Make sustainable purchases that protect your local air and water quality. Get involved with local politics to bring sustainability to your area.

Could your town become as sustainable as San Francisco? It’s up to you.

RODALE NEWSROOM, EMMAUS, PA— Since 2002, the community web site SustainLane.com has been rating the 50 most populous U.S. cities on sustainability, that is, meeting today’s needs without messing up future generations’ ability to meet theirs. Portland, Oregon tops the SustainLane U.S. List of Rankings for the 2008 list, followed by San Francisco, Seattle, Chicago, New York, Boston, Minneapolis, Philadelphia, Oakland and Baltimore. Portland captured the top spot for its high marks in green building, air quality, and green city planning.

THE DETAILS: SustainLane CEO and president James Eisen says 50% of the ranking data consist of publicly available info from sources like the EPA, US Census, and Smart Growth, as well as other government and nongovernmental organizations. SustainLane collects the other half of the data through surveys, interviews, and information analysis. Their peer-reviewed work takes about a year to put together, Eisen says. The ranking takes into consideration air and tap-water quality, city commuting, energy and climate change, local food and agriculture, green building and economy, housing affordability, planning and land use, and several other factors.

While famously crunchy Portland took the top prize in many categories, others cities found their green niches, too. Chicago and San Francisco won points for looking to renewable energy and urban greening. Local food systems in places like Philadelphia, Boston, Minneapolis and Oakland are making it easy for people to get their hands on local, organic produce and grass-fed meats. Atlanta and Washington DC are leaders in green building, and Denver, Charlotte, Phoenix, and Dallas are developing citywide transportation. Columbus, Ohio, ranked as the most improved city, thanks in part to its $50 million investment for bike and pedestrian transportation improvements; earlier this year, Bicycling magazine named Columbus one of the top biking cities of the future.

WHAT IT MEANS: Not everyone can live in the cities on this list. But wherever you are, there are ways to bring sustainability to your community and preserve resources for future generations.