Plume Diffusion in a Residential Neighborhood during Stable Conditions

摘要

As part of the EPA Integrated Air Cancer Program, a series of atmospheric tracer releases was conducted to investigate plume dispersion under wintertime, nighttime conditions in an urban valley as a basis for determining the relative impact of nearby and far away sources upon air quality monitoring sites. Hourly averaged diffusion rates exceeded typical rural diffusion rates by more than two stability classes and the McElroy-Pooler urban diffusion curves by one stability class. Horizontal diffusion rates estimated from turbulence data measured at the source agreed within 38 percent of the observed diffusion rates over distances of less than 1 km.