Integration of airborne and ground observations of nitryl chloride in the Seoul metropolitan area and the implications on regional oxidation capacity during KORUS-AQ 2016

Abstract. Nitryl chloride (ClNO2) is a radical reservoir species that releases chlorine radicals upon photolysis. An integrated analysis of the impact of ClNO2 on regional photochemistry in the Seoul metropolitan area (SMA) during the Korea–United States Air Quality Study (KORUS-AQ) 2016 field campaign is presented. Comprehensive multiplatform observations were conducted aboard the NASA DC-8 and at two ground sites (Olympic Park, OP; Taehwa Research Forest, TRF), representing an urbanized area and a forested suburban region, respectively. Positive correlations between daytime Cl2 and ClNO2 were observed at both sites, the slope of which was dependent on O3 levels. The possible mechanisms are explored through box model simulations constrained with observations. The overall diurnal variations in ClNO2 at both sites appeared similar but the nighttime variations were systematically different. For about half of the observation days at the OP site the level of ClNO2 increased at sunset but rapidly decreased at around midnight. On the other hand, high levels were observed throughout the night at the TRF site. Significant levels of ClNO2 were observed at both sites for 4–5 h after sunrise. Airborne observations, box model calculations, and back-trajectory analysis consistently show that these high levels of ClNO2 in the morning are likely from vertical or horizontal transport of air masses from the west. Box model results show that chlorine-radical-initiated chemistry can impact the regional photochemistry by elevating net chemical production rates of ozone by ∼25 % in the morning.

[1]  J. Thornton,et al.  The effect of varying levels of surfactant on the reactive uptake of N2O5 to aqueous aerosol , 2020 .

[2]  Grant K. Sumnicht,et al.  Taehwa Research Forest: A receptor site for severe domestic pollution events in Korea during 2016. , 2019, Atmospheric chemistry and physics.

[3]  D. Jacob,et al.  The role of chlorine in global tropospheric chemistry , 2019, Atmospheric Chemistry and Physics.

[4]  S. Tilmes,et al.  Source Contributions to Carbon Monoxide Concentrations During KORUS‐AQ Based on CAM‐chem Model Applications , 2019, Journal of Geophysical Research: Atmospheres.

[5]  J. M. Reeves,et al.  ClNO2 Yields From Aircraft Measurements During the 2015 WINTER Campaign and Critical Evaluation of the Current Parameterization , 2018, Journal of Geophysical Research: Atmospheres.

[6]  J. Thornton,et al.  Airborne Observations of Reactive Inorganic Chlorine and Bromine Species in the Exhaust of Coal‐Fired Power Plants , 2018, Journal of geophysical research. Atmospheres : JGR.

[7]  Tao Wang,et al.  Heterogeneous N2O5 uptake coefficient and production yield of ClNO2 in polluted northern China: roles of aerosol water content and chemical composition , 2018, Atmospheric Chemistry and Physics.

[8]  J. D. de Gouw,et al.  Secondary organic aerosol production from local emissions dominates the organic aerosol budget over Seoul, South Korea, during KORUS-AQ , 2018, Atmospheric Chemistry and Physics.

[9]  S. Massart,et al.  Evaluating high-resolution forecasts of atmospheric CO and CO2 from a global prediction system during KORUS-AQ field campaign , 2018, Atmospheric Chemistry and Physics.

[10]  Dingli Yue,et al.  Nitrate formation from heterogeneous uptake of dinitrogen pentoxide during a severe winter haze in southern China , 2018, Atmospheric Chemistry and Physics.

[11]  Joon-Young Ahn,et al.  Impact of urban aerosol properties on cloud condensation nuclei (CCN) activity during the KORUS-AQ field campaign , 2018, Atmospheric Environment.

[12]  M. McElroy,et al.  Fine-particle pH for Beijing winter haze as inferred from different thermodynamic equilibrium models , 2018, Atmospheric Chemistry and Physics.

[13]  R. Vingarzan,et al.  Low levels of nitryl chloride at ground level: nocturnal nitrogen oxides in the Lower Fraser Valley of British Columbia , 2018 .

