Origin and transformation of organic aerosol at three background sites in Central Europe

Abstract

The source apportionment of organic aerosols (OA) in background locations is one of the important issues in contemporary air quality protection. A better understanding of the atmospheric aerosols origin and their source apportionment in different locations is essential for improving air quality.Measurements of non-refractory PM1 (NR-PM1) were simultaneously performed during winter (1st February – 10th March) and summer (1st July – 20th August)  2021 at three background sites, National Atmospheric Observatory Košetice (N 49°35′, E 15°05′; 534 m a.s.l.) and Frýdlant (N 50°94′, E 15°07′; 366 m a.s.l.) in Czech Republic, and Melpitz (N 51°32', E 12°56'; 86 m a.s.l.) in Germany. Each site was equipped with an Aerosol Mass Spectrometer: a ToF- Aerosol Chemical Speciation Monitor (ToF-ACSM) at Košetice, a Compact Time-of-Flight Aerosol Mass Spectrometer C-ToF-AMS) at Frýdlant, and a High-Resolution Time-of-Flight Aerosol Mass Spectrometer (HR-ToF-AMS) at Melpitz.A Positive Matrix Factorization (PMF) with multi-linear engine (ME-2) using Source Finder (SoFi) (Canonaco et al., 2013) was applied to OA data sets to separate OA into different factors in terms of their mass spectra and time series. Four sources of OA were identified for the winter season. Three of these sources, hydrocarbon-like organic aerosol (HOA), biomass burning organic aerosol (BBOA), and coal combustion organic aerosol (CCOA), belong to the primary sources. The last factor, designated oxidised organic aerosol (OOA), belongs to the secondary sources. Four sources of OA have also been identified for the summer season. Two of these sources were designated as primary sources (HOA and BBOA) and two as secondary sources, more oxidized organic aerosol (MO-OOA) and less oxidized organic aerosol (LO-OOA). Acknowledgements:This work was supported within a German-Czech cooperation in the TRACE project funded by the GACR under grant 20-08304J and by DFG under grant 431895563, also by the MEYS of the Czech Republic under grants ACTRIS-CZ LM2018122 and ACTRIS-CZ RI (CZ.02.1 .01 / 0.0 / 0.0 / 16_013 / 0001315), and European Union's Horizon 2020 research and innovation program ACTRIS IMP (871115). Reference:Canonaco, F., Crippa, M., Slowik, J. G., Baltensperger, U., Prévôt, A. S.: SoFi, an IGOR-based interface for the efficient use of the generalized multilinear engine (ME-2) for the source apportionment: ME-2 application to aerosol mass spectrometer data, Atmos. Measur. Tech., 6(12), 3649-3661, 2013.