ANN ARBOR—R. Clay Porter, University of Michigan professor emeritus of mechanical engineering, died Dec. 14 in San Jose, Calif. He was 94 years old.

A pioneer in air-pollution studies for power plant and industrial smoke stack emissions, Porter’s work influenced stack design and plant siting throughout the United States and Canada.

Porter spent 36 years at the U-M, first as a graduate student in mechanical engineering and then as a member of the faculty. He began teaching at U-M as an instructor in 1937, and was promoted to assistant professor in 1940, to associate professor in 1943 and to professor in 1949. He retired from the faculty in 1973.

Porter was a registered Professional Engineer in Michigan and served the State Board of Registration as an examiner for 20 years. He was a regular and active participant at the American Power Conference in 1950-70. In 1968, Porter was elected as a Fellow in the American Society of Mechanical Engineers. He also was a member and faculty adviser to Tau Beta Pi, the leading Engineering Honorary Society, for 12 years. At his retirement, the R. Clay Porter Award was created by the society and has since been awarded to eight faculty and staff members.

Porter received his B.S. degree in engineering from the University of Kentucky in 1925 and his master’s degree in 1935. He received his M.S. degree from the U-M in 1938.

A member of Ann Arbor’s First United Methodist Church, Porter moved to California in 1973. He is survived by his wife, Isabel, of San Jose, Calif.; two sons, Stephen and Richard, and one granddaughter, Jessica. Memorial services have already taken place.