Strong influence of deposition and vertical mixing on secondary organic aerosol concentrations in CMAQ and CAMx

Shu, Qian; Koo, Bonyoung; Yarwood, Greg; Henderson, Barron H.

doi:10.1016/j.atmosenv.2017.10.035

Cited by 10 publications

(6 citation statements)

References 31 publications

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“…Third, deposition becomes more crucial in this study since it is necessary to modify land use categories by applying different VCs; however, there still exists a gap in deposition velocity for both modeling and observation areas, making it difficult to decide the real influence of deposition velocity on our results in this study. There are several studies that have pointed out the uncertainties of particle dry deposition in air quality models [31,[35][36][37]. Thus, the results of this study could be improved in the future with updated deposition algorithms.…”

Section: Discussionmentioning

confidence: 78%

Modeling the Impacts of City-Scale “Ventilation Corridor” Plans on Human Exposure to Intra-Urban PM2.5 Concentrations

et al. 2021

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Increasingly, Chinese cities are proposing city-scale ventilation corridors (VCs) to strengthen wind velocities and decrease pollution concentrations, although their influences are ambiguous. To assess VC impacts, an effort has been made to predict the impact of VC solutions in the high density and diverse land use of the coastal city of Shanghai, China, in this paper. One base scenario and three VC scenarios, with various VC widths, locations, and densities, were first created. Then, the combination of the Weather Research and Forecasting/Single-Layer Urban Canopy Model (WRFv.3.4/UCM) and Community Multiscale Air Quality (CMAQv.5.0.1) numerical simulation models were employed to comprehensively evaluate the impacts of urban spatial form and VC plans on PM2.5 concentrations. The modeling results indicated that concentrations increased within the VCs in both summer and winter, and the upwind concentration decreased in winter. These counter-intuitive results could be explained by decreased planetary boundary layer (PBL), roughness height, deposition rate, and wind speeds induced by land use and urban height modifications. PM2.5 deposition flux decreased by 15–20% in the VCs, which was attributed to the roughness height decrease for it weakens aerodynamic resistance (Ra). PBL heights within the VCs decreased 15–100 m, and the entire Shanghai’s PBL heights also decreased in general. The modeling results suggest that VCs may not be as functional as certain urban planners have presumed.

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Section: Discussionmentioning

confidence: 78%

Modeling the Impacts of City-Scale “Ventilation Corridor” Plans on Human Exposure to Intra-Urban PM2.5 Concentrations

et al. 2021

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“…in (Shu et al, 2017), showing that CMAQ (v5.0.1) predicts larger than CAMx (v5.4.1) for large particles.…”

Section: Proposed Schemesmentioning

confidence: 91%

“…They have been widely implemented in regional-scale 3-D models because of their relatively simple formulations and few dependencies on environmental parameters. However, significant deposition differences have been reported by Shu et al (2017) between CAMx v5.4.1 (Z01) and CMAQ v5.0.1 (PR11). The underlying theory of the two schemes is described in Sections 2.1.1 and 2.1.2.…”

Section: Description Of Particle Dry Deposition Schemesmentioning

confidence: 99%

“…The ability of atmospheric models to represent dry deposition processes directly affects the skill with which they can predict particle concentrations with implications for radiative forcing and the role of particles in climate change (Emerson et al, 2020). A previous study from Shu et al (2017) found that dry deposition could cause substantial differences in secondary organic aerosol (SOA) concentrations between two regional chemical transport models (CTMs), the Community Multiscale Air Quality (CMAQ) model, and the Comprehensive Air Quality Model with extensions (CAMx), when accounting for differences in emissions, meteorology, and chemistry. However, a general lack of dry deposition measurements makes it hard to evaluate the accuracy of the model concerning this specific process.…”

Section: Introductionmentioning

confidence: 99%

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Particle dry deposition algorithms in CMAQ version 5.3: characterization of critical parameters and land use dependence using DepoBoxTool version 1.0

