B.C. Wolverton, PhD, president of Wolverton Environmental Services, Inc., an environmental consulting firm in Picayune, Mississippi. He previously spent more than 30 years working for the US military and the National Aeronautics and Space Administration (NASA) as a civilian scientist developing systems to protect against toxic chemicals and pathogenic microbes. He is author of Plants: Why You Can’t Live Without Themand How to Grow Fresh Air. WolvertonEnvironmental.com.