[14]  J. Thornton,et al.  Heterogeneous N2O5 Uptake During Winter: Aircraft Measurements During the 2015 WINTER Campaign and Critical Evaluation of Current Parameterizations , 2018 .

[15]  Shuxiao Wang,et al.  Anthropogenic Emissions of Hydrogen Chloride and Fine Particulate Chloride in China. , 2017, Environmental science & technology.

[16]  Tao Wang,et al.  Fast heterogeneous N 2 O 5 uptake and ClNO 2 production in power plant and industrial plumes observed in the nocturnal residual layer over the North China Plain , 2017 .

[17]  Yuhang Wang,et al.  High Levels of Daytime Molecular Chlorine and Nitryl Chloride at a Rural Site on the North China Plain. , 2017, Environmental science & technology.

[18]  W. Dubé,et al.  Cavity enhanced spectroscopy for measurement of nitrogen oxides in the Anthropocene: results from the Seoul tower during MAPS 2015. , 2017, Faraday discussions.

[19]  James D. Lee,et al.  Effects of halogens on European air-quality. , 2017, Faraday discussions.

[20]  T. Zhu,et al.  High N2O5 Concentrations Observed in Urban Beijing: Implications of a Large Nitrate Formation Pathway , 2017 .

[21]  Qiang Zhang,et al.  Combined impacts of nitrous acid and nitryl chloride on lower-tropospheric ozone: new module development in WRF-Chem and application to China , 2017 .

[22]  V. Shah,et al.  Sulfate production by reactive bromine: Implications for the global sulfur and reactive bromine budgets , 2017 .

[23]  Randal S. Martin,et al.  Coupling between Chemical and Meteorological Processes under Persistent Cold-Air Pool Conditions: Evolution of Wintertime PM2.5 Pollution Events and N2O5 Observations in Utah's Salt Lake Valley. , 2017, Environmental science & technology.

[24]  J. Jimenez,et al.  Fine particle pH and gas–particle phase partitioning of inorganic species in Pasadena, California, during the 2010 CalNex campaign , 2017 .

[25]  Tao Wang,et al.  Observations of N2O5 and ClNO2 at a polluted urban surface site in North China: High N2O5 uptake coefficients and low ClNO2 product yields , 2017 .

[26]  Joon-Young Ahn,et al.  Hygroscopic properties of urban aerosols and their cloud condensation nuclei activities measured in Seoul during the MAPS-Seoul campaign , 2017 .

[27]  Tao Wang,et al.  Fast heterogeneous N2O5 uptake and ClNO2 production in power plant plumes observed in the nocturnal residual layer over the North China Plain , 2017 .

[28]  Moon-Soo Park,et al.  High-resolution urban observation network for user-specific meteorological information service in the Seoul Metropolitan Area , South Korea , 2017 .

[29]  Tao Wang,et al.  Significant concentrations of nitryl chloride sustained in the morning: investigations of the causes and impacts on ozone production in a polluted region of northern China , 2016 .

[30]  Junyu Zheng,et al.  Impacts of heterogeneous uptake of dinitrogen pentoxide and chlorine activation on ozone and reactive nitrogen partitioning: improvement and application of the WRF-Chem model in southern China , 2016 .

[31]  J. Lelieveld,et al.  Estimating N 2 O 5 uptake coefficients using ambient measurements ofNO 3 , N 2 O 5 , ClNO 2 and particle-phase nitrate , 2016 .

[32]  D. Jacob,et al.  Global impacts of tropospheric halogens (Cl, Br, I) on oxidants and composition in GEOS-Chem , 2016 .

[33]  G. Wolfe,et al.  The Framework for 0-D Atmospheric Modeling (F0AM) v3.1 , 2016 .

[34]  J. Thornton,et al.  Fine particle pH and the partitioning of nitric acid during winter in the northeastern United States , 2016 .

[35]  Moon-Soo Park,et al.  High-resolution urban observation network for user-specific meteorological information service in the Seoul Metropolitan Area, South Korea , 2016 .

[36]  D. Blake,et al.  OH reactivity in urban and suburban regions in Seoul, South Korea - an East Asian megacity in a rapid transition. , 2016, Faraday discussions.

