Online measurements of VOCs by PTR-TOF-MS in Oslo during the COVID-19 lockdown

Abstract:

Due to the COVID-19 lockdown, vehicular traffic in Oslo (Norway) decreased by 35% in March 2020 and gradually returned to normal levels until summer. In combination with favorable meteorological conditions, the traffic decrease resulted in the lowest springtime monthly average concentrations of nitrogen dioxide (NO₂) on record in the Norwegian capital over the past 10 years. As a supplement to routine air quality measurements carried out by the local authorities, we have used a proton-transfer-reaction time-of-flight mass spectrometry (PTR-ToF-MS) instrument for measuring volatile organic compounds (VOCs) in Oslo from March until June 2020. We will herein present if and how the urban VOC composition changed during the COVID-19 lockdown. A particular focus will be placed on aromatic compounds (benzene, toluene, xylene; BTX) and the impact of emissions from traffic and domestic biofuel use on atmospheric BTX levels in Oslo. The data analysis is still in progress at the time of writing of this abstract and no results can thus be included here.