Brownfield or brown field most often refers to Brownfield land, land formerly used as an industrial site.

Urban brownfields in Europe
Greenfields, Brownfields and Housing Development
Greenfields, Brownfields and Housing Development
Turning brownfields into green space in the City of Toronto
Quality data show the way to brownfields redevelopment
The Impact of Small Brownfields and Greenspaces on Residential Property Values
Brownfields and Greenfields: The Intersection of Sustainable Development and Environmental Stewardship
Urban brownfields as temporary habitats: driving forces for the diversity of phytophagous insects
Brownfields Redevelopment, Preferences and Public Involvement: A Case Study of an Ethnically Mixed Neighborhood.
Creative intervention in a dynamic city: A sustainability assessment of an interim use strategy for brownfields in Leipzig, Germany