|Ph.D Student||Tartakovsky Dmitry David|
|Subject||Development of Methodology for Assessment of Particulate|
Pollutant Emissions and Dispersion from Large
Scale Area Developments
|Department||Department of Civil and Environmental Engineering||Supervisors||Professor David Broday|
|Dr. Eliahu Stern|
|Full Thesis text|
Surface mines and quarries are area sources of dust (suspended particulate matter) that are characterized, inter alia, by lack of accurate reports concerning the location of the specific mining operations and equipment. This makes it difficult to accurately determine their impact on dust concentrations outside their site boundaries and at nearby populated areas. Surveying the literature, no comprehensive research has ever been performed that studied the complex processes that control the environmental fate of emissions from open pit phosphate mines/ quarries.
This study reports methodology for estimating dispersion of emissions from various large open area operations, such as stone quarries and open pit phosphate mines in the Near East. Several sources of meteorological data (both measurements and modeling) were studied to estimate the required wind field when performing dispersion and environmental fate studies, in particular when in situ meteorological data are missing. AERMOD and CALPUFF dispersion calculations of particulate matter emissions from stone quarries were evaluated in two mountainous regions against TSP and PM10 measurements, using both observational and different formats of modeled meteorological data. The effect of the distance from the meteorological mast to the emission sources and the receptors in a complex terrain was also examined, and the effect of using lower resolution SRTM topographic data in areas where higher resolution MAPI data are not available was studied. Multiple sensitivity analyses were performed to evaluate the effect of various parameters on the emissions from mining operations. Emission factors for open pit phosphate mine operations in the Near East were estimated (indirectly) by comparing AERMOD results to concentrations measured in flat terrain near the Khneifiss open pit phosphate mine, Syria, and at Al Hassa mineworkers’ town, Jordan.
Findings of the present study indicate that, as expected, modeled wind fields in complex terrain are less accurate than in flat terrain. In cases where on-site meteorological observations are absent, like those studied in the current research, using WRF rather than MM5 for estimating the surface wind field may provide better air concentration estimations. Using modeled meteorological data for dispersion calculations in complex terrain provided less accurate pollutant concentration estimates than when using meteorological observations from stations located 2-5 km (and in some cases even ~11 km) from the source and the receptors. The smaller the distance between the meteorological measurements site, the sources and the receptors, the better are the predictions of AERMOD and CALPUFF. Differences in the AERMOD and CALPUFF predictions of the particulate matter concentrations originated from surface mines and quarries were partly due to their dry deposition algorithms. Based on the results of the present study, the common practice of deriving the emission rates for phosphate mining operations from the emission factors for surface coal mining seems reasonable, under certain assumptions. A range of emission factors, rather than a single value, was found to better satisfy the model performance.
It is expected that the findings of this research could be applied for more reliable environmental impact and risk assessments from stone quarries and surface phosphate mines.