Earlier this year, Popular Science ranked America's 50 Greenest Cities, coast to coast. Using raw data from the U.S. Census Bureau and the National Geographic Society, Popular Science assigned scores of up to 5 or 10 points in four general categories: Electricity, Transportation, Green Living, and Recycling and Green Perspective.

The cities were then ranked 1-50 based on their cumulative score. San Francisco was again found to be near the top – 2nd place actually, with 23/30 points. Just behind 1st-place Portland, Oregon, which scored a 23.1.

Looking around the city, you’ll find S.F. integrating both new and established green practices daily. Perhaps – just maybe – by next year’s survey, we will have made up that one-tenth of a point. That’s the goal! As for the more immediate future however, did you know/remember that Earth Day is only a few days away (April 22)?

The beautiful weather in San Francisco and the city’s relatively small size, both beckon one to get outdoors and explore. At this time of year, you’ll find sidewalks filled with outdoor seating. Open spaces never empty. The water dotted with watercraft and fun. Speaking of which, how does a free concert sound?

Beginning this weekend, in celebration of Earth Day, S.F. will be partaking in the 3rd Annual Green Apple Festival, April 18-20. Hosting art and music events all weekend-long, the city will cap it all off with an eco-friendly, free concert in Golden Gate Park. Should you attend, do your part by taking public transportation and/or walking to any of the participating venues. Keep in mind the size of your carbon footprint, which can indeed be curbed even while on vacation.

For more ideas on how to get involved with Earth Day this year, check out what About.com’s Guide to Adventure Travel Lois Freidland has gathered. She offers a comprehensive look at how you can help promote environmental awareness in your travels, from what you do to where you go to how you get there. Thanks for the ideas, Lois!

And have a great Earth Day, everyone. :)

^{* Golden Gate Bridge from Baker Beach. Photo © Justin Sullivan/Getty Images.}