Despite intensive research over the past three decades, a generally accepted standard method to measure black carbon (BC) or elemental carbon (EC) still does not exist. Data on BC and EC concentrations are method specific and can differ widely. This work was motivated by the lack of any prior study that established the variability between these two measures of carbonaceous particulate matter. Measurements of BC and EC were performed at different locations across Asia and the South Pacific in both urban and suburban locations. Filter samples were collected during the winter of 2007 to the winter of 2010 and analyzed for both BC and EC. EC was measured using the Interagency Monitoring of Protected Visual Environments (IMPROVE_A) protocol. Black carbon was measured by the EELS reflectometer (Diffusion Systems, Ltd). Bangladesh had the highest correlation coefficient of 0.93. Bangkok, Thailand on the other hand had the lowest correlation coefficient of 0.34. A review of previously reported source apportionment of BC concentrations in these locations showed that New Zealand had the highest percentage (82%) of BC from biomass while Mongolia had the lowest percentage of 3.1%. The fraction of BC emissions from diesel vehicles was found predominant in Mumbai, India with values as high as 80%. Mongolia had the lowest emission of BC from diesel vehicle (5.4%) with coal-and biomass-combustion being the dominant sources.

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The Strouhal number from trapezoidal cylinders depends on the Reynolds number as well as the height ratio, which is the ratio of the height of the rear face to that of the front face. For Re=100 and 150, distributions of the Strouhal numbers show their minimum values at a height ratio of 0.7 and 0.85, respectively. However, for Re=200, the variation of Strouhal number increases as the height ratio from a square section decreases. After showing the maximum value at a height ratio of 0.7, it decreases as the height ratio decreases. It then increases again for the smaller height ratios. Movement of the flow separation point from the rear to front corners and change of secondary vortex strength are important factors in determining the shedding structure for Re=100 and 150. However, for Re=200, flow separation always occurs at the front corners. The change of secondary vortex strength and the interaction between the primary and secondary vortices influence the variation of shedding.