The vertical structure of aerosol optical and physical properties was measured by Lidar in Eastern Kyrgyzstan, Central Asia, from June 2008 to May 2009. Lidar measurements were supplemented with surface-based measurements of PM2.5 and PM10 mass and chemical composition in both size fractions. Dust transported into the region is common, being detected 33% of the time. The maximum frequency occurred in the spring of 2009. Dust transported to Central Asia comes from regional sources, for example, Taklimakan desert and Aral Sea basin, and from long-range transport, for example, deserts of Arabia, Northeast Africa, Iran, and Pakistan. Regional sources are characterized by pollution transport with maximum values of coarse particles within the planetary boundary layer, aerosol optical thickness, extinction coefficient, integral coefficient of aerosol backscatter, and minimum values of the ？ngstr？m exponent. Pollution associated with air masses transported over long distances has different characteristics during autumn, winter, and spring. During winter, dust emissions were low resulting in high values of the ？ngstr？m exponent (about 0.51) and the fine particle mass fraction (64%). Dust storms were more frequent during spring with an increase in coarse dust particles in comparison to winter. The aerosol vertical profiles can be used to lower uncertainty in estimating radiative forcing. 1. Introduction The solution to many practical problems in the field of environmental and human health protection is connected with the need for improved information about atmospheric aerosols, in particular, levels of pollution and the physicochemical properties of particles. This type of information is especially important for the Central Asian continent due to the large regions with high levels of particulate matter (PM) emissions and a lack of ambient measurement data [1]. In spite of the increasing capabilities to monitor aerosol transport from satellites, there are very limited data for surface-based vertical measurements of aerosol optical properties to validate satellite results and to provide higher spatial resolution than what can be obtained by satellites. Radiative effects of the atmospheric aerosol are mainly connected to their chemical properties [2]. Due to the lack of extensive data on aerosol vertical profiles, there are large uncertainties in forecasting atmospheric radiative forcing due to differences in the vertical profiles of the atmospheric aerosol as applied in models. The ability to retrieve information on the spatial structure of aerosols by ground-based
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