Lake Baikal is the biggest reservoir of fresh water with unique flora and fauna; presently it is negatively affected by climate change, water warming, industrial emissions, shipping, touristic activities, and Siberian forestfires. The assessment of air pollution-related Baikal\'s ecosystem damage is an unsolved problem. Ship, based expedition exploring the Baikal at-mospheric aerosol loading, was performed over the lake area in July 2018. We combine the aerosol near-water and vertical distributions over the Lake Baikal basin with meteorolog-ical observations and air mass transportation simulations. Lidar sounding of aerosolfields in the troposphere assesses the atmospheric background in the pristine areas and the pol-lution during fire-affected periods. Aerosol optical properties (scattering and spectral ab-sorption) converted to the particle number size, black carbon (BC) mass, and Absorption Angstrom Exponent (AAE) provide the inside into aerosol characterization. Transport of in-dustrial emissions from Krasnoyarsk and Irkutsk regions, and wildfire plumes from Repub-lic of Yakutia relates the pollution sources to the increased concentrations of fine particle numbers, PM10 and BC mass over Southern and Northern/Central Baikal, respectively. The highest PM10 and BC are associated to the harbor and touristic areas of intensive shipping and residential biomass burning. Deposition estimates applied to aerosol data exhibit the pollutionfluxes to water surface over the whole Baikal area. AAE marks the impact of coal combustion, residential biomass burning, and wildfires indicating the high pollution level of the Lake Baikal ecological system .