Abstract View
First Insights into Chemical Pathways of New Particle Formation over Siberia, Russia
OLGA GARMASH, Ekaterina Ezhova, Mikhail Arshinov, Denis Davydov, Anastasiia Demakova, Meri Räty, Federico Bianchi, Tuukka Petäjä, Boris Belan, Markku Kulmala, University of Helsinki
Abstract Number: 467
Working Group: Aerosol Chemistry
Abstract
New particle formation (NPF) is an important atmospheric phenomenon that can affect the concentration of cloud condensation nuclei and potentially contribute to haze in urban areas. NPF has been observed in many locations around the world, from remote Polar Regions to megacities, with varying chemical and physical characteristics. Though forests are a large source of volatile organic compounds (VOCs) that can efficiently form secondary aerosol in the atmosphere, some forests, such as in Amazon and Siberia, were reported to have very infrequent NPF. In order to confirm low NPF frequency in Siberia and elucidate the possible reasons, we conducted measurements at Fonovaya station, located about 60 km from the city of Tomsk in Western Siberia, Russia. In this study, we focus on March-May 2020, when in addition to aerosol size distribution instruments, we deployed atmospheric pressure interface time-of-flight mass spectrometer (APi-TOF). APi-TOF was configured to measure the composition of natural negatively charged ions and clusters. We detected a large number of NPF events in comparison to previous years, especially in March, when it was close to 50%. We observed the change from cold to warm season around mid-April and simultaneously polluted southern air masses changed to somewhat cleaner air from the north. Changing meteorological conditions and potential increase in biogenic activity during very warm May affected the chemistry of the clusters initiating NPF events. In addition to pointing at vapours initiating the formation of molecular clusters, APi-TOF also provided us with the first insight into the origin of highly oxygenated organic molecules over Siberian forest. Our result help to construct our understanding of chemical processes connected to secondary aerosol formation in Western Siberia.