Modeling the Impacts of Volatile Chemical Products (VCPs) on Ozone and Secondary Organic Aerosol Using the SAPRC Mechanism

JESSSICA COATS, Amirashkan Askari, Craig Stroud, Arthur W. H. Chan, University of Toronto

     Abstract Number: 422
     Working Group: Aerosol Chemistry

Abstract
Volatile Chemical Products (VCPs) are a source of Volatile Organic Compounds (VOCs) and include but are not limited to personal care products, solvents, and paints. As tailpipe VOC emissions have decreased, the focus has shifted towards VOCs from VCP sources. Once emitted, VOCs can form ozone and secondary organic aerosols (SOAs), which pose health concerns. Condensed chemical mechanisms, such as SAPRC07C are often used in chemical transport models to represent the large list of detailed, speciated VOC emissions. However, the SAPRC07C condensed mechanism has limited representation for many VOCs from VCP sources, limiting the ability to model VCPs and their impacts. To improve the representation, additional VOCs are added to the mechanism to represent VCPs. Three aspects were considered when selecting VOCs to add to the existing mechanism: the OH reactivity, SOA formation potential, and the existing SAPRC07C representation. A new speciated database for VCPs in Canada was used to determine the OH reactivity and potential to form SOA for each chemical species. Each chemical species was ranked relative to their product category and overall contribution to VCP emissions in Canada. The VOCs that contributed the most to emissions from VCPs were matched with the existing SAPRC categories to determine their current representation in the model. This approach to grouping VOCs will condense the VCP sources from over ten thousand to under thirty, allowing for improved mechanisms to be developed for the SAPRC. We evaluate the performance of this mechanisms in ECCC GEM-MACH by comparing against VOCs measured during an intensive field campaign in winter 2024 and in long term data sets in Canada.