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Atmospheric Aerosol Source-Receptor Relationships: The Role of Coal-Fired Power Plants

Description: This report describes the technical progress made on the Pittsburgh Air Quality Study (PAQS) during the period of March 2005 through August 2005. Significant progress was made this project period on the source characterization, source apportionment, and deterministic modeling activities. This report highlights new data on road dust, vegetative detritus and motor vehicle emissions. For example, the results show significant differences in the composition in urban and rural road dust. A comparison of the organic of the fine particulate matter in the tunnel with the ambient provides clear evidence of the significant contribution of vehicle emissions to ambient PM. The source profiles developed from this work are being used by the source-receptor modeling activities. The report presents results on the spatial distribution of PMF-factors. The results can be grouped into three different categories: regional sources, local sources, or potentially both regional and local sources. Examples of the regional sources are the sulfate and selenium PMF-factors which most likely-represent coal fired power plants. Examples of local sources are the specialty steel and lead factors. There is reasonable correspondence between these apportionments and data from the EPA TRI and AIRS emission inventories. Detailed comparisons between PMCAMx predictions and measurements by the STN and IMPROVE measurements in the Eastern US are presented. Comparisons were made for the major aerosol components and PM{sub 2.5} mass in July 2001, October 2001, January 2002, and April 2002. The results are encouraging with average fraction biases for most species less than 0.25. The improvement of the model performance during the last two years was mainly due to the comparison of the model predictions with the continuous measurements in the Pittsburgh Supersite. Major improvements have included the descriptions: of ammonia emissions (CMU inventory), night time nitrate chemistry, EC emissions and their diurnal variation, and nitric acid dry removal.
Date: December 1, 2005
Creator: Robinson, Allen L.; Pandis, Spyros N. & Davidson, Cliff I.
Partner: UNT Libraries Government Documents Department

ATMOSPHERIC AEROSOL SOURCE-RECEPTOR RELATIONSHIPS: THE ROLE OF COAL-FIRED POWER PLANTS

Description: This report describes the technical progress made on the Pittsburgh Air Quality Study (PAQS) during the period of March 2003 through August 2003. Significant progress was made this project period on the source characterization, source apportionment, and deterministic modeling activities. Major accomplishments included: Development of an emission profile for an integrated coke production facility and simulations using PMCAMx for a two week period during July 2001. The emissions from the coke facility are dominated by carbonaceous compounds. Forty seven percent of the organic carbon mass was identified on a compound level basis. Polycyclic aromatic hydrocarbons were the dominant organic compound class in the coke emissions. Initial comparisons with the data collected in Pittsburgh suggest good agreement between the model predictions and observations. Single particle composition data appear useful for identifying primary sources. An example of this unique approach is illustrated using the Fe and Ce particle class with appear associated with steel production.
Date: November 1, 2003
Creator: Robinson, Allen L.; Pandis, Spyros N. & Davidson, Cliff I.
Partner: UNT Libraries Government Documents Department

ATMOSPHERIC AEROSOL SOURCE-RECEPTOR RELATIONSHIPS: THE ROLE OF COAL-FIRED POWER PLANTS

Description: This report describes the technical progress made on the Pittsburgh Air Quality Study (PAQS) during the period of March 2004 through August 2004. Significant progress was made this project period on the analysis of ambient data, source apportionment, and deterministic modeling activities. Results highlighted in this report include evaluation of the performance of PMCAMx+ for an air pollution episode in the Eastern US, an emission profile for a coke production facility, ultrafine particle composition during a nucleation event, and a new hybrid approach for source apportionment. An agreement was reached with a utility to characterize fine particle and mercury emissions from a commercial coal fired power. Research in the next project period will include source testing of a coal fired power plant, source apportionment analysis, emission scenario modeling with PMCAMx+, and writing up results for submission as journal articles.
Date: December 1, 2004
Creator: Robinson, Allen L.; Pandis, Spyros N. & Davidson, Cliff I.
Partner: UNT Libraries Government Documents Department

ATMOSPHERIC AEROSOL SOURCE-RECEPTOR RELATIONSHIPS: THE ROLE OF COAL-FIRED POWER PLANTS

Description: This report describes the technical progress made on the Pittsburgh Air Quality Study (PAQS) during the period of September 2003 through February 2004. Significant progress was made this project period on the analysis of ambient data, source apportionment, and deterministic modeling activities. Results highlighted in this report include chemical fractionation of the organic fraction to quantify the ratio of organic mass to organic carbon (OM/OC). The average OM/OC ratio for the 31 samples analyzed so far is 1.89, ranging between 1.62 and 2.53, which is consistent with expectations for an atmospherically processed regional aerosol. Analysis of the single particle data reveals that a on a particles in Pittsburgh consist of complex mixture of primary and secondary components. Approximately 79% of all particles measured with the instrument containing some form of carbon, with Carbonaceous Ammonium Nitrate (54.43%) being the dominant particle class. PMCAMx predictions were compared with data from more than 50 sites of the STN network located throughout the Eastern United States for the July 2001 period. OC and sulfate concentrations predicted by PMCAMx are within {+-}30% of the observed concentration at most of these sites. Spherical Aluminum Silicate particle concentrations (SAS) were used to estimate the contribution of primary coal emissions to fine particle levels at the central monitoring site. Primary emissions from coal combustion contribute on average 0.44 {+-} 0.3 {micro}g/m{sup 3} to PM{sub 2.5} at the site or 1.4 {+-} 1.3% of the total PM{sub 2.5} mass. Chemical mass balance analysis was performed to apportion the primary organic aerosol. About 70% of the primary OC emissions are from vehicular sources, with the gasoline contribution being on average three times greater than the diesel emissions in the summer.
Date: April 1, 2004
Creator: Robinson, Allen L.; Pandis, Spyros N. & Davidson, Cliff I.
Partner: UNT Libraries Government Documents Department

