Observations of high rates of NO2-HONO [NO subscript 2 - HONO] conversion in the nocturnal atmospheric boundary layer in Kathmandu, Nepal

Nitrous acid (HONO) plays a significant role in the atmosphere, especially in the polluted troposphere. Its photolysis after sunrise is an important source of hydroxyl free radicals (OH). Measurements of nitrous acid and other pollutants were carried out in the Kathmandu urban atmosphere during January–February 2003, contributing to the sparse knowledge of nitrous acid in South Asia. The results showed average nocturnal levels of HONO (1.7 ±0.8 ppbv), NO2 (17.9±10.2 ppbv), and PM10(0.18±0.11 mg m−3) in urban air in Kathmandu. Surprisingly high ratios of chemically formed secondary [HONO] to [NO 2] (up to 30%) were found, which indicates unexpectedly efficient chemical conversion of NO2 to HONO in Kathmandu. The ratios of [HONO]/[NO2] at night were found to be much higher than previously reported values from measurements in urban air in Europe, North America and Asia. The influences of aerosol surface, ground reactive surface, and relative humidity on NO2-HONO chemical conversion were discussed. The high humidity, strong and low inversion layer at night, and high aerosol pollution burden in Kathmandu may explain the particularly efficient conversion of NO2 to HONO. Correspondence to: Y. Yu (yyu@arb.ca.gov)

[1]  R. Prinn,et al.  Diurnal cycle of air pollution in the Kathmandu Valley, Nepal: Observations , 2009 .

[2]  H. Su,et al.  Observation of nighttime nitrous acid (HONO) formation at a non-urban site during PRIDE-PRD2004 in China , 2008 .

[3]  H. Su,et al.  Nitrous acid (HONO) and its daytime sources at a rural site during the 2004 PRIDE-PRD experiment in China , 2008 .

[4]  R. Prinn,et al.  Monocyclic Aromatic Hydrocarbons in Kathmandu During the Winter Season , 2008 .

[5]  J. Ortega,et al.  Photooxidation of α-pinene at high relative humidity in the presence of increasing concentrations of NOx , 2008 .

[6]  M. V. Ramana,et al.  Characterization of the seasonal cycle of south Asian aerosols: A regional‐scale modeling analysis , 2007 .

[7]  P. S. Praveen,et al.  Atmospheric brown clouds: Hemispherical and regional variations in long‐range transport, absorption, and radiative forcing , 2007 .

[8]  Jennifer D. Schuttlefield,et al.  An investigation of water uptake on clays minerals using ATR‐FTIR spectroscopy coupled with quartz crystal microbalance measurements , 2007 .

[9]  M. Cheng,et al.  Characteristics of Atmospheric Aerosol and Acidic Gases from Urban and Forest Sites in Central Taiwan , 2007, Bulletin of environmental contamination and toxicology.

[10]  Zang-Ho Shon,et al.  Characteristics of reactive nitrogen compounds and other relevant trace gases in the atmosphere at urban and rural areas of Korea during May–June, 2004 , 2007 .

[11]  G. Baumbach,et al.  PM10, PM2.5 and PM1.0 - emissions from industrial plants - results from measurement programmes in Germany. , 2007 .

[12]  Changlie Wey,et al.  Nitrogen Oxide (NO/NO2/HONO) Emissions Measurements in Aircraft Exhausts , 2007 .

[13]  K. Stemmler,et al.  Light induced conversion of nitrogen dioxide into nitrous acid on submicron humic acid aerosol , 2007 .

[14]  J. Abbatt,et al.  Interaction of NO2 with hydrocarbon soot: focus on HONO yield, surface modification, and mechanism. , 2007, The journal of physical chemistry. A.

[15]  Jörg Kleffmann,et al.  Daytime sources of nitrous acid (HONO) in the atmospheric boundary layer. , 2007, Chemphyschem : a European journal of chemical physics and physical chemistry.

[16]  K. Civerolo,et al.  Summertime observations of HONO, HCHO, and O3 at the summit of Whiteface Mountain, New York , 2007 .

[17]  M. Rossi,et al.  Heterogeneous chemistry of the NO3 free radical and N2O5 on decane flame soot at ambient temperature: reaction products and kinetics. , 2007, The journal of physical chemistry. A.

[18]  P. Adhikary,et al.  Ambient air quality of Kathmandu valley as reflected by atmospheric particulate matter concentrations (PM10) , 2006 .

