An emission inventory of agricultural internal combustion engines for California`s San Joaquin Valley

Previous work concluded that stationary agricultural internal combustion (IC) engines are a substantial source of criteria pollutants the San Joaquin Valley (SJV). However, due to time and resource restrictions, earlier work did not include a rigorous survey of engine users. Instead, emission estimates were based on interviews with a few knowledgeable experts (e.g., Department of Agricultural Engineering at U.C. Davis, the Agriculture Extension office of U.C. Davis, Farm Bureau, and Water District offices) or were extrapolated from data designed for other purposes. The purpose of the current study, which was sponsored by the San Joaquin Valley Unified Air Pollution Control District, was to improve the estimate of emissions from this source category by conducting a more comprehensive inventory of this source type based on data collected via a telephone survey of engine users. These survey data were then used to estimate and seasonally allocate emissions for this source category. The findings of this current work show that these emissions are much lower than previously estimated.