G01_P02

Evolution of fossil and non-fossil emission sources of carbonaceous aerosol in the Swiss Plateau from 2012 to 2020

Crova F^1,2, Strähl J², Szidat S²

¹Department of Physics, Università degli Studi di Milano, and INFN-Milano, Milan, Italy, ²Department of Chemistry, Biochemistry and Pharmaceutical Sciences, and Oeschger Centre for Climate Change Research, Bern, Switzerland

Carbonaceous aerosols are a major component of the fine fraction of atmospheric aerosol; moreover, they can influence Earth’s climate and are related to adverse health effects. Therefore, the identification and quantification of their emission sources are crucial.

In Switzerland, like in many other European countries, control strategies for ambient air pollution have focused mostly on emissions deriving from fossil fuel combustion (e.g., road traffic), but non-fossil contributions can be the predominant sources of carbonaceous aerosols in different periods of the year (e.g., biomass burning during winter) [Zotter et al., 2014]. Consequently, studying the evolution over long periods of the relative contributions of fossil and non-fossil sources of carbon is mandatory to understand the variation of their impact.

In this work, a source apportionment study of carbonaceous aerosol sources in the Swiss Plateau region from 2012 to 2020 was carried out by performing radiocarbon measurements on separated carbon fractions. Indeed, such measurements have been proved to be very effective to separate the contribution of different carbon emission sources in the atmosphere [Szidat et al., 2006]. Aerosol samples in the size fraction PM2.5 collected daily by Empa (Swiss Federal Laboratories for Material Science and Technology) in three different monitoring stations (Bern, Zurich, and Payerne) were exploited for this purpose. Radiocarbon measurements were performed by accelerator mass spectrometry (AMS) at the Laboratory for the Analysis of Radiocarbon with AMS (LARA) at the University of Bern on the total and elemental carbon fractions. Preliminary results concerning the site of Bern will be presented.