[19]  D. Blake,et al.  Ozone production and hydrocarbon reactivity in Hong Kong, Southern China , 2006 .

[20]  Paul Thomas Griffiths,et al.  Reduction of NO2 to nitrous acid on illuminated titanium dioxide aerosol surfaces: implications for photocatalysis and atmospheric chemistry. , 2006, Chemical communications.

[21]  Bin Zhou,et al.  Observations of nitrous acid and its relative humidity dependence in Shanghai. , 2006, Journal of environmental sciences.

[22]  M. Cheng,et al.  Characteristics of gaseous HNO2, HNO3, NH3 and particulate ammonium nitrate in an urban city of Central Taiwan , 2006 .

[23]  M. Nardino,et al.  Surprisingly small HONO emissions from snow surfaces at Browning Pass, Antarctica , 2006 .

[24]  Choong-Min Kang,et al.  Source Identification and Trends in Concentrations of Gaseous and Fine Particulate Principal Species in Seoul, South Korea , 2006, Journal of the Air & Waste Management Association.

[25]  Y. Miller,et al.  New experimental and theoretical approach to the heterogeneous hydrolysis of NO2: key role of molecular nitric acid and its complexes. , 2006, The journal of physical chemistry. A.

[26]  J. Dibb,et al.  Observations of HONO by laser‐induced fluorescence at the South Pole during ANTCI 2003 , 2006 .

[27]  I. Barnes,et al.  The photolysis of ortho-nitrophenols: a new gas phase source of HONO. , 2006, Physical chemistry chemical physics : PCCP.

[28]  Jeffrey T. Roberts,et al.  Heterogeneous chemistry of carbon aerosols. , 2006, Annual review of physical chemistry.

[29]  Christian George,et al.  Photosensitized reduction of nitrogen dioxide on humic acid as a source of nitrous acid , 2006, Nature.

[30]  Xianliang Zhou,et al.  Importance of dew in controlling the air‐surface exchange of HONO in rural forested environments , 2006 .

[31]  R. A. Cox,et al.  A comprehensive evaluation of water uptake on atmospherically relevant mineral surfaces : DRIFT spectroscopy , thermogravimetric analysis and aerosol growth measurements , 2005 .

[32]  M. Scherge,et al.  A comparative investigation of thickness measurements of ultra-thin water films by scanning probe techniques , 2005, cond-mat/0512109.

[33]  R. Zellner,et al.  Water uptake on mineral dust and soot: a fundamental view of the hydrophilicity of atmospheric particles? , 2005, Faraday discussions.

[34]  C George,et al.  Photoenhanced uptake of gaseous NO2 on solid organic compounds: a photochemical source of HONO? , 2005, Faraday discussions.

[35]  K. Acker,et al.  Concentrations of nitrous acid, nitric acid, nitrite and nitrate in the gas and aerosol phase at a site in the emission zone during ESCOMPTE 2001 experiment , 2005 .

[36]  Franz Rohrer,et al.  Characterisation of the photolytic HONO-source in the atmosphere simulation chamber SAPHIR , 2004 .

[37]  K. Okitsu,et al.  A new method for the measurement of trace amounts of HONO in the atmosphere using an air-dragged aqua-membrane-type denuder and fluorescence detection. , 2004, The Analyst.

[38]  P. Wiesen,et al.  Heterogeneous conversion of NO2 and NO on HNO3 treated soot surfaces , 2004 .

[39]  Gerald Spindler,et al.  Long-term size-segregated characterization of PM10, PM2.5, and PM1 at the IfT research station Melpitz downwind of Leipzig (Germany) using high and low-volume filter samplers , 2004 .

[40]  J. Chow,et al.  Size and Geographical Variation in PM1, PM2.5 and PM10: Source Profiles from Soils in the Western United States , 2004 .

[41]  B. Gomišček,et al.  Spatial and temporal variations of PM1, PM2.5, PM10 and particle number concentration during the AUPHEP—project , 2004 .

[42]  Franz X. Meixner,et al.  Real-time measurements of ammonia, acidic trace gases and water-soluble inorganic aerosol species at a rural site in the Amazon Basin , 2004 .

[43]  P. Xie,et al.  Observations of carbon disulfide by differential optical absorption spectroscopy in Shanghai , 2004 .

