Northern Arizona University has been listed in the Princeton Review’s Guide to 286 Green Colleges for demonstrating “an exemplary commitment to sustainability.”

The guide was released Tuesday in celebration of today’s 40th anniversary of Earth Day.

The Princeton Review cited the university’s three LEED-certified buildings in 2009—since then it has added a fourth—calling NAU a “green building superstar.” It also repeated the Chronicle of Higher Education’s naming of the Applied Research and Development building as the “greenest building in higher education.”

The publication also cited the university’s numerous initiatives to create a carbon-neutral campus by 2020.

To produce this guide Princeton Review partnered with the United States Green Building Council, a national nonprofit organization that promotes sustainability in the design and construction of buildings. The two organizations looked at an institution’s commitment to building certification using the council’s LEED green building certification program; environmental literacy programs; formal sustainability committees; use of renewable energy resources; and recycling and conservation programs.

To read details or download the free guide visit princetonreview.com/green-guide.aspx.