[37]  A. Middlebrook,et al.  Evaluating N2O5 heterogeneous hydrolysis parameterizations for CalNex 2010 , 2016 .

[38]  D. Blake,et al.  Nighttime chemistry at a high altitude site above Hong Kong , 2016 .

[39]  D. Blake,et al.  Observations of nitryl chloride and modeling its source and effect on ozone in the planetary boundary layer of southern China , 2015 .

[40]  M. Jenkin,et al.  The MCM v3.3.1 degradation scheme for isoprene , 2015 .

[41]  J. Bean,et al.  Inland Concentrations of Cl2 and ClNO2 in Southeast Texas Suggest Chlorine Chemistry Significantly Contributes to Atmospheric Reactivity , 2015 .

[42]  T. Bertram,et al.  Role of Organics in Regulating ClNO₂ Production at the Air-Sea Interface. , 2015, The journal of physical chemistry. A.

[43]  A. M. Booth,et al.  The first UK measurements of nitryl chloride using a chemical ionization mass spectrometer in central London in the summer of 2012, and an investigation of the role of Cl atom oxidation , 2015 .

[44]  A. Guenther,et al.  Impact of isoprene and HONO chemistry on ozone and OVOC formation in a semirural South Korean forest , 2015 .

[45]  R. Nicholls,et al.  Future Coastal Population Growth and Exposure to Sea-Level Rise and Coastal Flooding - A Global Assessment , 2015, PloS one.

[46]  Markus Müller,et al.  A compact PTR-ToF-MS instrument for airborne measurements of volatile organic compounds at high spatiotemporal resolution , 2014 .

[47]  A. Nenes,et al.  A critical evaluation of proxy methods used to estimate the acidity of atmospheric particles , 2014 .

[48]  Grant K. Sumnicht,et al.  A mobile differential absorption lidar to measure sub-hourly fluctuation of tropospheric ozone profiles in the Baltimore–Washington, D.C. region , 2014 .

[49]  D. Lowe,et al.  WRF-Chem model predictions of the regional impacts of N2O5 heterogeneous processes on night-time chemistry over north-western Europe , 2014 .

[50]  D. Lowe,et al.  Influence of aerosol chemical composition on N2O5 uptake: airborne regional measurements in northwestern Europe , 2014 .

[51]  G. Sarwar,et al.  Importance of tropospheric ClNO2 chemistry across the Northern Hemisphere , 2014 .

[52]  R. Vingarzan,et al.  Low Levels of Nitryl Chloride in the Lower Fraser Valley of British Columbia , 2014 .

[53]  J. Peischl,et al.  Chlorine as a primary radical: evaluation of methods to understand its role in initiation of oxidative cycles , 2014 .

[54]  P. Shepson,et al.  High levels of molecular chlorine in the Arctic atmosphere , 2014 .

[55]  Xiaolong Wang,et al.  Large daytime signals of N 2 O 5 and NO 3 inferred at 62 amu in a TD-CIMS: chemical interference or a real atmospheric phenomenon? , 2014 .

[56]  Yun-Ru Chen,et al.  Chlorine as a primary radical: evaluation of methods to understand its role in initiation of oxidative cycles , 2014 .

[57]  J. Thornton,et al.  An MCM modeling study of nitryl chloride (ClNO 2 ) impacts on oxidation, ozone production and nitrogen oxide partitioning in polluted continental outflow , 2013 .

[58]  J. Thornton,et al.  N2O5 uptake coefficients and nocturnal NO2 removal rates determined from ambient wintertime measurements , 2013 .

[59]  J. Thornton,et al.  Chlorine activation within urban or power plant plumes: Vertically resolved ClNO2 and Cl2 measurements from a tall tower in a polluted continental setting , 2013 .

[60]  J. D. de Gouw,et al.  Vertically resolved measurements of nighttime radical reservoirs in Los Angeles and their contribution to the urban radical budget. , 2012, Environmental science & technology.

[61]  P. Shepson,et al.  Observations of inorganic bromine (HOBr, BrO, and Br2) speciation at Barrow, Alaska, in spring 2009 , 2012 .

