Secondary Organic Aerosol Formation via Multiphase Reaction of Hydrocarbons in Urban Atmospheres Using the CAMx Model Integrated with the UNIPAR model

The prediction of Secondary Organic Aerosol (SOA) in regional scales is traditionally performed by using gas-particle partitioning models. In the presence of inorganic salted wet aerosols, aqueous reactions of semivolatile organic compounds can also significantly contribute to SOA formation. The UNIfied Partitioning-Aerosol phase Reaction (UNIPAR) model utilizes explicit gas chemistry to better predict SOA mass from multiphase reactions. In this work, the UNIPAR model was incorporated with the Comprehensive Air Quality Model with Extensions (CAMx) to predict the ambient concentration of organic matter (OM) in urban atmospheres during the Korean-United States Air Quality (2016 KORUS-AQ) campaign. The SOA mass predicted with the CAMx-UNIPAR model changed with varying levels of humidity and emissions and in turn, has the potential to improve the accuracy of OM simulations. The CAMx-UNIPAR model significantly improved the simulation of SOA formation under the wet condition, which often occurred during the KORUS-AQ campaign, through the consideration of aqueous reactions of reactive organic species and gas-aqueous partitioning. The contribution of aromatic SOA to total OM was significant during the low-level transport/haze period (24–31 May 2016) because aromatic oxygenated products are hydrophilic and reactive in aqueous aerosols. The OM mass predicted with the CAMx-UNIPAR model was compared with that predicted with the CAMx model integrated with the conventional two product model (SOAP). Based on estimated statistical parameters to predict OM mass, the performance of CAMx-UNIPAR was noticeably better than the conventional CAMx model although both SOA models underestimated OM compared to observed values, possibly due to missing precursor hydrocarbons such as sesquiterpenes, alkanes, and intermediate VOCs. The CAMx-UNIPAR model simulation suggested that in the urban areas of South Korea, terpene and anthropogenic emissions significantly contribute to SOA formation while isoprene SOA minimally impacts SOA formation.

Strengthening the affectivity of atmospheres in urban environments: the toolkit of multi-sensory experience

PurposeThe affectivity is conceptualised in the literary work of phenomenological theories as a significant factor in urban environments studies that are related to change people's feelings. This article aims to present toolkits for creating affective urban atmospheres, which is based on communications between people and place.Design/methodology/approachTo better comprehend the links between the felt body theory and reconstructing affective urban atmospheres in urban environments, this article has performed bibliographic investigations on the sensible approaches and presented Toolkit related to the multi-sensory experience.FindingsThis article breaks new ground to discuss the concepts of the felt body, vital drive and daily multi-sensory experience as a contribution to urban studies applications.Research limitations/implicationsThis article clarified the possibility of creating affective urban atmospheres through the concepts of affectivity as a process at a pre-design stage.Originality/valueIn conclusion, it is argued that work on multi-sensory experience in urban environments needs to address the felt body and vital drive to become a set of urban studies tools of perceptual dimension.