He has served on various scientific advisory, editorial, and oversight panels, boards, and committees, including U.S. EPA Science Advisory Board and chair of the U.S. EPA Advisory Council on Clean Air Compliance Analysis. He has also been the recipient of honors and awards including: Thomas T. Mercer Joint Prize from the American Association for Aerosol Research and the International Society for Aerosols in Medicine (2001); Utah Governor's Medal for Science & Technology (2004); BYU Distinguished Faculty Lecturer Award (2006); and Gardner Prize, Utah Academy of Sciences, Arts, and Letters (2014).