The control of gases inside pig production facilities is important to the pork production industry and the occupational health of workers in the pork industry. The overall goal of this study was to evaluate the air quality differences between deep pit and shallow pit swine finishing buildings with regard to NH 3 and H 2S concentrations while simultaneously evaluating the influence of various practices and building characteristics controlled by management on these concentrations. Four sampling visits were made to each of 26 swine finishing buildings over 15 months, beginning June, 2000, and continuing through August, 2001. Basic variable descriptions, summaries of NH 3 and H 2S concentrations, summaries of management variables, RH and temperature, and the associated descriptive statistics of variables including means, standard deviations, minimums and maximums were estimated. Tobit regression analyses were used to relate management practices and environmental variables to NH 3 and H 2S concentrations. Factors important in explaining variability in NH 3 concentrations included season, ambient temperature, sample collection site, and manure depth. Factors important in explaining variability in H 2S concentrations included season, feed type, sample collection site, pig space, and manure depth. H 2S concentrations were seen to decline with use of pelleted feed. Our results suggest that pelleted feeding is a more cost effective strategy than weekly flushing for H 2S control. The cost effectiveness of weekly flushing compared with biweekly flushing for NH 3 control was 0.25 ppm per dollar per marketed hog. Our analysis demonstrates benefits of building components and management tasks, and how to evaluate benefits against costs of the strategy.