Organic aerosol source apportionment in Zurich using an extractive electrospray ionization time-of-flight mass spectrometer (EESI-TOF-MS) – Part 2: Biomass burning influences in winter

作者：Qi Lu, Mindong Chen, Giulia Stefenelli, Veronika Pospíšilová, Yandong Tong, Amélie Bertrand, Christoph Hueglin, Xinlei Ge, Urs Baltensperger, Andrê S. H. Prévôt, Jay Gates Slowik · 发表于：Atmospheric chemistry and physics · 年份：2019 · DOI：10.5194/acp-19-8037-2019 · 被引用次数：124 · 研究领域：Atmospheric chemistry and aerosols、Air Quality and Health Impacts、Atmospheric Ozone and Climate

Real-time, in situ molecular composition measurements of the organic fraction of fine particulate matter (PM 2.5 ) remain challenging, hindering a full understanding of the climate impacts and health effects of PM 2.5 . In particular, the thermal decomposition and ionization-induced fragmentation affecting current techniques has limited a detailed investigation of secondary organic aerosol (SOA), which typically dominates OA. Here we deploy a novel extractive electrospray ionization time-of-flight mass spectrometer (EESI-TOF-MS) during winter 2017 in downtown Zurich, Switzerland, which overcomes these limitations, together with an Aerodyne high-resolution time-of-flight aerosol mass spectrometer (HR-TOF-AMS) and supporting instrumentation. Positive matrix factorization (PMF) implemented within the Multilinear Engine (ME-2) program was applied to the EESI-TOF-MS data to quantify the primary and secondary contributions to OA. An 11-factor solution was selected as the best representation of the data, including five primary and six secondary factors. Primary factors showed influence from cooking, cigarette smoke, biomass burning (two factors) and a special local unknown event occurred only during two nights. Secondary factors were affected by biomass burning (three factors, distinguished by temperature and/or wind direction), organonitrates, monoterpene oxidation, and undetermined regional processing, in particular the contributions of wood combustion. While the AMS attributed sl...