Sources and seasonality of black carbon in Europe

Black Carbon, emitted during incomplete combustion, is harmful to human health and also an important climate forcer with a dominating warming component. When deposited on snow it decreases albedo and leads to early melting, while in the atmosphere it can absorb radiation and lead to warming. The emission sources are both anthropogenic and natural. In winter anthropogenic sources, like domestic burning are important, while during summertime black carbon from wild fires plays a major role. Black carbon concentrations are derived from observations of the aerosol absorption coefficient and then converted to an equivalent black carbon concentration and recorded at over 20 sites in Europe. However, the measurements on these sites are not homogeneous, as different mass absorption coefficients should be applied depending on location and season. For the years 2017-2022 we obtained a unified dataset of hourly black carbon concentrations for Europe.  A statistical method (a non negative matrix factorization based on different wavelengths) is used to split the observed black carbon into a fraction originating from fossil fuel and from biomass burning sources. The Lagrangian transport model FLEXPART is used in combination with the ECLIPSE and GFED emission inventories to model BC concentrations for the European sites and analyse the source regions for each source type. By comparing the observations and modelled concentrations  we are able to assess the correctness of the emission inventories, and using statistical optimization we can provide an updated emission estimate. We will present the sources and their seasonality and point to weaknesses in the emission inventories.