This paper will attempt to point out the perplexity of the outdoor odor pollution problem and the difficulty encountered by the official in dealing with industry and the public in this matter. The odor situation is not so difficult to handle when the source is a well-defined continuous process running day in and day out so that the odor pollution level rises in a particular neighborhood with a degree of regularity whenever the weather influences are right—that is, when a straight flowing air stream carries the pollutants in a well-defined fan-like directional pattern to the affected neighborhood downstream from the plant or when a stagnant air mass forms under a low level temperature inversion layer, causing the pollutants to mushroom over an entire area. However, when the offending source is a one- or two-batch process from among many or when different materials processed through the same equipment result in foul smelling discharges one time and perfumed fragrance another so that the odor emissions are spasmotic, catching or missing weather conditions to cause odor build-up without pattern or cyclic recurrences, it is harder to analyze the situation than to pick out the shell that covers the pea at the carnival. When process operators receive a call about an odor situation, they can change the process a little and then deny all responsibility for the odor source and defy the official to find out where it came from and what caused it. When an accusing finger is pointed to the plant as the source, the retort is, “Who, me? I don't smell anything.” Not all do this, but there are some plants that do. Local ordinances usually declare strong and obnoxious odors to be a nuisance and the emission of such odor to be unlawful. The wording of the Cincinnati Ordinance is quoted as follows: Section 2501-3(b).—Acid or other fumes, noxious gases, strong odors, dust, dirt, or other solids in quantities (defined in Section 2501-5) emitted or allowed to escape in such place or manner as to cause injury, annoyance or detriment to the public, or to any person or to endanger the health or safety of such a person or the public, or emitted in such a manner as to cause injury or damage to business or property, are hereby declared a nuisance, and the emission or escape thereof from any stack, or chimney, window, door or other opening, ventilating device, or from any building, premises or other source, shall be unlawful.