Vernon Gordon MacKenzie, 75, a retired assistant surgeon general in the Public Health Service and a former chief of its air pollution division, died of cardiopulmonary failure July 4 at the National Community Hospital in Naples, Fla.

Mr. MacKenzie was born in Quincy, Mass., and graduated from the Massachusetts Institute of Technology. He also studied at the Harvard business school.

He joined the Public Health Service in Cincinnati in 1938. During World War II, he worked in Washington and then returned to Cincinnati, where he worked on problems of pollution. About 1951, he returned here and remained with the PHS until his retirement in 1968.

Mr. MacKenzie was the first chief of the division of air pollution in the PHS and worked for the major programs in this field that the government began adopting in the 1960s. He later was director of legislation for consumer protection in the Environmental Health Service at PHS. He retired from that position with the rank of rear admiral in the service.

In 1964, he received the PHS Distinguished Service Medal.

Mr. MacKenzie moved to Sanibel, Fla., when he retired and became vice mayor of that city. He later moved to Naples.

Survivors include his wife, Alice R., of Naples, two sons, Robert D., of Cincinnati, and Donald B., of Trafford, Pa.; nine grandchildren, and two great-grandchildren.