Atmospheric dispersion and transport within coastal regions—part I. Tracer study of power plant emissions from the Oxnard Plain

Abstract

Atmospheric tracer studies were conducted using the Ormond Beach Generating Station in Ventura County during September 21 and 22, 1975. The purpose of this work was to probe the transport and dispersion of atmospheric pollutants between Ventura and Los Angeles counties. The area of interest is characterized by rough terrain and complex, coastal meteorological conditions. The sulfur hexafluoride tracer data clearly show that pollutant transport occurs from the Oxnard Plain along the Malibu coast across the Lennox area into the San Fernando Valley of the Los Angeles Basin, and along an inland route through the Thousand Oaks area into the San Fernando Valley as far east as Reseda. These tracer data were found to be consistent with air parcel trajectories constructed from available meteorological data. Pollutants emitted from the Ormond Beach Generating Station, under the test conditions, were determined to be diluted by approximately 10 5 upon reaching the San Fernando Valley and upon reaching the Los Angeles Basin. Calculations using the Gaussian plume model yielded a close fit to the tracer data when values of the dispersion terms σ y , and σ z , were taken from the experimental results. Close agreement between the tracer data and the model predictions was also obtained using values of σ y , and σ z , from the Pasquill-Gifford atmospheric stability class which was one class less stable than that suggested to exist by wind speed and insolation measurements.