October 23, 1978 to November 19, 1978
Project Description: 

In recent years, a serious problem of acidic precipitation has become apparent in the eastern United States and other regions of the world. Though the chemical composition and pH of precipitation has been measured frequently, the actual acidic and basic constituents of the air itself have hardly been explored in a way designed to shed light on their control of precipitation acidity. The Acid Precipitation Experiment (APEX) is a project designed to explore the air chemistry underlying the acid preciptiation on a regional basis.

This was the first of several APEX missions to be flown. Samples of NO, NOx, O3, H2O2, H2SO4, and cloud/rainwater were taken. From RAF standpoint, the experiment went well.