The fourth follow-up report on the 15 Air Pollution Pilot Study recommendations is to monitor the status of the adoption of NAC NATO/CCMS Recommendations I,II,III,IV,V,VII, and VIII in cities with population over 600,000 in 1978. The report also can be compared to the 1975, 1976, and 1977 survey responses and the first three follow-up reports to evaluate changes in air pollution activities in the past three years. The NAC NATO/CCMS recommendations listed above include general assessment of air pollution, standard-setting, establishment of air quality monitoring systems and suitable systems for retrieval and storage of data, employment of recognized reference methods for monitoring, and institution of uniform procedures for conduction emissions inventories.