A cross-sectional epidemiologic study associating air quality with swine health was conducted on 28 swine farms in southern Sweden. Correlation of housing air environment to swine diseases and productivity (data collected over the preceding 12 months) were investigated. The most prevalent swine health problems detected at slaughter were pneumonia and pleuritis. In farrowing and nursery operations, the most prevalent problem was neonatal pig mortality. Several air contaminants (dust, ammonia, carbon dioxide, and microbes) were found to be correlated with these swine health problems. Maximal safe concentrations of air contaminants were estimated on the basis of dose-response correlation to swine health or human health problems. Recommended maximal concentrations of contaminants were: dust, 2.4 mg/m3; ammonia, 7 ppm; endotoxin, 0.08 mg/m3; total microbes, 10(5) colony-forming units/m3; and carbon dioxide, 1,540 ppm. The overall quality of the ventilation system was correlated with lower concentration of ammonia, carbon dioxide, microorganisms, and endotoxin, but not with dust concentrations. High animal density was related to high ammonia and air microbe concentrations. Animal density measured as kilograms of swine per cubic meter (compared with kilograms of pig weight or swine per square meter) had the highest correlation to animal health and air contaminants.

Environmental variables in 10 commercial turkey confinement buildings, representing 2 natural ventilation designs, were measured during summer and the following winter. Sliding doors spaced at intervals along the walls of 5 of the buildings provided about 35% opening, and continuous wall curtains provided 60 to 80% opening in the other 5 buildings. Environmental variables assessed included airspeed; temperature; relative humidity; gases; particle number, size, and mass per cubic meter of air; and colonies of bacteria, yeasts, and other fungi per cubic meter of air. Colonies of yeasts and other fungi were quantitated in feed and litter. For most of the variables evaluated, significant differences were not attributable to building ventilation design; however, in winter, the total mass of particulate matter per cubic meter of air was higher in the curtain-type houses, compared with sliding door-type houses. Ammonia concentration in the air of sliding door-type houses progressively increased during summer and winter sampling periods. A significant effect of building ventilation design on turkey performance was not detected when using mortality, average daily gain, feed conversion, condemnations at slaughter, or average individual bird weight as measures of production.

Microbial quality of air in a dairy processing plant was evaluated to ascertain the contribution of air as a source of contamination and spoilage of milk and milk products. The mean total aerobic counts obtained in the air by sedimentation method were 32.66 ± 3.82, 25.32 ± 4.17 and 33.36 ± 3.53 cfu/m 2 in raw milk reception dock, pasteurization room and product preparation room respectively. The respective mean total coliform counts were 1.52 ± 0.14, 0.66 ± 0.08 and 0.99 ± 0.16 cfu/ m2. Total coliform count observed in the raw milk reception dock was significantly higher (P< 0.01) than the other areas.  The mean Staphylococcal counts were 2.52 ± 0.10, 3.84 ± 0.31and 5.82 ± 0.30 cfu/ m2. The product preparation room showed highest mean Staphylococcal counts followed by pasteurization room and raw milk reception dock.  The mean yeast and mould counts obtained were 5.42 ± 0.39, 3.84 ± 0.31and 5.82 ± 0.30 cfu/ m2  in raw milk reception dock, pasteurization room and product preparation room respectively. Effect of fumigation on the microbial quality of air in the dairy processing area was also studied by comparing the microbial load in the air before and after fumigation. Fumigation practice followed in the dairy processing area was highly effective against total aerobic organisms, coliforms, and Staphylococci but not very effective in the case of yeast and moulds.

Liquid manures stored produce a significant amount of methane (CH4) and ammonia (NH3) gas from biological anaerobic fermentation. Studies carried out to evaluate a potential biological cover on inhibiting gases emission and simple cover design to overcome the high cost of biogas production on covered lagoon types that are available on the market. The agriculture waste from rice straw, cocopeat, hay, and sawdust were used as biological covers in reducing CH4 emission and NH3 volatilisation from ruminant slurries. During ninety days of the undisturbed storage period, immediate reduction of CH4 and NH3 gases fluxes were observed after the application. Rice straw and coco peat were found to effectively reduce the emission of CH4 and NH3 between 45.5% and 56.9%. Other biological cover showed a slightly lower reduction on NH3 volatilisation and much lower in CH4 inhibition percentage (28-29%). Covering method was found to be suitable with Malaysia’s climate in reducing greenhouse gas emission from slurry manure.