[62]  P. Bhave,et al.  Examining the impact of heterogeneous nitryl chloride production on air quality across the United States , 2012 .

[63]  J. D. de Gouw,et al.  Nitryl chloride and molecular chlorine in the coastal marine boundary layer. , 2012, Environmental science & technology.

[64]  L. Mielke,et al.  Observation of ClNO₂ in a mid-continental urban environment. , 2011, Environmental science & technology.

[65]  P. Shepson,et al.  A comparison of Arctic BrO measurements by chemical ionization mass spectrometry and long path‐differential optical absorption spectroscopy , 2011 .

[66]  L. Mielke,et al.  Quantification of nitryl chloride at part per trillion mixing ratios by thermal dissociation cavity ring-down spectroscopy. , 2011, Analytical chemistry.

[67]  A. Ebel,et al.  Temperature Dependent Thermodynamic Model of the System H+-NH4+-Na+-SO42--NO3--Cl--H2O , 2010 .

[68]  J. Thornton,et al.  A large atomic chlorine source inferred from mid-continental reactive nitrogen chemistry , 2010, Nature.

[69]  J. Thornton,et al.  Toward a general parameterization of N 2 O 5 reactivity on aqueous particles: the competing effects of particle liquid water, nitrate and chloride , 2009 .

[70]  Heather Simon,et al.  Emissions inventory of PM2.5 trace elements across the United States. , 2009, Environmental science & technology.

[71]  A. Ravishankara,et al.  Reactive uptake coefficients for N2O5 determined from aircraft measurements during the Second Texas Air Quality Study: Comparison to current model parameterizations , 2009 .

[72]  D. Allen,et al.  Modeling the impact of ClNO2 on ozone formation in the Houston area , 2009 .

[73]  A. Wexler,et al.  Thermodynamic Model of the System H , 2009 .

[74]  A. Ravishankara,et al.  N2O5 Oxidizes Chloride to Cl2 in Acidic Atmospheric Aerosol , 2008, Science.

[75]  A. Ravishankara,et al.  High levels of nitryl chloride in the polluted subtropical marine boundary layer , 2008 .

[76]  L. G. Huey.  Measurement of trace atmospheric species by chemical ionization mass spectrometry: speciation of reactive nitrogen and future directions. , 2007, Mass spectrometry reviews.

[77]  J. Crounse,et al.  Measurement of gas-phase hydroperoxides by chemical ionization mass spectrometry. , 2006, Analytical chemistry.

[78]  J. Thornton,et al.  The effect of varying levels of surfactant on the reactive uptake of N 2 O 5 to aqueous aerosol , 2006 .

[79]  Roger Atkinson,et al.  Evaluated kinetic and photochemical data for atmospheric chemistry: Volume III – gas phase reactions of inorganic halogens , 2006 .

[80]  A. Ravishankara,et al.  Aircraft observations of daytime NO3 and N2O5 and their implications for tropospheric chemistry , 2005 .

[81]  F. Flocke,et al.  A thermal dissociation–chemical ionization mass spectrometry (TD‐CIMS) technique for the simultaneous measurement of peroxyacyl nitrates and dinitrogen pentoxide , 2004 .

[82]  Roger Atkinson,et al.  Evaluated kinetic and photochemical data for atmospheric chemistry: Volume I - gas phase reaxtions of Ox, HOx, NOx and SOx species , 2004 .

[83]  C. George,et al.  Uptake study of ClONO2 and BrONO2 by Halide containing droplets , 2004 .

[84]  M. Rossi.  Heterogeneous reactions on salts. , 2003, Chemical reviews.

[85]  J. Thornton,et al.  N2O5 hydrolysis on sub-micron organic aerosols: the effect of relative humidity, particle phase, and particle size , 2003 .

[86]  J. D. Neece,et al.  Direct evidence for chlorine-enhanced urban ozone formation in Houston, Texas , 2003 .

[87]  D. Dabdub,et al.  Impact of chlorine emissions from sea-salt aerosol on coastal urban ozone. , 2003, Environmental science & technology.

