Seasonal modeling analysis of nitrate formation pathways in Yangtze River Delta region, China DOI Creative Commons
Jinjin Sun, Momei Qin, Xiaodong Xie

et al.

Atmospheric chemistry and physics, Journal Year: 2022, Volume and Issue: 22(18), P. 12629 - 12646

Published: Sept. 28, 2022

Abstract. Nitrate (NO3−) has been the dominant and least reduced chemical component of fine particulate matter (PM2.5) since stringent emission controls implemented in China 2013. The formation pathways NO3− vary seasonally differ substantially daytime vs. nighttime. They are affected by precursor emissions, atmospheric oxidation capacity, meteorological conditions. Understanding provides insights for design effective control strategies to mitigate pollution. In this study, Community Multiscale Air Quality (CMAQ) model was applied investigate impact regional transport, predominant physical processes, different total nitrate (TNO3, i.e., HNO3+ NO3−) production Yangtze River Delta (YRD) region during four seasons 2017. NO3-/PM2.5 NO3-/TNO3 highest winter, reaching 21 % 94 %, respectively. adjusted gas ratio (adjGR = ([NH3]+ [NO3−])/([HNO3]+ [NO3−])) YRD is generally greater than 2 across most areas YRD, indicating that mostly NH3-rich regime limited HNO3 formation. Local emissions transportation contribute concentrations throughout 50 %–62 38 %–50 majority transport contributed indirect (i.e., formed transported precursors reacting with local precursors). Aerosol (AERO, including condensation, coagulation, new particle formation, aerosol growth) processes source summer, dominated AERO (TRAN, sum horizontal vertical transport) processes. OH + NO2 pathway contributes 60 %–83 TNO3 production, N2O5 heterogeneous (HET N2O5) 10 %–36 region. HET contribution becomes more important cold warm seasons. Within planetary boundary layer Shanghai, day (98 %) summer spring night (61 winter. contributions dominate day, while dominates at night.

Language: Английский

Enhanced Particulate Nitrate Formation in Residual Layer Exacerbates Near‐Surface Pollution: Insights From Tethered Airship and Long‐Term Ground Measurements DOI Creative Commons
Peng Sun, Jiaping Wang, Yuliang Liu

et al.

Journal of Geophysical Research Atmospheres, Journal Year: 2025, Volume and Issue: 130(4)

Published: Feb. 14, 2025

Abstract Recent years have witnessed a surge in nitrate‐driven aerosol pollution across China with N 2 O 5 hydrolysis emerging as critical formation pathway. Common surface measurements may misleadingly imply this process due to low nighttime ozone at level winter. However, our study reveals more complex picture by unveiling the vertical dynamics of nitrate through an integration tethered airship campaign, long‐term ground measurements, and model simulations. Interestingly, we observed rapid growth approximately 400 m altitude, where box revealed optimal conditions for sustained nocturnal production. The accumulated overnight residual layer (RL) is transported downward next morning boundary breaks down, substantially increasing surface‐level thus exacerbating pollution. Annual‐averaged diurnal patterns measured station clearly confirm increase. mixing from RL contributes up 80% total 10:00 LT its influence persisting 31% even after sunset. Air mass trajectory analysis further confirms that emissions city‐cluster significantly contribute downwind transporting pollutants into RL. This research underscores important role chemical processes, facilitated elevated ozone, shaping It highlights indispensability profiling understanding advocates regionally coordinated control strategies eastern China.

Language: Английский

Citations

1
On the contribution of nocturnal heterogeneous reactive nitrogen chemistry to particulate matter formation during wintertime pollution events in Northern Utah DOI Creative Commons
Erin E. McDuffie, Caroline C. Womack, D. L. Fibiger

et al.

Atmospheric chemistry and physics, Journal Year: 2019, Volume and Issue: 19(14), P. 9287 - 9308

