EPA 231K13001 June 2013 www.epa.gov/smartgrowth Our Built and Natural Environments: A Technical Review of the Interactions Among Land Use, Transportation, and Environmental Quality SECOND EDITION Office of Sustainable Communities Smart Growth Program Acknowledgments The U.S. Environmental Protection Agency (EPA), through its Office of Sustainable Communities managed the preparation of this report. This report has been subjected to the Agency’s peer and administrative review and has been approved for publication as an EPA document. Mention of trade names or commercial products does not constitute endorsement or recommendation for use. Principal author: Melissa G. Kramer, Ph.D. Contributors and reviewers from the U.S. Environmental Protection Agency: • Office of Sustainable Communities: Danielle Arigoni, Ted Cochin, John Frece, Susan Gitlin, Jeff Jamawat, Adam Klinger, Megan McConville, Kevin Nelson, Kevin Ramsey, Megan Susman, John Thomas, Tim Torma, Brett Van Akkeren, and Beth Zgoda • Office of Air and Radiation: Ken Adler, Stacy Angel, Chad Bailey, Laura Berry, Gregory Brunner, James Hemby, Rudy Kapichak, Jean Lupinacci, Neelam Patel, Meg Patulski, Karl Pepple, Tamara Saltman, Erika Sasser, Kimber Scavo, and Mark Simons • Office of Chemical Safety and Pollution Prevention: Matt Bogoshian, David Sarokin, and Tom Simons • Office of Environmental Justice: Suzi Ruhl • Office of Policy: Alex Barron • Office of Research and Development: Fran Kremer, Melissa McCullough, Joseph McDonald, and Barbara Walton • Office of Solid Waste and Emergency Response: Ksenija Janjic and Patricia Overmeyer • Office of Water: Laura Bachle, Veronica Blette, Robert Goo, Rachel Herbert, Christopher Kloss, and Jennifer Linn • Region 5, Land and Chemicals Division: Bradley Grams Other federal government reviewers: • Centers for Disease Control and Prevention: Lorraine Backer, Ginger Chew, Daneen Farrow-Collier, Robynn Leidig, Erin Sauber-Schatz, Arthur Wendel, and Margalit Younger • U.S. Department of Transportation: Alexandra Tyson • General Services Administration: Ken Sandler • National Oceanic and Atmospheric Administration: Sarah van der Schalie External peer reviewers: • Alexander Felson, Yale University • Daniel Rodriguez, University of North Carolina • Susan Handy, University of California Davis • Frank Southworth, Georgia Institute of • John Jacob, Texas A&M University Technology • Kevin Krizek, University of Colorado • Paul Sutton, University of Denver • Dowell Myers, University of Southern California Cover photo credits: • Front cover, top left: drouu via stock.xchng • Front cover, top right: Kyle Gradinger via flickr.com • Back cover, top right: Dan Burden via Pedestrian and Bicycle Information Center • All others: EPA Table of Contents Executive Summary ....................................................................................................................................... i Chapter 1. Introduction ......................................................................................................................... 1 1.1 Purpose ........................................................................................................................................ 1 1.2 The Effects of the Built Environment on Human Health and the Natural Environment .............. 2 1.2.1 Direct Effects ........................................................................................................................ 2 1.2.2 Indirect Effects ..................................................................................................................... 3 1.3 Overview of Document ................................................................................................................ 3 Chapter 2. Status of and Trends in Land Use, Buildings, and Travel Behavior ...................................... 5 2.1 Status of and Trends in Population and Developed Land ............................................................ 6 2.1.1 Population ............................................................................................................................ 6 2.1.2 Metropolitan Area Size ........................................................................................................ 7 2.1.3 Developed Land ................................................................................................................. 10 2.2 Status of and Trends in Buildings ............................................................................................... 12 2.2.1 Housing Units ..................................................................................................................... 12 2.2.2 Building Energy Use ........................................................................................................... 14 2.2.3 Building Water Use ............................................................................................................ 16 2.2.4 Building Construction Waste Production ........................................................................... 19 2.3 Status of and Trends in Infrastructure ....................................................................................... 20 2.3.1 Roads ................................................................................................................................. 20 2.3.2 Parking ............................................................................................................................... 21 2.3.3 Water, Wastewater, Utilities, and Other Infrastructure .................................................... 22 2.4 Status of and Trends in Impervious Cover ................................................................................. 23 2.5 Status of and Trends in Travel Behavior .................................................................................... 25 2.5.1 Vehicle Travel ..................................................................................................................... 26 2.5.2 Induced Travel ................................................................................................................... 27 2.5.3 Transit, Walking, and Bicycling .......................................................................................... 29 2.6 Future Trends ............................................................................................................................ 31 2.6.1 Projected Population Growth ............................................................................................ 31 2.6.2 Projected Land Conversion ................................................................................................ 32 2.6.3 Projected Changes in Development Trends ....................................................................... 32 2.7 Summary .................................................................................................................................... 33 Chapter 3. Environmental Consequences of Trends in Land Use, Buildings, and Vehicle Travel ........ 34 3.1 Habitat Loss, Degradation, and Fragmentation ......................................................................... 34 3.1.1 Effects of Habitat Loss ........................................................................................................ 35 3.1.2 Effects of Habitat Degradation .......................................................................................... 38 3.1.3 Effects of Habitat Fragmentation ....................................................................................... 41 3.1.4 Effects of Roads: Combined Effects of Habitat Loss, Degradation, and Fragmentation .... 43 3.2 Land Contamination .................................................................................................................. 44 3.3 Degradation and Loss of Water Resources ................................................................................ 46 3.3.1 Effects of Development on Stream Hydrology .................................................................. 48 3.3.2 Effects of Development on Stream Geomorphology ......................................................... 49 3.3.3 Effects of Development on Water Pollution and Nutrients ............................................... 51 3.3.4 Effects of Development on Aquatic Life ............................................................................ 54 3.3.5 Levels of Development at Which Effects Are Apparent ..................................................... 55 3.3.6 Loss of Water Resources .................................................................................................... 56 3.4 Degradation of Air Quality ......................................................................................................... 57 3.4.1 Criteria Air Pollutants ......................................................................................................... 57 3.4.2 Air Toxics ............................................................................................................................ 59 3.4.3 Human Health and Environmental Effects of Air Pollution ................................................ 60 3.4.4 Indoor Sources of Pollution ............................................................................................... 61 3.5 Heat Island Effect ....................................................................................................................... 65 3.6 Greenhouse Gas Emissions and Global Climate Change ...........................................................