[44]  R. Zellner,et al.  Kinetics of the interaction of water vapour with mineral dust and soot surfaces at T=298 K , 2004 .

[45]  Yang-sheng Liu,et al.  Wintertime indoor air levels of PM10, PM2.5 and PM1 at public places and their contributions to TSP. , 2004, Environment international.

[46]  J. Stutz,et al.  Relative humidity dependence of HONO chemistry in urban areas , 2004 .

[47]  R. Penner,et al.  The nature of water on surfaces of laboratory systems and implications for heterogeneous chemistry in the troposphere , 2004 .

[48]  B. Finlayson‐Pitts,et al.  HONO decomposition on borosilicate glass surfaces: implications for environmental chamber studies and field experiments , 2003 .

[49]  Alfred Wiedensohler,et al.  Variability of apparent particle density of an urban aerosol. , 2003, Environmental science & technology.

[50]  B. Vogel,et al.  Measured and simulated vertical profiles of nitrous acid—Part II. Model simulations and indications for a photolytic source , 2003 .

[51]  Norbert Kalthoff,et al.  Measured and simulated vertical profiles of nitrous acid—Part I: Field measurements , 2003 .

[52]  L. Gomes,et al.  The importance of carbon and mineral dust to seasonal aerosol properties in the Nepal Himalaya , 2003 .

[53]  J. Stutz,et al.  Atmospheric observations of enhanced NO2‐HONO conversion on mineral dust particles , 2003 .

[54]  B. Finlayson‐Pitts,et al.  The heterogeneous hydrolysis of NO2 in laboratory systems and in outdoor and indoor atmospheres: An integrated mechanism , 2003 .

[55]  Ulrich Platt,et al.  Impact of nitrous acid photolysis on the total hydroxyl radical budget during the Limitation of Oxidant Production/Pianura Padana Produzione di Ozono study in Milan , 2002 .

[56]  K. Civerolo,et al.  Summertime nitrous acid chemistry in the atmospheric boundary layer at a rural site in New York State , 2002 .

[57]  Ann Carine Vandaele,et al.  High-resolution Fourier transform measurement of the NO2 visible and near-infrared absorption cross sections: Temperature and pressure effects , 2002 .

[58]  M. Ammann,et al.  The impact of multiphase reactions of NO 2 with aromatics : a modelling approach , 2002 .

[59]  M. Ammann,et al.  The reaction of NO2 with solid anthrarobin (1,2,10-trihydroxy-anthracene) , 2002 .

[60]  T. Kitada,et al.  Numerical Simulation of Late Wintertime Local Flows in Kathmandu Valley, Nepal: Implication for Air Pollution Transport , 2002 .

[61]  Y. Inoue,et al.  Comparison Of Field Observation With Water Tank Experiment On Air Pollution Concentration In Kathmandu Valley , 2002 .

[62]  Yuanhang Zhang,et al.  DIURNAL VARIATIONS OF AEROSOL CHEMICAL COMPOSITIONS AND RELATED GASEOUS POLLUTANTS IN BEIJING AND GUANGZHOU , 2002, Journal of Environmental Science and Health. Part A: Toxic/Hazardous Substances and Environmental Engineering.

[63]  K. Civerolo,et al.  Measurements of atmospheric nitrous acid and nitric acid , 2002 .

[64]  K. Steffen,et al.  Vertical fluxes of NOx, HONO, and HNO3 above the snowpack at Summit, Greenland , 2002 .

[65]  Peter Wiesen,et al.  Smog chamber studies on the influence of diesel exhaust on photosmog formation , 2002 .

[66]  Chihshan Li,et al.  PM 1 /PM 2.5 /PM 10 Characteristics in the Urban Atmosphere of Taipei , 2002 .

[67]  B. Sapkota,et al.  Atmospheric turbidity over Kathmandu valley , 2002 .

[68]  V. Grassian.  Chemical Reactions of Nitrogen Oxides on the Surface of Oxide, Carbonate, Soot, and Mineral Dust Particles: Implications for the Chemical Balance of the Troposphere , 2002 .

[69]  P. Shepson,et al.  Snowpack photochemical production of HONO: A major source of OH in the Arctic boundary layer in springtime , 2001 .

[70]  Najat A. Saliba,et al.  Reaction of Gaseous Nitric Oxide with Nitric Acid on Silica Surfaces in the Presence of Water at Room Temperature , 2001 .

