Measurement, Analysis, and Modeling of Fine Particulate Matter in Eastern North Carolina

ammonia;inorganic aerosols;PM2.5;ISORROPIA;filter pack;hog industry;annular denuder

Goetz, Stephen ; Viney Aneja, Committee Chair,Yang Zhang, Committee Member,Pal Arya, Committee Member,Goetz, Stephen ; Viney Aneja ; Committee Chair ; Yang Zhang ; Committee Member ; Pal Arya ; Committee Member

University:North Carolina State University

关键词: ammonia;    inorganic aerosols;    PM2.5;    ISORROPIA;    filter pack;    hog industry;    annular denuder;   

Others  :  https://repository.lib.ncsu.edu/bitstream/handle/1840.16/1196/etd.pdf?sequence=1&isAllowed=y

美国|英语

来源: null

【 摘 要 】

An analysis of fine particulate mass concentrations in eastern North Carolina was conducted in order to investigate the impact of the hog industry and its emissions of ammonia into the atmosphere.This analysis included collecting acidic gas and inorganic fine particulate concentrations at a hog facility and at a site ˜10 miles away, while the regional impact of hog industry was studied with data, which was obtained from the North Carolina Division of Air Quality, for multiple regional sites (Fayetteville, Goldsboro, Jacksonville, Kenansville, Kinston, Raleigh, Wilmington).This regional fine particulate data was then simulated using ISORROPIA, a thermodynamic model that simulates the gas and aerosol equilibrium of inorganic atmospheric species.The local analysis showed the dominance of the ammonium sulfate aerosol, and the seasonal observations showed the impact of both urban areas and marine areas on this region.While no meteorological trends were seen in the local data, the time series plots showed an environment where regional sulfate plays a large part.While nitrate is present in this environment, it is present 1 order of magnitude less then the sulfate aerosol.The ammonium and sulfate values are highly correlated, and the molar ratio is consistent with the relative values of ammonium, sulfate, and nitrate present. The regional observational data analyses show that the major constituents of fine particulate matter are organic carbon, sulfate, nitrate, ammonium and elemental carbon.The observed PM2.5 concentration is positively correlated with temperature but negatively-correlated with wind speed.The correlation between PM2.5 mass and wind direction at some locations indicates the impact of the emissions from hog facilities on PM2.5 formation.The modeled results overpredict the observed results in each case, where the nitrate concentrations had the largest percentage overprediction.The predicted total inorganic PM concentrations are overpredicted by 40-45% of the observed values under conditions with median initial total PM species concentrations, median RH and median temperature.The ambient conditions with high PM precursor concentrations, low temperature and high relative humidity favor the formation of the secondary PM.The model runs of the individual days at the three speciated sites showed overprediction for all species, where some predicted values of ammonium were within a factor of 2 of the observed concentrations.