Year-round modeling of sulfate aerosol over Asia through updates of aqueous-phase oxidation and gas-phase reactions with stabilized Criegee intermediates

Itahashi, Syuichi; Uchida, Risa; Yamaji, Katsuhiko; Chatani, Satoru

doi:10.1016/j.aeaoa.2021.100123

Cited by 4 publications

(8 citation statements)

References 61 publications

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“…In addition to these five oxidants in the original CMAQ, taking into account the elevated NO 2 concentration in Chinese pollutions, − the aqueous-phase pathway in cloud via NO 2 was added in this study. This inclusion partly improved the model underestimation issue during winter in our previous study . Note that the production of SO 4 2– on the aerosol surface is not considered in this study because the specific Chinese haze events that occurred in limited areas are out of scope and our focus is on capturing SO 4 2– pollution over East Asia from the viewpoint of the background site in Japan.…”

Section: Methodsmentioning

confidence: 98%

“…Furthermore, although the default setting of CMAQ does not possess, we implemented the pH dependency rate constant for the calculation of AQ(O 2 ) using the synergistic relationship between Fe and Mn developed in our previous study. 46 These explicit treatments of Fe and Mn concentrations are major advantages of CMAQ and our study because other CTMs, such as GEOS-Chem, treat TMI concentrations as a fraction of the PM 2.5 concentration. Because of these improvements for Fe and Mn emissions and the rate constant for the calculation for AQ(O 2 ), we tested the remaining uncertainty of solubilities of Fe and Mn, as described in Section 2.2.2 .…”

Section: Methodsmentioning

confidence: 98%

“…Thus, we implemented the Transition Metal Inventory-Asia version 1.0 to calculate the emissions of Fe and Mn. Furthermore, although the default setting of CMAQ does not possess, we implemented the pH dependency rate constant for the calculation of AQ(O 2 ) using the synergistic relationship between Fe and Mn developed in our previous study . These explicit treatments of Fe and Mn concentrations are major advantages of CMAQ and our study because other CTMs, such as GEOS-Chem, treat TMI concentrations as a fraction of the PM 2.5 concentration.…”

Section: Methodsmentioning

confidence: 99%

“…This inclusion partly improved the model underestimation issue during winter in our previous study. 46 Note that the production of SO 4 2− on the aerosol surface is not considered in this study because the specific Chinese haze events that occurred in limited areas are out of scope and our focus is on capturing SO 4 2− pollution over East Asia from the viewpoint of the background site in Japan. This version 5.3.1 of CMAQ has several features to achieve the purpose of this study.…”

Section: Observation Of Aerosol and Oxygen Isotopicmentioning

confidence: 99%

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Role of Dust and Iron Solubility in Sulfate Formation during the Long-Range Transport in East Asia Evidenced by ¹⁷O-Excess Signatures

Itahashi

Hattori

Ito

et al. 2022

Environ. Sci. Technol.

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Numerical models have been developed to elucidate air pollution caused by sulfate aerosols (SO 4 2– ). However, typical models generally underestimate SO 4 2– , and oxidation processes have not been validated. This study improves the modeling of SO 4 2– formation processes using the mass-independent oxygen isotopic composition [ 17 O-excess; Δ 17 O(SO 4 2– )], which reflects pathways from sulfur dioxide (SO 2 ) to SO 4 2– , at the background site in Japan throughout 2015. The standard setting in the Community Multiscale Air Quality (CMAQ) model captured SO 4 2– concentration, whereas Δ 17 O(SO 4 2– ) was underestimated, suggesting that oxidation processes were not correctly represented. The dust inline calculation improved Δ 17 O(SO 4 2– ) because dust-derived increases in cloud-water pH promoted acidity-driven SO 4 2– production, but Δ 17 O(SO 4 2– ) was still overestimated during winter as a result. Increasing solubilities of the transition-metal ions, such as iron, which are a highly uncertain modeling parameter, decreased the overestimated Δ 17 O(SO 4 2– ) in winter. Thus, dust and high metal solubility are essential factors for SO 4 2– formation in the region downstream of China. It was estimated that the remaining mismatch of Δ 17 O(SO 4 2– ) between the observation and model can be explained by the proposed SO 4 2– formation mechanisms in Chinese pollution. These accurately modeled SO 4 2– formation mechanisms validated by Δ 17 O(SO 4 2– ) will contribute to emission regulation strategies required for better air quality and precise climate change predictions over East Asia.

