The air quality data analyzed in this report came from the National Air Pollution Surveillance monitoring network, consisting of air monitoring stations in most cities with populations of over 100,000. Monitoring is conducted for sulphur dioxide, nitrogen dioxide, carbon monoxide, ozone, suspended particulates, lead, and soiling index. This report analyzes monitoring data to determine national trends in average and peak concentrations of these contaminants on an annual basis for the last 10 years (1978-87). Data were also compared with the National Ambient Air Quality Objectives which define levels of contaminant concentration of maximum desirable, maximum acceptable, and maximum tolerable.