[71]  K. Acker,et al.  Nitrous and Nitric Acid Measurements Inside and Outside of Clouds at Mt. Brocken , 2001 .

[72]  P. Wiesen,et al.  A new instrument to measure gaseous nitrous acid (HONO) in the atmosphere. , 2001, Environmental science & technology.

[73]  Ulrich Platt,et al.  Investigations of emissions and heterogeneous formation of HONO in a road traffic tunnel , 2001 .

[74]  V. Grassian.  Heterogeneous uptake and reaction of nitrogen oxides and volatile organic compounds on the surface of atmospheric particles including oxides, carbonates, soot and mineral dust: Implications for the chemical balance of the troposphere , 2001 .

[75]  U. Baltensperger,et al.  Heterogeneous reaction of NO2 on diesel soot particles. , 2001, Environmental science & technology.

[76]  Massimo Antognozzi,et al.  Observation of molecular layering in a confined water film and study of the layers viscoelastic properties , 2001 .

[77]  V. Grassian,et al.  Heterogeneous Reaction of NO2 on Hexane Soot: A Knudsen Cell and FT-IR Study , 2000 .

[78]  N. Saliba,et al.  Laboratory studies of sources of HONO in polluted urban atmospheres , 2000 .

[79]  R. Vogt,et al.  FTIR Spectroscopic Investigation of the Mechanism and Kinetics of the Heterogeneous Reactions of NO2 and HNO3 with Soot , 2000 .

[80]  Cinzia Perrino,et al.  UV‐visible absorption cross sections of nitrous acid , 2000 .

[81]  J. Pekkanen,et al.  Concentrations and Estimated Soot Content of PM1, PM2.5, and PM10 in a Subarctic Urban Atmosphere† , 2000 .

[82]  Geert K. Moortgat,et al.  Temperature dependence of the absorption cross sections of formaldehyde between 223 and 323 K in the wavelength range 225–375 nm , 2000 .

[83]  James N. Pitts,et al.  Chemistry of the Upper and Lower Atmosphere: Theory, Experiments, and Applications , 1999 .

[84]  D. R. Hanson,et al.  Reactive uptake on hydrocarbon soot: Focus on NO2 , 1999 .

[85]  U. Baltensperger,et al.  Heterogeneous Production of Nitrous Acid on Soot in Polluted Air Masses. , 1998 .

[86]  Yaochun Shen,et al.  Icelike Water Monolayer Adsorbed on Mica at Room Temperature , 1998 .

[87]  J. Seinfeld,et al.  Atmospheric Chemistry and Physics: From Air Pollution to Climate Change , 1998 .

[88]  U. Baltensperger,et al.  Heterogeneous production of nitrous acid on soot in polluted air masses , 1998, Nature.

[89]  Peter Wiesen,et al.  Heterogeneous NO2 conversion processes on acid surfaces: possible atmospheric implications , 1998 .

[90]  R. Harrison,et al.  Measurements of Reaction Coefficients of NO2 and HONO on Aerosol Particles , 1998 .

[91]  A. Gerecke,et al.  The chemical kinetics of HONO formation resulting from heterogeneous interaction of NO2 with flame soot , 1998 .

[92]  Mitsuhiro Matsumoto,et al.  Long term measurements of atmospheric gaseous and aerosol species using an annular denuder system in Nara, Japan , 1998 .

[93]  C. Sharma.  Urban air quality of kathmandu valley “Kingdom of Nepal” , 1997 .

[94]  H. Flentje,et al.  Retrieval of aerosol properties from boundary layer extinction measurements with a DOAS System , 1997 .

[95]  Cinzia Perrino,et al.  Measurement of nitrous acid in milan, italy, by doas and diffusion denuders , 1996 .

[96]  U. Platt,et al.  Numerical analysis and estimation of the statistical error of differential optical absorption spectroscopy measurements with least-squares methods. , 1996, Applied optics.

[97]  Roy M. Harrison,et al.  Tropospheric cycle of nitrous acid , 1996 .

[98]  A. Wahner,et al.  Uptake of Nitrogen Dioxide and Nitrous Acid on Aqueous Surfaces , 1995 .

[99]  R. Harrison,et al.  Evidence for a surface source of atmospheric nitrous acid , 1994 .

[100]  R. Harrison,et al.  Accommodation coefficient for trace gas uptake using deposition profile measurement in an annular reactor , 1993 .

