Near real-time source apportionment of carbonaceous aerosols in 13 sites across Europe

Abstract

Source apportionment by receptor modeling is used to determine the contributions of different emission sources to ambient levels of bulk Particulate Matter (PM), Black Carbon (BC), the Oxidative Potential (OP), among others. Source apportionment can be based e.g. on statistical approaches such as PMF (Positive Matrix Factorization), CMB (Chemical Mass Balance) or different properties such as absorption of particles originating from different sources (Aethalometer model). Often source apportionment analysis is time consuming and based on subjective decisions of an experienced user. As a part of RI-URBANs project an automated Near real-time source apportionment (NRT-SA) of carbonaceous aerosols is piloted on 13 sites across Europe during 2023. In all cities real-time measurements of aerosol chemical composition are conducted with the Aerosol Chemical Speciation monitor (ACSM: organics, sulphate, ammonium, nitrate and chloride) and Aethalometer (AE33: Black carbon (BC) and Brown carbon (BrC)). The measurement sites include two traffic, nine urban, one regional and one background site. NRT-SA based on PMF (Gang et al., 2022) will be used to separate the different primary (e.g. traffic, cooking, biomass combustion, coffee roastery, coal combustion) and secondary sources of organics from the ACSM data and aethalometer model (Sandradewi et al., 2008) to separate the BClf (from liquid fuel combustion) and BrCwb (from solid fuel combustion).  Prior information about the sources of organics like number of factors and reference mass spectra of primary sources from previously conducted source apportionment studies (Chen et al., 2022) in pilot cities have been utilized. The results of the NRT-SA have been validated by comparison to the offline calculated source apportionment results. Based on these extensive measurements, the chemical composition and origins of the fine aerosol fraction will further be discussed regarding the different environments of the investigated pilot sites throughout the European continent.The measurements and NRT-SA are conducted as a part of RI-URBANS’ project (Grant #101036245) , that aims to demonstrate how service tools from atmospheric research infrastructures can be adapted and enhanced in air quality monitoring networks in an interoperable and sustainable way. Chen, G., Canonaco, F., Slowik, J. G., Daellenbach, K. R., Tobler, A., Petit, J.-E., Favez, O., Stavroulas, I., Mihalopoulos, N., Gerasopoulos, E., El Haddad, I., Baltensperger, U., and Prévôt, A. S. H.: Real-Time Source Apportionment of Organic Aerosols in Three European Cities, Environ. Sci. Technol., https://doi.org/10.1021/acs.est.2c02509, 2022.Sandradewi, J., Prévôt, A. S. H., Szidat, S., Perron, N., Alfarra, M. R., Lanz, V. A., Weingartner, E., and Baltensperger, U.: Using Aerosol Light Absorption Measurements for the Quantitative Determination of Wood Burning and Traffic Emission Contributions to Particulate Matter, Environ. Sci. Technol., 42, 3316–3323, https://doi.org/10.1021/es702253m, 2008.