Impact of alternative air exhaustion in housing for poultry on concentration of harmful gases in the air

Abstract

The main aim of the paper is to assess an alternative way of disposal of pollutants from housing area, where the air is sucked from spaces below the animals. Measurements were taken in experimental conditions of enriched cage for 10 hens. Pipe for suction was located under the floor of the cage. Gas concentration was determined by the device 1412 Photoacoustic Multi-gas Monitor. Air samples were collected at the animal's head level. Air temperature was continuously registered by the device COMMETER D3120, and air velocity was measured by the anemometer ALMEMO 3290. Measurements were conducted for 6 consecutive days in each season of the year (spring, summer, autumn and winter). The obtained results were compared with the concentration of harmful gases obtained without the use of the exhausting device. Average values of harmful gases concentrations obtained with utilisation of air suction device placed under the floor of the cage were almost in all cases lower. According to season of the year they varied without air suction device in CO₂ 832.06 to 1000.75 mg.m^-3 versus 813.405 to 957.59 mg.m^-3 with the device exhausting air from the space under the floor. In N₂O it was 0.951 to 1.076 mg.m^-3 compared with 0.972 to 1.055 mg .m^-3, in NH₃ from 0.013 to 0.092 mg.m^-3 compared with 0.007 to 0.069 mg.m^-3, in H₂S from 0.171 to 0.579 mg.m^-3 compared with 0.17 to 0.436 mg.m^-3 and in CH₄ 2.076 to 7.211 mg.m^-3 compared with 1.516 to 5.018 mg.m^-3. Change of the way of housing ventilation significantly reduced the rate of air flow at the level of laying hens’ heads, too. In winter, it was on average 0.6 compared with 0.11 meters per second and in summer 1.2 compared with 0.15 meters per second. While the temperature at the level of birds’ heads was in winter season higher at the alternative way of ventilation, it had slightly opposite effect during the other seasons in this experiment. This would need additional research.