engleski

Combined analysis using AMS and EESI measures for organic aerosol source apportionment of the Adriatic coast

The widespread use of Aerodyne’s Aerosol Mass Spectrometer (AMS) has greatly improved real- time organic aerosol (OA) monitoring, and offline method further improved the spatial coverage and the accessibility of AMS measurements, even to locations that would not be a focal point for research. This is the case for the Rogoznica, Croatia, measurements. Aerosol of size fraction PM2.5 was collected seasonally during a 2 years period. This study is one of the first of its kind, trying to quantitatively source apportion organic aerosol data measured with AMS with the aid of molecular information obtained from the Extractive ElectroSpray Ionization (EESI) using the Positive Matrix Factorization (PMF) algorithm. This new technique can be used to enhance AMS capabilities by having a more detailed knowledge of the organic aerosol fraction composition. GF/F filters were used to collect PM2.5 aerosol size fraction. The filters were punched and water- extracted (Dällenbach et al., 2017) into samples that were then nebulized and measured simultaneously with AMS and EESI. The AMS data was processed using the Squirrel and PIKA software to obtain the mass spectra, and will be analysed as in Bozzetti et al. (2017). As for the EESI data, they will be treated following the procedures described in Lopez-Hilfiker et al. (2019). Qi et al. (2019) describe the same apportionment approach of EESI online data. A preliminary PMF result contains a 6 factor solution indicating Sulfur Containing OA, Secondary OA, Primary Biological OA, Hydrocarbon OA, and two unknown fingerprints.The available external measurement do not show strong correlations with the factors, EESI data might yield valuable molecular information to recognise the factors.

source apportionment ; novel instrument ; Croatia

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