Colorado State University Atmospheric Chemistry Professor Contributor to National Academies Report on Air Pollution

Note to Reporters: A photo of Professor Sonia Kreidenweis can be found with the news release at

Sonia Kreidenweis, professor in Colorado State University’s internationally recognized Atmospheric Science department, was one of only 15 U.S. researchers asked to contribute to a National Academy of Sciences report on the Significance of International Transport of Air Pollutants.

The committee issued a report in September 2009 that plumes of harmful air pollutants can have a negative impact on air quality far from their original sources. The scientists recommend that the United States, working in tandem with the international community, begin tracking and modeling sources of air pollution to develop appropriate solutions.

The report looks at four air pollutants: ozone; particulate matter such as dust, sulfates, or soot; mercury; and persistent organic pollutants such as DDT.

Kreidenweis served as lead author for the chapter focused on sources of and effects related to the long-range transport of particulate matter. At Colorado State, she studies the nature and behavior of particulate matter in the atmosphere and its effects on climate and visibility. Her group conducts laboratory and field measurements to clarify the relationships between particles and haze and cloud formation, which in turn can affect air quality and precipitation. Most recently, they have been focusing on characterization of particles produced from wild and prescribed fires, and have developed new recommendations for how smoke particle optical and cloud-forming properties should be represented in air quality and climate models.

“One of our key findings in the report was that ample evidence from satellite, ground-based, and aircraft observations now exists to show that particulate matter can undergo long-range transport to and from the United States across large ocean regions, and can even be readily detected in Colorado in extreme events, such as dust storms and large wildfires,” Kreidenweis said. “However, it is still difficult to estimate how much transported particulate matter reaches the surface to impact human health. The committee recommended improving and applying new methods for quantifying particulate matter transport – including increased use of space-based observations – to help fill these current information gaps.”

"Air pollution does not recognize national borders; the atmosphere connects distant regions of our planet," said Charles Kolb, chair of the committee that wrote the report and president and chief executive officer of Aerodyne Research Inc., in the National Academies news release. "Emissions within any one country can affect human and ecosystem health in countries far downwind. While it is difficult to quantify these influences, in some cases the impacts are significant from regulatory and public health perspectives."

Kreidenweis joined the CSU Department of Atmospheric Science in 1991 to initiate and direct the Atmospheric Chemistry program. The program offers a range of introductory and advanced courses in atmospheric chemistry, aerosol physics, and air pollution.