ATMOSPHERIC AEROSOL SOURCE-RECEPTOR RELATIONSHIPS: THE ROLE OF COAL-FIRED POWER PLANTS

Description: This report describes the technical progress made on the Pittsburgh Air Quality Study (PAQS) during the period of September 2004 through February 2005. Significant progress was made this project period on the analysis of ambient data, source apportionment, and deterministic modeling activities. The major experimental achievement this project period was the characterization of the mercury and fine particle emissions from two modern, large, commercial pulverized coal boilers. This testing completes the field work component of the Source Characterization Activity. This report highlights results from mercury emission measurements made using a dilution sampler. The measurements clearly indicate that mercury is being transformed from an oxidized to an elemental state within the dilution. However, wall effects are significant making it difficult to determine whether or not these changes occur in the gas phase or due to some interaction with the sampler walls. This report also presents results from an analysis that uses spherical aluminum silicate (SAS) particles as a marker for primary PM{sub 2.5} emitted from coal combustion. Primary emissions from coal combustion contribute only a small fraction of the PM{sub 2.5} mass (less than 1.5% in the summer and less than 3% in the winter) at the Pittsburgh site. Ambient SAS concentrations also appear to be reasonably spatially homogeneous. Finally, SAS emission factors measured at pilot-scale are consistent with measurements made at full-scale. This report also presents results from applying the Unmix and PMF models to estimate the contribution of different sources to the PM{sub 2.5} mass concentrations in Pittsburgh using aerosol composition information. Comparison of the two models shows similar source composition and contribution for five factors: crustal material, nitrate, an Fe, Mn, and Zn factor, specialty steel production, and a cadmium factor. PMF found several additional factors. Comparison between source contributions for the similar factors shows reasonable agreement between ...
Date: April 1, 2005
Creator: Robinson, Allen L.; Pandis, Spyros N. & Davidson, Cliff I.
Partner: UNT Libraries Government Documents Department

ATMOSPHERIC AEROSOL SOURCE-RECEPTOR RELATIONSHIPS: THE ROLE OF COAL-FIRED POWER PLANTS

Description: This report describes the technical progress made on the Pittsburgh Air Quality Study (PAQS) during the period of August 2001 through January of 2002. The major activity during this project period was the continuation of the ambient monitoring effort. Work also progressed on organizing the upcoming source characterization effort, and there was continued development of several three-dimensional air quality models. The first PAQS data analysis workshop for the project was held at Carnegie Mellon in December 2001. Two new instruments were added to site during this project period: a single particle mass spectrometer and an in situ VOC instrument. The single particle mass spectrometer has been deployed since the middle of September and has collected more than 150 days of data. The VOC instrument was only deployed during the intensive sampling period. Several instruments experienced operational issues during this project period. The overall data recovery rate for the project has been high.
Date: March 1, 2002
Creator: Robinson, Allen L.; Pandis, Spyros N. & Davidson, Cliff I.
Partner: UNT Libraries Government Documents Department

ATMOSPHERIC AEROSOL SOURCE-RECEPTOR RELATIONSHIPS: THE ROLE OF COAL-FIRED POWER PLANTS

Description: This report describes the technical progress made on the Pittsburgh Air Quality Study during the period of February through July of 2001. The major effort during this period involved the set-up and initiation of the ambient monitoring campaign. The central sampling station next to the Carnegie Mellon University in Scheleny Park was completed. Baseline measurements began on June 1, 2001, and the first intensive sampling period occurred between June 30, 2001 and August 3, 2001. Data were collected at both the central site and a set of satellite sites surrounding Pittsburgh. Preliminary examination of the data has been initiated. This report presents results of PM-2.5 mass and chemical composition measured on a 24-hr basis for the July intensive period. The average PM-2.5 concentration at the central monitoring site for the July intensive was 23 {micro}g/m{sup 3}. The variation in PM-2.5 levels indicates that a wide range of atmospheric conditions occurred during the month of July, and, therefore, the data will be useful for evaluating the performance of air quality models over a range of conditions. During July, the major chemical components of the PM-2.5 mass are sulfate and organic material. Elemental carbon and nitrate only contribute a small part of the PM-2.5 mass on a 24-hr average basis. Comparing the measured PM-2.5 mass and the sum of the chemical components indicates problems with the mass balance. The total measured mass tends to be larger than the sum of the major chemical components at high PM levels, and smaller than the sum of the components at low PM levels. There are many potential explanations for the observed discrepancies; however, preliminary data suggests that water may be the source of the mass balance discrepancy at high PM levels.
Date: September 1, 2001
Creator: Robinson, Allen L.; Pandis, Spyros N. & Davidson, Cliff I.
Partner: UNT Libraries Government Documents Department