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CMAS 2021: Modeling secondary organic aerosol formation from volatile chemical products in Los Angeles
Citation:
Pennington, E., K. Seltzer, B. Murphy, M. Qin, J. Seinfeld, AND H. Pye. CMAS 2021: Modeling secondary organic aerosol formation from volatile chemical products in Los Angeles. CMAS Conference, Chapel Hill, NORTH CAROLINA, November 01 - 05, 2021.
Impact/Purpose:
Volatile chemical products (VCPs) are commonly used consumer and industrial items that are an important source of anthropogenic emissions. This work shows VCPs are substantial contributors to fine particle, ozone, and formaldehyde pollution in Los Angeles.
Description:
Volatile chemical products (VCPs) are commonly used consumer and industrial items that are an important source of anthropogenic emissions. Organic compounds from VCPs evaporate on atmospherically relevant time scales and include many species that are secondary organic aerosol (SOA) precursors. However, the chemistry leading to SOA, particularly that of intermediate volatility organic compounds (IVOCs), has not been fully represented in regional-scale models such as the Community Multiscale Air Quality (CMAQ) model, which tend to underpredict SOA concentrations in urban areas. Here we develop a model to represent SOA formation from VCP emissions. The model incorporates a new VCP emissions inventory and categorizes new SOA precursor emissions into three classes: siloxanes, oxygenated IVOCs, and nonoxygenated IVOCs. VCPs are estimated to produce 1.67 mg m-3 of noontime SOA, doubling the current model predictions and reducing the SOA mass concentration bias from -75% to -58% when compared to observations in Los Angeles in 2010. While oxygenated and nonoxygenated VCP species are emitted in similar quantities, SOA formation is dominated by the nonoxygenated IVOCs. This work suggests that VCPs contribute up to half of anthropogenic SOA and it is necessary to better represent SOA precursors from VCPs in CMAQ algorithms to predict the urban enhancement of SOA.