All three of the state’s schools ranked in the top 100 greenest universities, according to Sierra Magazine.

The University of Arizona is the highest of the three, coming in at 22.

Arizona State University sits at 55, and Northern Arizona University rounded out the state’s schools at 85.

The magazine, which is published by the Sierra Club, based the rating on issues, such as where the buildings get their power from: "coal, hydropower or wind?," said Avital Andrews Sierra Magazine’s lifestyle editor. “All the way down to, 'what are the napkins in your cafeteria made out of?Are they made from recycled materials or are they virgin paper?'"

Other factors weighing into the score include research done by a school on sustainability, transportation on campus, and energy use by buildings.

This is the sixth year of the survey, put on by the Sierra Club, the Association for the Advancement of Sustainability in Higher Education, the Sustainable Endowments Institute, and The Princeton Review.

The full list and each university’s individual reports is available at the Sierra Club’s website.