TY - JOUR T1 - U.S. discussion on air pollution raises questions for Canada JF - Canadian Medical Association Journal JO - CMAJ SP - 335 LP - 335 VL - 110 IS - 3 AU - D. V. Bates Y1 - 1974/02/02 UR - http://www.cmaj.ca/content/110/3/335.abstract ER -