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Because of the Federal Clean Air Act Amendments of 1990, the San Joaquin Valley Unified Air Pollution Control District (SJVUAPCD) began defining Best Available Control Technology (BACT) for NOx emissions from cotton gin drying system gas-fired burners in its jurisdiction. The NOx emission levels of conventionally used, direct-fired burners were unknown, as was how direct-fired burners would compare against newer lo-NOx burners or against the proposed SJVUAPCD NOx emission standard of 60 ppm or less. Replicated laboratory studies were designed to determine the emissions and fuel efficiency of both direct-fired and lo-NOx burner designs. NOx emission levels during the test averaged from 3 ppm for one of the lo-NOx designs to 36 ppm for a direct-fired burner when tested over four firing rates. An economic analysis of the specific cost of NOx reduction achieved by substituting a lo-NOx burner for a direct-fired burner showed an annual capitalized cost of $13,945/tonne ($12,648/T) of NOx reduction. The SJVUAPCD has an upper limit of $10,670/tonne ($9700/T) of NOx reduction to qualify for definition as BACT. Using this economic criterion, lo-NOx burners do not meet the definition of BACT for cotton gins for the SJVUAPCD, and, based upon conferring with industry and environmental specialists, would not for the rest of the United States.

Three cotton varieties were grown under furrow-irrigated conditions in southern New Mexico and harvested with three different spindle picker machine/speed combinations. Results for harvest losses and trash content showed a highly significant interaction between variety and machine/speed combination. This interaction caused difficulty in interpreting results from this 1-year study. Therefore, a follow-up study is planned.

Three cotton varieties were grown under furrow-irrigated conditions in southern New Mexico and harvested with three different spindle picker machine/speed combinations. Results for harvest losses and trash content showed a highly significant interaction between variety and machine/speed combination. This interaction caused difficulty in interpreting results from this 1-year study. Therefore, a follow-up study is planned.

Simultaneous source testing and boundary line testing were conducted at an operating cotton gin in the San Joaquin Valley, California. Results of the simultaneous testing were compared regarding their indication of compliance with air pollution regulations and standards.