SAN FRANCISCO – Portland, Ore., is the big city doing the best job of making its resources sustainable for future generations to enjoy without passing on a major cost burden, a new study says, according to MarketWatch. Portland ranked highest among the 50 largest U.S. cities for using its assets and infrastructure wisely, keeping money in the local economy and being prepared for the unexpected, according to a study from SustainLane.com, a nonpartisan online community site for healthy, sustainable living that’s based in San Francisco. San Francisco came in second this year, with Seattle taking third place. SustainLane’s 2005 survey evaluated only 25 cities and used different criteria. The 2006 report measures the 50 most populous cities based on 15 economic and quality-of-life categories. Cities were judged on their ability to maintain air quality and healthy drinking water, their use of renewable energy and alternative fuels, access to public transit, number of parks, green building, and local food production. The study looked for strong local economies that could handle sudden, unpredictable events such as surging energy prices and natural disasters, as well as the presence of easily walkable neighborhoods and downtowns, farmers’ markets, and affordable housing. Northwestern cities tend to do well in ecological studies, but East Coast and Midwestern hubs — such as Boston, Chicago, and New York — also made the top 10, the report said. Here are the top cities (of the 50 biggest cities) based on sustainability, according to SustainLane.com/:

1. Portland, Ore.
2. San Francisco
3. Seattle
4. Philadelphia
5. Chicago
6. Oakland, Calif.
7. New York
8. Boston