Mapping of Airborne Particulates in Phnom Penh,Cambodia: Comparisons with Bangkok,Thailand and Phoenix,Arizona

The city of Phnom Penh is experiencing growth and, with this growth, an increased level of air pollution in the form of airborne particles that are attributed to increased vehicle traffic in the city – vehicular exhaust and re-entrained dust. For this study, airborne particulates were counted and sorted using a six-channel laser particle counter. Initial sample counts were taken at 88 sites within the city of Phnom Penh, Cambodia, on days representative of dry season conditions. A subset of 33 sites was re-sampled on a day representative of the wet season. Objectives of this study are to provide a baseline count for airborne particulates in the city of Phnom Penh, and to explore the characteristics of the particulate counts utilizing summary statistics and maps. The median Phnom Penh city-wide fine and coarse particle counts are 1.07 *10 $^8$ /m $^3$ and 1.36*10 $^6$ /m $^3$ , respectively. While the fine particle count can be attributed to vehicle exhaust, the coarse particle count is attributed to re-entrained road dust and dirt roads. The overall coarse particle count is influenced by a number of hot spots across the city. Selective paving of these hot spots will greatly reduce the level of airborne coarse particulates.