Cazacu et al.: Aerosol optical properties under the incidence of Saharan dust - 183 - APPLIED ECOLOGY AND ENVIRONMENTAL RESEARCH 14(3): 183-194. http://www.aloki.hu ● ISSN 1589 1623 (Print) ● ISSN 1785 0037 (Online) DOI: http://dx.doi.org/10.15666/aeer/1403_183194  2016, ALÖKI Kft., Budapest, Hungary A CASE STUDY OF THE BEHAVIOR OF AEROSOL OPTICAL PROPERTIES UNDER THE INCIDENCE OF A SAHARAN DUST INTRUSION EVENT CAZACU, M. M. 1, 2* – TUDOSE, O. G. 1, 3 – TIMOFTE, A. 1, 4 – RUSU, O. 1 – APOSTOL, L. 5 – LEONTIE, L. 1 – GURLUI, S. 1 1 Alexandru Ioan Cuza University of Iasi, Faculty of Physics, Atmosphere Optics, Spectroscopy and Lasers Laboratory (LOA-SL Iasi) Bulevardul Carol I, nr. 11, 700506 Iasi, Romania, 2 Physics Department, Gheorghe Asachi Technical University of Iasi, 59A Mangeron Blvd., 700050 Iasi, Romania 3 SC INOESY SRL, 21 Bradului Street, RO-700660, Iasi, Romania 4 National Meteorological Administration, Regional Forecast Center Bacau, 3 Timpului Str., Bacau, Romania 5 Alexandru Ioan Cuza University of Iasi, Faculty of Geography and Geology, Bulevardul Carol I, nr. 11, 700506 Iasi, Romania *Corresponding author e-mail: cazacumarius@gmail.com; phone: +40232201197; fax: +40232201150 (Received 28 th Jun 2015; accepted 23 rd Apr 2016) Abstract. In this paper a local-scale study of Saharan dust loading over Iasi city, Romania, during July 2012 is reported. The intrusion of Saharan dust above the monitoring site [Iasi_LOASL, Romania (47.19N, 27.55E)] and the variations of ozone and NO 2 concentrations are estimated by using advanced remote sensing techniques (i.e. Aerosol Robotic NETwork – AERONET, Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations – CALIPSO) and forecast models (i.e. DREAM and MAP 3D). The time interval was appropriately selected, to remove the influence of precipitation and clouds on photochemical processes. During intrusion events, the Saharan dust represents the main source for changes in optical and chemical parameters of the atmosphere. Keywords: remote sensing, AERONET, Saharan dust, aerosols, ozone Introduction Taking into account the major role of aerosols in absorption and scattering of solar radiation, which alters the optical properties of Earth's atmosphere, remote sensing techniques and modeling approach have been recently developed, providing complementary information about temporal and spatial variation of aerosol optical parameters (e.g. Single Scattering Albedo, Ångstrom exponent, Lidar ratio etc.). Recent researches confirmed that in Romania, especially in urban areas, the main sources of air pollution amend the complex mechanisms of photochemical oxidants; they produce an adverse effect on the optical properties of Earth's atmosphere and global climate change (Cazacu et al., 2015, 2011; Papayannis et al., 2014). Of all the classes of photochemical oxidants in the atmosphere, ozone and nitrogen dioxide are among the most extensively