In the complex situation of the plurality of emissions, an important research task remains in the Moscow megacity environment for assessment of the air quality and potential sources through aerosol composition analyses. Light absorption, PM10 mass concentration, aerosol composition, and meteorological parameters have been measured in the urban background of the Moscow megacity in spring 2017, in a period characterized by significant changes of air temperature, mass advection, and solar radiation. Organic and elemental carbon (OC, EC) as well as 76 organic compounds such as alkanes, polycyclic aromatic hydrocarbons (PAHs), oxidized PAHs, hopans, and anhydrosugars, polyols, primary and secondary saccharides, and HULIS as well as 13 ions, including K+ marker of biomass burning, are quantified for carbonaceous and inorganic aerosol composition. Correlation between Angstrom Absorption Exponent (AAE) and levoglucosan concentrations identify the relative contribution of agricultural fires and residential biomass burning (BB) around a city to urban aerosol composition. Combining the attentive analytical and statistical approaches, representative chemical compounds are developed to describe the highest quantity of variability, evaluated together with the highest analytical validity of chemical compounds. Principal component analyses (PCA) highlights the main factors from marker species relating to gasoline/diesel traffic, BB, biogenic activity, and secondary formation in the atmosphere. Identification of BB-affected periods discriminates the daily aerosol composition change with respect to air mass transportation and number of fires detected in the surrounding area of the Moscow megacity.