[88]  Roger Atkinson,et al.  Gas-phase tropospheric chemistry of biogenic volatile organic compounds: a review , 2003 .

[89]  D. Blake,et al.  Description of the analysis of a wide range of volatile organic compounds in whole air samples collected during PEM-tropics A and B. , 2001, Analytical chemistry.

[90]  B. Finlayson‐Pitts,et al.  Uptake and Reaction of ClONO2on NaCl and Synthetic Sea Salt , 2001 .

[91]  J. D. Neece,et al.  Anthropogenic Sources of Chlorine and Ozone Formation in Urban Atmospheres , 2000 .

[92]  Martin D. Müller,et al.  Photolysis frequency measurements using actinic flux spectroradiometry during the PEM‐Tropics mission: Instrumentation description and some results , 1999 .

[93]  Sasha Madronich,et al.  The Role of Solar Radiation in Atmospheric Chemistry , 1999 .

[94]  T. Malone.  Coastal waters of the world: Trends, threats and strategies , 1998 .

[95]  J. R. Pearson,et al.  Intercomparison of ground‐based NO y measurement techniques , 1998 .

[96]  P. Mirabel,et al.  MULTIPHASE CHEMISTRY OF N2O5, CLNO2, AND BRNO2 , 1998 .

[97]  C. Zetzsch,et al.  Heterogeneous Interconversion Reactions of BrNO2, ClNO2, Br2, and Cl2 , 1998 .

[98]  J. Milliman,et al.  Coastal Waters of the World: Trends, Threats, and Strategies , 1997 .

[99]  Roger Atkinson,et al.  Gas-Phase Tropospheric Chemistry of Volatile Organic Compounds: 1. Alkanes and Alkenes , 1997 .

[100]  C. Zetzsch,et al.  Production and decay of ClNO2 from the reaction of gaseous N2O5 with NaCl solution: Bulk and aerosol experiments , 1997 .

[101]  J. Abbatt,et al.  Reaction Probabilities for N2O5 Hydrolysis on Sulfuric Acid and Ammonium Sulfate Aerosols at Room Temperature , 1997 .

[102]  P. Crutzen,et al.  A mechanism for halogen release from sea-salt aerosol in the remote marine boundary layer , 1996, Nature.

[103]  D. R. Hanson,et al.  Reactions of SF- 6 and I- with Atmospheric Trace Gases. , 1995 .

[104]  J. Ponche,et al.  Fate of ClNO2 over aqueous solutions containing iodide , 1995 .

[105]  D. R. Hanson,et al.  Reactions of SF6- and I- with Atmospheric Trace Gases , 1995 .

[106]  D. Blake,et al.  Meridional distributions of NOx, NOy, and other species in the lower stratosphere and upper troposphere during AASE II , 1994 .

[107]  D. R. Hanson,et al.  Reactive Uptake of ClONO2 onto Sulfuric Acid Due to Reaction with HCl and H2O , 1994 .

[108]  D. R. Hanson,et al.  Heterogeneous reactions in sulfuric acid aerosols: A framework for model calculations , 1994 .

[109]  B. Finlayson‐Pitts.  Chlorine atoms as a potential tropospheric oxidant in the marine boundary layer , 1993 .

[110]  J. Burrows,et al.  The nitrate radical: Physics, chemistry, and the atmosphere , 1991 .

[111]  B. Finlayson‐Pitts,et al.  Formation of chemically active chlorine compounds by reactions of atmospheric NaCl particles with gaseous N2O5 and ClONO2 , 1989, Nature.

[112]  R. Stull.  An Introduction to Boundary Layer Meteorology , 1988 .

[113]  D. Blanchard.  The oceanic production of atmospheric sea salt , 1985 .

[114]  Ø. Hov.  The effect of chlorine on the formation of photochemical oxidants in Southern Telemark, Norway , 1985 .

[115]  J. Troe,et al.  Analysis of the unimolecular reaction N2O5 + M ⇌ NO2 + NO3 + M , 1982 .

[116]  A. H. Woodcock.  SALT NUCLEI IN MARINE AIR AS A FUNCTION OF ALTITUDE AND WIND FORCE , 1953 .