Particulate Matter from an Egg Production: Emission, Chemistry, and Local Dispersion.

摘要

The environmental and possible health effects of air emissions from AFOs are a significant concern not only at the local scale in rural areas, but also at regional and global scales. However, limited scientific data on AFOs' emissions are available for particulate matter (PM) emission, chemistry and local dispersion. The effects of environmental factors and facility management practices on PM concentration and emission are important for developing mitigation technology and implementing regulations; however a knowledge gap remains to identify the key factors. Information of PM by mass only is not sufficient to provide a clear understanding of its environmental and health effects, fate and transport, comprehensive chemical composition analyses of PM are therefore needed.;This study was conducted in response to the lack of consistence AFO PM data in the literature, the lack of sufficient baseline PM emission data for appropriate regulations, and the lack of comprehensive chemical compositions of PM from AFO. Particulate matter, including PM2.5, PM10 and TSP emission rates from two high-rise tunnel-ventilated layer houses at a commercial egg production farm were determined, based on two years of measurements of PM concentrations and house ventilation rates. In addition, the concentrations of PM2.5 and PM10 were simultaneously measured using TEOM monitors at four ambient locations in the vicinity of the farm for over two years. Furthermore, Partisol 2300 PM2.5 speciation samplers were used to take daily PM2.5 samples in the layer house and at the four ambient stations. Comprehensive chemical composition analyses included: mass, major ions (NH4+, Na+, K+, SO42-, Cl-, and NO3-), elements, organic carbon (OC) and element carbon (EC). The Winsorized 95% confidence intervals of PM2.5 emission rates were [0.44, 0.63] mg/d-hen in one house (house 3), and [0.45, 0.64] mg/d-hen in the other house (house 4); the Winsorized 95% confidence intervals of PM10 emission rates were [15.1, 15.7] mg/d-hen in house 3, and [17.7, 18.4] mg/d-hen in the house 4; the Winsorized 95% confidence intervals of TSP emission rates were [32.2, 35.7] mg/d-hen in the house 3, and [39.9, 43.5] mg/d-hen in the house 4. Hen activity, house ventilation, temperature/RH and house NH3 emissions demonstrated significant impacts on PM emissions. For both PM2.5 and PM10 concentrations, the downwind concentrations were higher than upwind concentrations. Although the strength of the linear relationship between ambient PM concentrations and house PM emissions was relatively weak, the relationship was significant at probability level of 0.05. None of the ambient PM concentrations exceeded National Ambient Air Quality Standards for 24-hour PM2.5 and PM 10 standards. Organic carbon accounted for above 50% of the total PM 2.5 mass in both house and ambient stations. NH4+ , SO42-, and NO3- accounted for about 40% of the total PM2.5 mass in ambient locations but only 12% of the total PM2.5 mass in house. The measured PM 2.5 masses agreed with the sums of the masses of the chemical components at all sampling stations except for house station. Based on a thermodynamic simulation, PM2.5 had nonlinear response to NH3, HNO 3, H2SO4 precursor gases. In the vicinity of this AFO, PM2.5 mass concentrations were not sensitive to the change of NH3.;This study provides scientific data for developing and validating PM emission models. The comprehensive chemical composition data, spatial and temporal variations of PM add quantitative information for future studies of health, environmental impact and sustainability of egg production systems.