Published: July 19, 2019

Abstract. Mountain basins in Northern Utah, including the Salt Lake Valley (SLV), suffer from wintertime air pollution events associated with stagnant atmospheric conditions. During these events, fine particulate matter concentrations (PM2.5) can exceed national ambient quality standards. Previous studies SLV have found that PM2.5 is primarily composed of ammonium nitrate (NH4NO3), formed condensation gas-phase ammonia (NH3) and nitric acid (HNO3). Additional several western basins, SLV, suggested production HNO3 nocturnal heterogeneous N2O5 uptake dominant source NH4NO3 during winter. The rate this process, however, remains poorly quantified, part due to limited vertical measurements above surface, where chemistry most active. 2017 Utah Winter Fine Particulate Study (UWFPS) provided first aircraft detailed chemical composition SLV. Coupled ground-based observations, analyses day- nighttime research flights confirm principally NH4NO3, by HNO3. Here, observations box model assess contribution aerosol using NO3- rate, coefficient (γ(N2O5)), yield ClNO2 (φ(ClNO2)), which had medians 1.6 µg m−3 h−1, 0.076, 0.220, respectively. While fit values γ(N2O5) may be biased high a potential under-measurement surface area, other quantities are unaffected. Lastly, additional simulations suggest produces between 2.4 3.9 per day when considering possible effects dilution. This sufficient account for 52 %–85 % daily observed surface-level buildup nitrate, though accurate quantification dependent on modeled dilution, mixing processes, photochemistry.

Language: Английский

Citations

66
Multiple Impacts of Aerosols on O3 Production Are Largely Compensated: A Case Study Shenzhen, China DOI
Zhaofeng Tan, Keding Lu, Xuefei Ma

et al.

Environmental Science & Technology, Journal Year: 2022, Volume and Issue: 56(24), P. 17569 - 17580

Published: Dec. 6, 2022

Tropospheric ozone (O3) is a harmful gas compound to humans and vegetation, it also serves as climate change forcer. O3 formed in the reactions of nitrogen oxides volatile organic compounds (VOCs) with light. In this study, an pollution episode encountered Shenzhen, South China 2018 was investigated illustrate influence aerosols on local production. We used box model comprehensive heterogeneous mechanisms empirical prediction photolysis rates reproduce episode. Results demonstrate that aerosol light extinction NO2 showed comparable but opposite signs Hence, from different processes largely counteracted. Sensitivity tests suggest production increases further reduction while continued NOx finally shifts NOx-limited regime respect traditional O3-NOx-VOC sensitivity. Our results shed role highlight mitigation not only limiting helping ease particulate nitrate, path for cocontrol fine particle pollution.

Language: Английский

Citations

32
Formation mechanism and control strategy for particulate nitrate in China DOI
Haichao Wang,

Keding Lu,

Zhaofeng Tan

et al.

Journal of Environmental Sciences, Journal Year: 2022, Volume and Issue: 123, P. 476 - 486

Published: Sept. 26, 2022

Language: Английский

Citations

31
Seasonal modeling analysis of nitrate formation pathways in Yangtze River Delta region, China DOI Creative Commons
Jinjin Sun, Momei Qin, Xiaodong Xie

et al.

Atmospheric chemistry and physics, Journal Year: 2022, Volume and Issue: 22(18), P. 12629 - 12646

Published: Sept. 28, 2022

Abstract. Nitrate (NO3−) has been the dominant and least reduced chemical component of fine particulate matter (PM2.5) since stringent emission controls implemented in China 2013. The formation pathways NO3− vary seasonally differ substantially daytime vs. nighttime. They are affected by precursor emissions, atmospheric oxidation capacity, meteorological conditions. Understanding provides insights for design effective control strategies to mitigate pollution. In this study, Community Multiscale Air Quality (CMAQ) model was applied investigate impact regional transport, predominant physical processes, different total nitrate (TNO3, i.e., HNO3+ NO3−) production Yangtze River Delta (YRD) region during four seasons 2017. NO3-/PM2.5 NO3-/TNO3 highest winter, reaching 21 % 94 %, respectively. adjusted gas ratio (adjGR = ([NH3]+ [NO3−])/([HNO3]+ [NO3−])) YRD is generally greater than 2 across most areas YRD, indicating that mostly NH3-rich regime limited HNO3 formation. Local emissions transportation contribute concentrations throughout 50 %–62 38 %–50 majority transport contributed indirect (i.e., formed transported precursors reacting with local precursors). Aerosol (AERO, including condensation, coagulation, new particle formation, aerosol growth) processes source summer, dominated AERO (TRAN, sum horizontal vertical transport) processes. OH + NO2 pathway contributes 60 %–83 TNO3 production, N2O5 heterogeneous (HET N2O5) 10 %–36 region. HET contribution becomes more important cold warm seasons. Within planetary boundary layer Shanghai, day (98 %) summer spring night (61 winter. contributions dominate day, while dominates at night.

Language: Английский

Citations

31