Emissions of atmospheric pollutants from a combined commercial dairy barn

摘要

Animal agriculture has been trending toward larger scale farms to accommodate the need for animal products. The increase in farm size has created an increased waste stream of solids and gases. The goal of this study was to develop emission factors formethane (CH_4), ammonia (NH_3), and size fractionated particulate matter (PM_(10) and PM_(25)) from a dairy barn to address knowledge gaps in the Canadian agricultural emissions inventory. A heated sample line conveyed barn air into a trailer that housed a methane/non-methane hydrocarbon flame ionization detector (FID) to sample for CH_4 and an NH_3 chemiluminescence analyzer. The PM was sampled using an optical particle counter that was placed in the barn. Two sampling runs were conducted during the winter and the spring to compare the effect of seasonal changes. The winter results for NH_3, CH_4, PM_(25) and PM_(10) were 2.12, 29.0, 0.0011, 0.00037 g hr~(-1) ALT1 (AU- animal unit equivalent to 500 kg live mass), respectively. The spring results forNH_3, CH_4 were 1.82 & 11.6 g hr~(-1) AU~(-1) respectively, and for PM_(25) and PM_(10), 2.0 & 0.91 mg hr~(-1) AU~(-1), respectively. In the winter and spring, there are two significant spikes in emissions for CH4 and NH_3 occurring between 06:00 and 09:00 and 16:00 and 19:00. In the spring, the spikes are almost equal while, in the winter, the morning spike is much smaller than the afternoon. PM displayed similar seasonal patterns with one significant event at 08:00. There are many activities in the morning that could contribute to the first spike in emissions of all contaminants (e.g. lights turning on, feeding and manure belt activation), but the only major activity in the afternoon is feeding.