[101]  J. Notholt,et al.  Simultaneous Long Path Field Measurements of HNO2, CH2O and Aerosol , 1992 .

[102]  P. Dasgupta,et al.  Measurement of ambient nitrous acid and a reliable calibration source for gaseous nitrous acid , 1991 .

[103]  Y. Kanda,et al.  Chemiluminescent method for continuous monitoring of nitrous acid in ambient air. , 1990, Analytical chemistry.

[104]  A. Bongartz,et al.  Trace gas exchange at the air/water interface: Measurements of mass accommodation coefficients , 1990 .

[105]  P. Russell,et al.  Retrieval of aerosol size distribution moments from multiwavelength particulate extinction measurements , 1989 .

[106]  H. Akimoto,et al.  Photoenhancement of the Nitrous Acid Formation in the Surface Reaction of Nitrogen Dioxide and Water Vapor: Extra Radical Source in Smog Chamber Experiments. , 1987 .

[107]  J. Israelachvili,et al.  Molecular layering of water at surfaces and origin of repulsive hydration forces , 1983, Nature.

[108]  W. Stockwell,et al.  The mechanism of NO3 and HONO formation in the nighttime chemistry of the urban atmosphere , 1983 .

[109]  U. Platt,et al.  Detection of nitrous acid in the atmosphere by differential optical absorption , 1979 .

[110]  M. Box,et al.  Approximate determination of aerosol size distributions (A) , 1976 .

[111]  A. Panday.  The diurnal cycle of air pollution in the Kathmandu Valley, Nepal , 2006 .

[112]  W. Liao,et al.  Development of a photo-fragmentation/laser-induced fluorescence measurement of atmospheric nitrous acid , 2006 .

[113]  S Nava,et al.  Elemental characterization of PM10, PM2.5 and PM1 in the town of Genoa (Italy). , 2006, Chemosphere.

[114]  S. Hong,et al.  Measurements of PM10 aerosol and gas-phase nitrous acid during fall season in a semi-urban atmosphere , 2004 .

[115]  Guillermo Villena,et al.  Nitrite in rain and dew in Santiago city, Chile. Its possible impact on the early morning start of the photochemical smog , 2002 .

[116]  C. Neumann,et al.  Roadside particulate levels at 30 locations in the Kathmandu Valley, Nepal , 2002 .

[117]  D. Macayeal,et al.  Air-Snow Interactions and Atmospheric Chemistry , 2002 .

[118]  A. Reisinger.  Observations of HNO2 in the polluted winter atmosphere : possible heterogeneous production on aerosols , 2000 .

[119]  H. Bergh,et al.  Reactivity of NO2 and H2O on soot generated in the laboratory: a diffusion tube study at ambient temperature , 2000 .

[120]  P. Wiesen,et al.  Investigation of the heterogeneous NO2 conversion on perchloric acid surfaces , 1998 .

[121]  Gerhard Lammel,et al.  Nitrous acid and nitrite in the atmosphere , 1996 .

[122]  Justus Notholt,et al.  A DOAS study on the origin of nitrous acid at urban and non-urban sites , 1996 .

[123]  A. M. Dunker,et al.  An evaluation of the mechanism of nitrous acid formation in the urban atmosphere , 1994 .

[124]  J. Ponche,et al.  Mass transfer at the air/water interface: Mass accommodation coefficients of SO2, HNO3, NO2 and NH3 , 1993 .

[125]  J. Notholt,et al.  Formation of HNO2 on aerosol surfaces during foggy periods in the presence of NO and NO2 , 1991 .

[126]  F. Raes,et al.  Long path field measurements of aerosol parameters and trace gas concentrations; formation of nitrous acid during foggy periods , 1991 .

[127]  J. Notholt,et al.  Test of in situ measurements of atmospheric aerosols and trace gases by long path transmission spectroscopy , 1990 .

[128]  Gerhard Lammel,et al.  The atmospheric aerosol as a source of nitrous acid in the polluted atmosphere , 1988 .

[129]  I. Tang,et al.  Accommodation coefficient of gaseous NO2 on water surfaces , 1988 .

[130]  Oliver Lindqvist,et al.  Kinetics of the reaction between nitrogen dioxide and water vapour , 1987 .

[131]  T. A. H. A R L E Y,et al.  Measurement of Nitrous Acid in Motor Vehicle Exhaust , 2022 .