, and CO,(1) especially at residences and schools near highways and industrial facilities. Initiatives underway in Detroit include a carbon buffers pilot program implemented by Detroit Future City and Greening of Detroit at a several sites; a green buffers plan to protect the Delray and portions of Southwest Detroit from industry and increased vehicle traffic from the future Gordie Howe International Bridge led by the Community Benefits Coalition and Detroiters Working for Environmental Justice; policy recommendations for planting trees developed the Healthier and Greener Detroit workgroup; and a noise abatement program for installation of sound walls by the Michigan Department of Transportation. Additional strategies include requiring minimum setbacks (150 meters or more from heavily trafficked roadways to residential areas, schools, health care facilities, senior centers and other sensitive land uses); expanding efforts to create vegetative buffers along major roadways, with particular attention to vulnerable populations; increasing tree canopy; creating policies that require buffers when new developments are implemented; requesting buffers as part of Community Benefits Agreements; and supporting partnerships between relevant organizations, such as Greening of Detroit and state and local authorities, to assure integration of buffer plans with other planning activities.
1. Nowak, DJ, Crane, DE, Stevens, JC. Air pollution removal by urban trees and shrubs in the United States. Urban Forestry and Urban Greening 4:115-123.