Shu

Murphy

Pleim

et al. 2021

Preprint

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Abstract. This study investigates particle dry deposition by characterizing critical parameters and land-use dependence in a 0-D box model as well as quantifying the resulting impact of dry deposition parameterizations on regional-scale 3-D model predictions. A publicly available box model configured with several land-use dependent dry deposition schemes is developed to evaluate predictions of several model approaches with available measurements. The 0-D box model results suggest that current dry deposition schemes in 3-D regional models underestimate particle dry deposition velocities, but this varies with size distribution properties and land-use categories. We propose two revised schemes to improve dry deposition performance in air quality models and test them in the Community Multiscale Air Quality (CMAQ) model. The first scheme improves the previous CMAQ scheme by preserving the original dry deposition impaction calculation but turning off redundant integration across particle size for each aerosol mode. The second scheme adds a dependence on leaf area index (LAI) to better estimate uptake to vegetative surfaces while using a settling velocity that is integrated across particle size for the Stokes number calculation. CMAQ model performance was evaluated for a month in July 2011 for the conterminous U.S. based on available observations of ambient sulfate (SO4) aerosol concentrations from multiple routine particulate matter monitoring networks. Incorporation of the first scheme has a larger impact on coarse particles than fine particles, systematically reducing monthly domain-wide average particle dry deposition velocities (Vd) by approximately 96% and 35%, respectively, and increasing monthly average SO4 concentrations by 395% and 21%. After incorporating LAI into the boundary layer resistance (Rb), the second scheme creates more spatial diversity of Vd and changes SO4 concentrations (coarse = −76% to +336%; fine = −7% to +18%) with land-use categories. These modifications are incorporated into the current publicly available version of CMAQ (v5.3 and beyond).

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“…As PM 2.5 is harmful to human health (Hong and Jo 2003;Lim et al 2012;Apte et al 2015;Han et al 2018), EC can cause adverse health effects, such as lung cancer and respiratory diseases (Morawska et al 2005;Hart et al 2009;Rissler et al 2012, WHO 2012Lee et al 2017). Chemically, EC is considered a non-reactive pollutant that can be transported several thousands of kilometers due to its long residence time in the atmosphere (Wolff 1981;Yu et al 2004;Khan et al 2006;Shu et al 2017). Consequently, EC can be used to trace the impact of primary emission sources (Ogren and Charlson 1984;Heintzenberg and Winkler 1991).…”

Section: Introductionmentioning

confidence: 99%

Source apportionment of ambient concentration and population exposure to elemental carbon in South Korea using a three-dimensional air quality model

Son

Kim²,

Kim

et al. 2022

Air Qual Atmos Health

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We quantified the foreign and domestic contributions to annual mean elemental carbon (EC) concentration over South Korea in 2016 using the Primary Carbon Appointment tool in the community multiscale air quality model. The individual domestic contributions were further examined by emission source category (area, mobile, and point) in each sub-region (i.e., Seoul Metropolitan Area (SMA), Gangwon, Chungcheong, Youngnam, and Honam). EC contribution and population-weighted exposure contribution (PWEC) for each emission source were calculated. Two indicators were compared and adjusted considering uncertainties of emissions from sub-regions. Based on the results of this analysis, the primary EC emission sources that need to be managed to alleviate the concentrations and PWECs were classified, and the cost-effectiveness was compared with contribution rates for EC and PWEC. The modeled annual mean EC concentration in South Korea was 0.6 µg/m3, of which 54% was contributed by foreign sources (0.3 µg/m3). However, the quarterly foreign contribution differed by up to five times depending on the monsoon, while the domestic contribution did not. Simultaneously, spatial variations of the annual mean EC contributions are smaller than those of the foreign contributions. Regardless of the uncertainty of emissions, domestic PWEC was 20% higher than the domestic concentration as domestic EC emissions were concentrated in densely populated areas. It implies that EC emission control has more significant meaning not only to improve concentration but also to improve population exposure. In addition, the contribution rate showed greater variation between sub-regions than the EC emission source categories within a region. Considering this, if the cost used to reduce a unit EC emission is the same, the cost effect can be expected when EC emissions are reduced in the sub-regions with a large contribution rate regardless of EC emission source category.

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Strong influence of deposition and vertical mixing on secondary organic aerosol concentrations in CMAQ and CAMx

Cited by 10 publications

References 31 publications

Modeling the Impacts of City-Scale “Ventilation Corridor” Plans on Human Exposure to Intra-Urban PM2.5 Concentrations

Modeling the Impacts of City-Scale “Ventilation Corridor” Plans on Human Exposure to Intra-Urban PM2.5 Concentrations

Particle dry deposition algorithms in CMAQ version 5.3: characterization of critical parameters and land use dependence using DepoBoxTool version 1.0

Source apportionment of ambient concentration and population exposure to elemental carbon in South Korea using a three-dimensional air quality model

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