Urban Fluxes of VOC during COVID-19 Lock-down in Innsbruck, Austria

Abstract:

In March 2020, the Austrian state of Tyrol experienced a rapid increase of COVID-19 cases and hotspots. On top of the national lock-down in Austria starting on March 16, Innsbruck and all Tyrolean municipalities were put under quarantine from March 19 on. Traffic and activities in public spaces were reduced substantially. The strict quarantine in Tyrol ended after nearly three weeks on April 7 relaxing into the national lock-down status; nationwide in Austria, a gradual re-opening has begun in May.

Volatile organic compounds (VOC) are released into the urban atmosphere as a consequence of various natural and anthropogenic activities [1]. The extensive disruption of public life in spring 2020 modified human activities in Innsbruck significantly giving rise to changing urban emissions. During the COVID-19 lock-down, the quarantine period and the re-opening, VOC were measured by proton-transfer-reaction time-of-flight mass spectrometry sampling from a manifold drawing ambient air from an inlet at the top of the flux tower (42.8 m above ground) of the Innsbruck Atmospheric Observatory (IAO) [2]. VOC mixing ratios at a temporal resolution of 10 Hz and collocated 3D wind vector measurements by a sonic anemometer allow for the calculation of the turbulent vertical exchange of VOC above the city employing the eddy covariance technique. Along with VOC, fluxes of carbon dioxide, nitrogen oxides and ozone are available. These data allow for an in-depth analysis of the impact of various source factors on the composition and the chemistry of the urban atmosphere.

References:

[1] Karl et al. 2018, "Urban flux measurements reveal a large pool of oxygenated volatile organic compound emissions." Proceedings of the National Academy of Sciences of the United States of America 115(6): 1186-1191.
DOI 10.1073/pnas.1714715115

[2] Karl et al. 2020, "Studying Urban Climate and Air Quality in the Alps: The Innsbruck Atmospheric Observatory." Bulletin of the American Meteorological Society 101(4): E488-E507.
DOI 10.1175/BAMS-D-19-0270.1