Seasonal differences in levels of carbon dioxide and ammonia in broiler housing

Abstract

Air emission and air quality issues are the important topics of environment in concern to poultry houses. This study attempts to point out possible sources of carbon dioxide and ammonia inside a broiler house, as well as an influence of several variables (temperature, age of chickens, ventilation rate) on their production. Concentrations and emissions of both gases (CO2 , NH3 ) were assessed over a total of six fattening periods from commercial tunel-ventilated grow-out facility designed for 25,000 broilers placed onto straw litter. CO2 production from heaters (approx. 39 kg/h) and CO2 production from bird respiration (approx. 147 kg/h) were compared with a total CO2 emission from the building ranging between 120 and 459 kg/h. CO2 emission was mostly affected by chickens towards the end of fattening period (P<0.001) taking dominance over natural gas burning process by heaters. Very high statistic reliability was found between age of chickens and NH3 concentration as well as between age of chickens and NH3 emissions (P<0.001). From seasonal point of view, there was not statistically significant difference in emissions of NH3 or CO2 between fattening periods (seasons). After the evalutation of carbon dioxide and ammonia emission, it can be concluded that there is an average releasing of 10.4 kg CO2 and 6.18 g NH3 per bird and period and/or 73.11 kg CO2 and 0.043 kg NH3 per bird yearly. Ammonia levels did not achieve critical values (≥20 ppm) many times during monitoring unlike carbon dioxide with peaks even tree times higher than it is allowed (≥3000 ppm). For that reason, not only the temperature but also the amount of air released from poultry buildings and the content of that air should be new variables in operating ventilation system.