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Malm, William
CIRA Fellow

Dr. William Malm

Senior Research Scientist, CIRA, Colorado State University

Mailing Address:
Bill Malm
Cooperative Institute for Research in the Atmosphere
Colorado State University
1375 Campus Delivery
Fort Collins, CO 80523-1375
  • Office Location:
    CIRA Room 101
  • 970-491-8292
About Me:

Dr. William C Malm is a research scientist/scholar at Colorado State University’s Cooperative Institute for Research in the Atmosphere (CIRA) and a recently retired research physicist in the National Park Service Air Resources Division where he was program coordinator for the visibility/particulate research and monitoring program.  He received his B.S. degree in physics and a minor in mathematics from Mankato State University in 1965 and his M.S. and Ph.D. degrees in physics from the University of North Dakota (1968) and the University of Missouri (1972), respectively.  He has previously worked as an Environmental Protection Agency (EPA) research scientist and as a professor of environmental science at Northern Arizona University in Flagstaff.  He is a member of the Air & Waste Management Association (AWMA), the American Geophysical Union (AGU), and the American Association for Aerosol Research (AAAR).  He has served as an organizing chair for special sessions in each of these associations and as a guest editor for the Journal of Geophysical Research (JGR) and the Journal of the Air & Waste Management Association (JAWMA).  He is also a topic editor for environmental monitoring for the Encyclopedia of Earth.  He has received a number of awards for outstanding lectures and various research activities.  In 2009 he received the George Wright Society 2008 Director’s Award for Natural Resources, the EPA Thomas W. Zosel 2008 Outstanding Individual Achievement Award, and the Air & Waste Management Association’s Frank A. Chambers Excellence in Air Pollution Control Award for his research contributions in the areas of visibility and air quality.  He serves as a science advisor to the EPA as a member of the Clean Air Scientific Advisory Committee.


Dr. Malm’s expertise is in the general area of visibility and related topics.  He made some of the first visibility and air quality measurements in the National Park Service system at the Grand Canyon in 1972.  Since then he has designed and built instrumentation to measure the effects of atmospheric aerosols on the scenic qualities of landscape features, as well as their optical and chemical properties.  He has formulated radiation transfer algorithms that allow pictorial visualization of aerosol scattering and absorption effects on scenic landscape features.  He pioneered studies of visibility perception that elicit human responses, in terms of both psychophysical and value assessment, to changes in scenic quality as a function of aerosol optical properties.  He has initiated and carried out large field campaigns to better characterize aerosol physical and optical properties, especially as they relate to aerosol hygroscopic properties, and to assess the relative contributions of various source types to visibility impacts in a number of national parks and wilderness areas.  He has also pioneered a number of back-trajectory receptor modeling methodologies that allow estimates of the relative contributions of source areas to aerosol concentrations or visibility effects at selected receptor sites.  Many of the results from this work have been incorporated into the Interagency Monitoring of Protected Visual Environments (IMPROVE) program and the EPA Regional Haze Rule (RHR).