The main objective of the proposed project, Assessing the Anthropogenic and Biogenic Emissions Impact on Atmospheric Urban Fine Organic Particles in Eastern Romania. Solving the Challenge of the Aerosols Missing Mass as a One Step Forward Tool (acronym AI-FORECAST) is to provide for the first time a suitable and appropriate context to fulfil the requirements of accurately answering the constrains of the current challenges and uncertainties concerning the complex molecular organic structures of urban fine aerosols also at this very eastern site of the EU (i.e. Iasi urban area).