Book excerpt: Earth has a pollution problem. How can you help? Join Tyler to learn what makes Earth's land, air, and water dirty. Find out cool ways to clean up our world. Do your part to be a planet protector! Discover how to reduce, reuse, recycle, and more with Tyler and Trina in the Planet Protectors series, part of the Cloverleaf BooksTM collection. These nonfiction picture books feature kid-friendly text and illustrations to make learning fun!