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Section: Methodsmentioning

confidence: 98%

Section: Methodsmentioning

confidence: 98%

Section: Methodsmentioning

confidence: 99%

Section: Observation Of Aerosol and Oxygen Isotopicmentioning

confidence: 99%

See 2 more Smart Citations

Role of Dust and Iron Solubility in Sulfate Formation during the Long-Range Transport in East Asia Evidenced by ¹⁷O-Excess Signatures

Itahashi

Hattori

Ito

et al. 2022

Environ. Sci. Technol.

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“…The results suggested that the maximum contribution of sCIs to SO 4 2− formation accounts for 5.0 ng m −3 , which corresponds to 0.25% of the total SO 4 2− concentration, indicating lower effects of sCIs in the targeted domain compared with previous studies. 11,12 The difference in the results derives from the incorporation of unimolecular decomposition of sCIs and the reaction with (H 2 O) 2 in this study. The SO 4 2− formation from sCIs contributes to a 0.024% decrease in radiative forcing.…”

Section: Discussionmentioning

confidence: 87%

Urban-scale analysis of the seasonal trend of stabilized-Criegee intermediates and their effect on sulphate formation in the Greater Tokyo Area

Nakamura,

Hata,

Tonokura

2023

Environ. Sci.: Atmos.

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Returning long-range PM2.5 transport into the leeward of East Asia in 2021 after Chinese economic recovery from the COVID-19 pandemic

Itahashi

Yamamura

Wang

et al. 2022

Sci Rep

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Changes in the aerosol composition of sulfate (SO42−) and nitrate (NO3−) from 2012 to 2019 have been captured as a paradigm shift in the region downwind of China. Specifically, SO42− dramatically decreased and NO3− dramatically increased over downwind locations such as western Japan due to the faster reduction of SO2 emissions than NOx emissions and the almost constant trend of NH3 emissions from China. Emissions from China sharply decreased during COVID-19 lockdowns in February–March 2020, after which China’s economic situation seemed to recover going into 2021. Given this substantial change in Chinese emissions, it is necessary to clarify the impact of long-range PM2.5 transport into the leeward of East Asia. In this study, ground-based aerosol compositions observed at three sites in western Japan were analysed. The concentrations of PM2.5, SO42− and NO3− decreased in 2020 (during COVID-19) compared with 2018–2019 (before COVID-19). In 2021 (after COVID-19), PM2.5 and NO3− increased and SO42− was unchanged. This suggests the returning long-range PM2.5 transport in 2021. From numerical simulations, the status of Chinese emissions during COVID-19 did not explain this returning impact in 2021. This study shows that the status of Chinese emissions in 2021 recovered to that before COVID-19.

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Year-round modeling of sulfate aerosol over Asia through updates of aqueous-phase oxidation and gas-phase reactions with stabilized Criegee intermediates

Cited by 4 publications

References 61 publications

Role of Dust and Iron Solubility in Sulfate Formation during the Long-Range Transport in East Asia Evidenced by ¹⁷O-Excess Signatures

Role of Dust and Iron Solubility in Sulfate Formation during the Long-Range Transport in East Asia Evidenced by ¹⁷O-Excess Signatures

Urban-scale analysis of the seasonal trend of stabilized-Criegee intermediates and their effect on sulphate formation in the Greater Tokyo Area

Returning long-range PM2.5 transport into the leeward of East Asia in 2021 after Chinese economic recovery from the COVID-19 pandemic

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Year-round modeling of sulfate aerosol over Asia through updates of aqueous-phase oxidation and gas-phase reactions with stabilized Criegee intermediates

Cited by 4 publications

References 61 publications

Role of Dust and Iron Solubility in Sulfate Formation during the Long-Range Transport in East Asia Evidenced by 17O-Excess Signatures

Role of Dust and Iron Solubility in Sulfate Formation during the Long-Range Transport in East Asia Evidenced by 17O-Excess Signatures

Urban-scale analysis of the seasonal trend of stabilized-Criegee intermediates and their effect on sulphate formation in the Greater Tokyo Area

Returning long-range PM2.5 transport into the leeward of East Asia in 2021 after Chinese economic recovery from the COVID-19 pandemic

Contact Info

Product

Resources

About

Role of Dust and Iron Solubility in Sulfate Formation during the Long-Range Transport in East Asia Evidenced by ¹⁷O-Excess Signatures

Role of Dust and Iron Solubility in Sulfate Formation during the Long-Range Transport in East Asia Evidenced by ¹⁷O-Excess Signatures