"October 1980."

I. Introduction -- II. Summary and conclusions -- III. Methods -- IV. Data analysis presentation The opacity of visible emissions from the two stationary sources with in the Mitchell Generating Stations, Northern Indiana Public Service Company (NIPSCO), Gary, Indiana, were measured during early morning and late afternoon hours on June 5, 1980. The sources investigated were Stacks I and II. All measurements were conducted remotely from off the plant site. Opacities were measured remotely with the NEIC Omega-1 Lidar which is a new instrumentation method. This method has been proposed in the Federal Register as Alternate Method 1 to Reference Method 9. Eight sets of opacity measurements were made, the total of which was about 2.25 hours of observation and about 830 individual measurements. The sets of measurements ranged in length from 15 to 30 minutes. Measurements were made at a temporal frequency range from once about every 9 to 11 seconds. All opacity measurements were subsequently analyzed and reduced with the NEIC laboratory computer using the methods given in Alternate Method 1 (proposed).