This report documents the final year of a three year study of haze formation. The report is primarily concerned with the analysis of field data collected in previous years. computer programs in time-series analysis were used to develop empirical models relating hourly light scattering averages to other air quality and meteorological data. The models, constructed from a continuous period of aerometric data in New York City, contain CO, NO2, relative humidity, and total hydrocarbons as predictor variables. The models have been successfully applied to quantitatively predict light scattering in other regions.