In memory of GLEN R. CASS (1947-2001)


Publications of Glen R. Cass

Air Pollution Expert Dies

Distinguished atmospheric scientist, Glen R. Cass, a professor of environmental engineering and mechanical engineering at the California Institute of Technology, died of cancer July 30, 2001 at Duke University Hospital in North Carolina. He was 54.

Cass, who received his Ph.D. from Caltech in 1978, taught at the Institute for 24 years. In January 2000 he joined the faculty of the Georgia Institute of Technology as chair of the earth and atmospheric sciences department. He maintained a joint appointment with Caltech.

Cass made a name for himself by painstakingly sleuthing out the myriad sources of air pollution that plague Los Angeles, beginning in the 1980s. Cass and his group ultimately generated a comprehensive database of source-emitted and ambient aerosol particles "that is without peer," says John Seinfeld, who holds the Louis E. Nohl Professor chair at Caltech's chemical engineering department. Christine Sloan remembers Cass making measurements everywhere possible, even inside fast food restaurants. "He knew the difference between whether the food was fried or grilled, and even what kind of oil they used," she says.

The long series of papers that resulted from this ongoing study "constitutes the definitive body of work on the chemical composition of organic aerosols," Seinfeld says. "His analytical chemistry was so meticulous that Glen was able to find traces of nicotine and cholesterol in atmospheric particles, markers for cigarette smoking and meat cooking in the ambient atmosphere. This body of work is of inestimable importance to air pollution research."

Glen Cass's research group has taken airborne particle measurements in many parts of the world, including India, the Maldive Islands, Cyprus, Poland, and parts of mainland China. Five sites in Beijing, China were monitored for "Operation Blue Sky," which identified pollution sources in Beijing, and whose results factored into China's 2008 Olympic bid. He also initiated a global ozone study at 400 sites around the world in 1999, which continues today.

A prolific scientist with more than 200 published articles, conference proceedings, book chapters, and technical reports to his credit, Cass's research focused on air pollution, with a particular emphasis on the control of airborne particles, photochemical oxidants, and improved visibility. He was instrumental in identifying the complex mix of airborne chemicals that pollute urban areas like Los Angeles and the Northeastern United States. Of special concern were very fine particles that can be inhaled and stay in the lungs, and that contribute to haze and poor visibility.  He once described haze as a "problem of worldwide note and local disgust."

Cass was equally interested in the protection of museum collections and archaeological sites from damage due to air pollution.  He and colleagues modeled air quality both within and just outside several museums throughout Southern California, which was useful in evaluating the effectiveness of various measures to protect works of art.

He did extensive research projects for the Getty Conservation Institute, including studies to determine which artists' colorants are subject to fading by gaseous pollutants like ozone, as well as many studies to determine air pollutant intrusion into museums and other facilities that house artwork, such as the new Getty Center in Los Angeles.

In China, he helped design computer-based models that simulated the air flow into the Yungang Grottoes, a collection of man-made cave temples dating from the 5th century A.D. that hold more than 50,000 stone carvings. The grottoes are situated in the middle of one of China's largest coal-mining regions. Cass's work contributed to the design of particle filtration systems and appropriate ventilation rates for reducing air pollution within the grottoes.

And in Poland, that country's monarchs had for centuries enhanced their wealth by trading in salt extracted from the huge Wieliczka mine. Over centuries mine workers were encouraged to decorate the mine's interior. The resulting freestanding statues, bas-relief carvings, and immense chandeliers - all carved from salt - have gained worldwide artistic and cultural renown. In the last century, however, the earliest and some of the most valuable of the carvings have melted into featureless blobs, thanks to pollution. Cass's work contributed to the finding that lowering the relative humidity in the mine would protect the salt from further deterioration.

Cass was a member of the U.S. Environmental Protection Agency's advisory committee on Ozone, Particulate Matter and Regional Haze Implementation Programs and formerly served on the EPA's Clean Air Scientific Advisory Committee.  He served on the editorial boards of the journals Aerosol Science and Technology, Environmental Science and Technology and served as a member of the research advisory committee and editorial board of the Health Effects Institute.

His sponsored research included work for the Environmental Protection Agency, the California Air Resources Board, NASA, the Department of Defense, Exxon, and the Ford Foundation.

He obtained a patent for systems reducing the deposition of fluid-borne particles.

He served on advisory panels for the National Research Council, the Lovelace Respiratory Research Institute, the Center on Environmental Health Sciences at MIT, the Universities Corporation for Atmospheric Research, and the South Coast Air Quality Management District.

Cass's wife, Jeanie, and son, Rob, were with him at the time of his death.  Cass will be cremated and his ashes taken to Maine, where the family has a home, to be scattered over the ocean.

Ph.D. students of Glen Cass:

Postdocs of Glen Cass:

Also see the group write-up from Prakash Bhave in his thesis appendix.

Additional Links:

Lynn Garry Salmon <>{

Last updated: January 4, 2021