Data on primary aerosol properties during “Boreal and savannah fire aerosol ageing” (BASFAA) campaign at the ILMARI combustion facility in Kuopio, Finland, in May - June 2022. Missing data is indicated by NaN Files: BASFAA_emission_factors.dat modified combustion efficiency (MCE) and uncertainty emission factors (EF) and uncertainty BASFAA_Mie_model_MAC_BC.dat modelled mass absorption coefficient (MAC) for black carbon (BC) at different wavelengths and core/shell ratio BASFAA_primary_aerosol_mass.dat mass concentrations of BC and the non-refractory components observed by AMS BASFAA_primary_effective_density.dat aerosol particle effective density as function of particle size BASFAA_primary_FIGAERO_VBS.dat particle phase volatility distribution from FIGAERO BASFAA_primary_optical_properties.dat integrated scattering coefficient, truncation corrected absorption coefficient, corrected using Collaud Coen (Atmos. Meas. Tech. 2010) and Cref=3.5 single scattering albedo (SSA) and uncertainty absorption Ångström exponent (AAE) and unertainty BASFAA_primary_particle_size_distribution.dat aerosol particle number size distribution [dN / dlogDp] BASFAA_primary_rBC_mass_size_distribution.dat BC particle mass size distribution [dM / dlogDp] BASFAA_primary_rBC_number_size_distribution.dat BC particle number size distribution [dN / dlogDp] BASFAA_primary_vocus.dat volatile organic compound (VOC) concentrations from Vocus BASFAA_primary_vocus_VBS.dat gas phase volatility distribution from Vocus