Biofilter, Ventilation, and Bedding Effects on Air Quality in Swine Confinement Systems

This study evaluated housing designs and bedding systems to improve air quality in swine facilities, focusing on odor and particulate matter (PM) reduction. Three experimental animal house designs (M1, M2, M3) were tested: M1 used circulating airflow with negative pressure, M2 featured a plug flow air pattern with a perforated plastic bed, and M3 employed a sawdust bedding system with recirculating ventilation. Nine fattening swine were housed in each 12 m2 house over 110 days (6 May to 26 August 2018). Appropriate air samples were collected, and odorous compounds, volatile organic acids (VOA), PM, and bacterial concentrations measured. Results showed that M3 had the lowest ammonia (NH3) levels (5.9 ± 1.5 ppm) and undetectable hydrogen sulfide (H2S), while M1 recorded the highest NH3 (9.1 ± 2.2 ppm). VOA concentrations were significantly lower in M3 (75 ± 1.3 ppbv) compared to M1 (884 ± 15 ppbv) and M2 (605 ± 10.3 ppbv). PM10 levels were highest in M3 (312 ± 11 μg/m3) and lowest in M1 (115 ± 3 μg/m3), and thus bacterial counts were elevated in M3 (2117 ± 411 cfu/min), whereas M1 showed the lowest bacterial count of 1029 ± 297 cfu/min. The sawdust bedding system effectively reduced odorous compounds, highlighting its potential for odor control. However, higher PM levels in M3 emphasize the need to balance environmental management with animal welfare. These findings suggest that optimizing housing designs and bedding systems can enhance air quality in swine facilities while addressing sustainability and welfare concerns.