This paper reports the findings of a study of finance systems in nine air pollution control agencies for producing revenue. These revenue producing systems include various permit fees, inspection fees, monitoring/surveillance fees, and specially earmarked taxes. The agencies studied included two State agencies (Oregon and Wisconsin) and seven local agencies (St. Louis, Philadelphia, Chicago, New York, Los Angeles, San Francisco Bay Area, and Puget Sound). The study found that collecting fees usually presented few problems except where fees were levied against other public entities (e.g., schools, government buildings). It also concluded that fees alone are not major enforcement aids.