Sampling pit and wall emission for H2S, NH3, CO2, PM, & odor from deep-pit pig finishing facilities

Air quality and emission measurements for ammonia (NH₃), hydrogen sulfide (H₂S), odor, and particulate matter (or dust) under 10 microns in diameter (PM₁₀) were collected from one room of a mechanically tunnel ventilated barn that contained two 1200 head capacity rooms located side by side (total capacity of 2400 finishing pigs) for approximately six months. Based upon similar magnitudes of ammonia and hydrogen sulfide concentrations measured in the center of the barn for all four; 0, 7, 17, and 34 m³/hr-pig (0, 4, 10, and 20 cfm/pig) pit ventilation cases used in the experiment, it can be concluded that "pit" ventilation has little effect on the barn's indoor air quality. The NH₃ and H₂S emissions determined in this study show that a disproportionate mass of these two gases were exhausted from the barn through pit fans when they were operating. This fact should be noted if a producer needs to reduce NH ₃, H₂S, and/or odor emissions, since there would be a benefit to treating only the pit fan exhaust air with an air emission control technology rather than all of the exhaust air (wall and pit). Finally the PM₁₀ concentrations and emissions from the pit fan air stream are lower than it is for the wall fans. The partitioning of the amount of airborne dust being emitted between the pit and wall fan airstreams has been unknown and is valuable for regulatory purposes and to assist in the design of emission control technologies that are used on either air stream.