Toxic gas and respirable dust concentrations and emissions from broiler and cage-layer barns in the Canadian Prairies
2020
Huang, Dandan | Guo, Huiqing
This study monitored concentrations and emissions of ammonia (NH₃), hydrogen sulfide (H₂S), and respirable dust for a commercial broiler and a cage-layer barn in the Canadian Prairies over a year between March 2015 and February 2016. Seasonal concentration and emission profiles were acquired by monthly measurements, while diurnal profiles were generated in different seasons. The indoor air quality was evaluated considering both the individual and the additive health effect (respiratory irritation) of the three air pollutants. In winter, both 8-h and 15-min exposure limits (threshold concentrations) of NH₃ were exceeded in the broiler barn; the highest additive level was more than two times of the limit. Seasonal average emissions of NH₃, H₂S, and respirable dust were 57 g d⁻¹ AU⁻¹, 1.35 g d⁻¹ AU⁻¹, and 1.99 g d⁻¹ AU⁻¹, respectively, for the layer barn, all with higher levels in the mild and warm seasons than in the cold season. The emission data were only obtained for the worst-case scenarios (last week of the production cycle) of the broiler barn, with annual averages of 92 g d⁻¹ AU⁻¹ for NH₃, 1.19 g d⁻¹ AU⁻¹ for H₂S, and 4.32 g d⁻¹ AU⁻¹ for respirable dust, with obvious higher NH₃ levels in winter. Additionally, manure removal once every 3–4 days for the layer barn reduced NH₃ emissions by 62% and 90% in the cold and mild seasons, respectively. This study also found significant negative influence of outdoor T (Tₒᵤₜ) on NH₃ emissions for the broiler barn but positive impact of Tₒᵤₜ on NH₃ emissions for the layer barn.
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