No use shall emit odorous gases or other odorous matter in such quantities as to be detectable at any point on or beyond its lot lines. The guide for determining such quantities of offensive odors shall be the 50% response level of Table I, Odor Thresholds in Air, Research on Chemical Odors: Part I, Odor Thresholds for Commercial Chemicals, October 1968, or most recent edition, Manufacturing Chemists Association, Inc., Washington, D.C.