Observations and model calculations of trace gas scavenging in a dense Saharan dust plume during MINATROC

An intensive field measurement campaign was performed in July/August 2002 at the Global Atmospheric Watch station Izaon Tenerife to study the interaction of mineral dust aerosol and tropospheric chemistry (MINA- TROC). A dense Saharan dust plume, with aerosol masses exceeding 500µg m 3 , persisted for three days. During this dust event strongly reduced mixing ratios of ROx (HO2, CH3O2 and higher organic peroxy radicals), H2O2, NOx (NO and NO2) and O3 were observed. A chemistry boxmodel, constrained by the measurements, has been used to study gas phase and heterogeneous chemistry. It appeared to be diffi- cult to reproduce the observed HCHO mixing ratios with the model, possibly related to the representation of precursor gas concentrations or the absence of dry deposition. The model calculations indicate that the reduced H2O2 mixing ratios in the dust plume can be explained by including the heteroge- neous removal reaction of HO2 with an uptake coefficient of 0.2, or by assuming heterogeneous removal of H2O2 with an accommodation coefficient of 5◊10 4 . However, these het- erogeneous reactions cannot explain the low ROx mixing ra- tios observed during the dust event. Whereas a mean daytime net ozone production rate (NOP) of 1.06 ppbv/hr occurred throughout the campaign, the reduced ROx and NOx mix- ing ratios in the Saharan dust plume contributed to a reduced NOP of 0.14-0.33 ppbv/hr, which likely explains the rela- tively low ozone mixing ratios observed during this event.

[1]  Tropospheric formaldehyde , 2005 .

[2]  Patrick Jöckel,et al.  Atmospheric Chemistry and Physics Technical note: The new comprehensive atmospheric chemistry module MECCA , 2005 .

[3]  David G. Streets,et al.  Impacts of dust on regional tropospheric chemistry during the ACE‐Asia experiment: A model study with observations , 2004 .

[4]  D. Clark,et al.  Exchange processes of volatile organic compounds above a tropical rain forest: Implications for modeling tropospheric chemistry above dense vegetation , 2004 .

[5]  D. Jacob,et al.  Testing fast photochemical theory during TRACE‐P based on measurements of OH, HO2, and CH2O , 2004 .

[6]  D. Jacob,et al.  Analysis of the atmospheric distribution, sources, and sinks of oxygenated volatile organic chemicals based on measurements over the Pacific during TRACE‐P , 2004 .

[7]  Paolo Bonasoni,et al.  Aerosol-ozone correlations during dust transport episodes , 2004 .

[8]  J. Kesselmeier,et al.  Exchange of short-chain aldehydes between Amazonian vegetation and the atmosphere , 2004 .

[9]  J. Lelieveld,et al.  Increasing Ozone over the Atlantic Ocean , 2004, Science.

[10]  D. Hauglustaine,et al.  Global modeling of heterogeneous chemistry on mineral aerosol surfaces: Influence on tropospheric ozone chemistry and comparison to observations , 2004 .

[11]  C. Zender,et al.  Mineral dust and global tropospheric chemistry: Relative roles of photolysis and heterogeneous uptake: MINERAL DUST AND TROPOSPHERIC CHEMISTRY , 2003 .

[12]  C. Usher,et al.  Reactions on mineral dust. , 2003, Chemical reviews.

[13]  J. Lelieveld,et al.  Origin of anthropogenic hydrocarbons and halocarbons measured in the summertime european outflow (on Crete in 2001) , 2003 .

[14]  P. M. Lang,et al.  Reanalysis of tropospheric CO trends: Effects of the 1997–1998 wildfires , 2003 .

[15]  J. Lelieveld,et al.  Ground-based PTR-MS measurements of reactive organic compounds during the MINOS campaign in Crete, July-August 2001 , 2003 .

[16]  J. Lelieveld,et al.  Formaldehyde over the Eastern Mediterranean during MINOS: Comparison of Airborne In-Situ Measurements with 3D-Model Results , 2003 .

[17]  Paul J. Crutzen,et al.  A model for studies of tropospheric ozone and nonmethane hydrocarbons: Model description and ozone results , 2003 .

[18]  H. Bunz,et al.  Atmospheric measurements of gas-phase HNO 3 and SO 2 using chemical ionization mass spectrometry during the MINATROC field campaign 2000 on Monte Cimone , 2002 .

[19]  J. Crowley,et al.  Ozone decomposition on Saharan dust: an experimental investigation , 2002 .

[20]  J. Mühle,et al.  Atmospheric Chemistry and Physics Ozone Production and Trace Gas Correlations during the June 2000 Minatroc Intensive Measurement Campaign at Mt. Cimone , 2022 .

[21]  P. Crutzen,et al.  Are CH2O measurements in the marine boundary layer suitable for testing the current understanding of CH4 photooxidation , 2002 .

[22]  V. Grassian,et al.  A Knudsen Cell Study of the Heterogeneous Reactivity of Nitric Acid on Oxide and Mineral Dust Particles , 2001 .

[23]  J. Abbatt,et al.  Uptake of Gas-Phase SO2 and H2O2 by Ice Surfaces: Dependence on Partial Pressure, Temperature, and Surface Acidity , 2001 .

[24]  J. Lelieveld,et al.  An Atmospheric Chemistry Interpretation of Mass Scans Obtained from a Proton Transfer Mass Spectrometer Flown over the Tropical Rainforest of Surinam , 2001 .

[25]  J. Lelieveld,et al.  Airborne observations of dust aerosol over the North Atlantic Ocean during ACE-2: Indications for heterogeneous ozone destruction , 2000 .

[26]  O. Schrems,et al.  Meridional distribution of hydroperoxides and formaldehyde in the marine boundary layer of the Atlantic (48°N-35°S) measured during the Albatross campaign , 2000 .

[27]  D. Jacob.  Heterogeneous chemistry and tropospheric ozone , 2000 .

[28]  W. Stockwell,et al.  On the budget of photooxidants in the marine boundary layer of the tropical South Atlantic , 1999 .

[29]  D. Blake,et al.  Distribution of hydrogen peroxide and methylhydroperoxide over the Pacific and South Atlantic Oceans , 1999 .

[30]  G. Carmichael,et al.  The Role of Mineral Aerosol in Tropospheric Chemistry in East Asia—A Model Study , 1999 .

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

[32]  L. Kleinman,et al.  Measurements of peroxides and related species during the 1995 summer intensive of the Southern Oxidants Study , 1998 .

[33]  M. Schultz,et al.  Trace gas measurements during the Oxidizing Capacity of the Tropospheric Atmosphere campaign 1993 at Izaña , 1998 .

[34]  A. Hansel,et al.  On-line monitoring of volatile organic compounds at pptv levels by means of proton-transfer-reaction mass spectrometry (PTR-MS) medical applications, food control and environmental research , 1998 .

[35]  E. Cuevas,et al.  Observations of the nitrate radical in the free troposphere at Izaña de Tenerife , 1997 .

[36]  R. W. Gillett,et al.  Formaldehyde production in clean marine air , 1997 .

[37]  Bruce E. Anderson,et al.  Ozone, hydroperoxides, oxides of nitrogen, and hydrocarbon budgets in the marine boundary layer over the South Atlantic , 1996 .

[38]  J. Lelieveld,et al.  Role of mineral aerosol as a reactive surface in the global troposphere , 1996 .

[39]  Jack G. Calvert,et al.  Peroxy radicals measured during Mauna Loa Observatory Photochemistry Experiment 2: The data and first analysis , 1996 .

[40]  Leonard Newman,et al.  Tropospheric formaldehyde concentration at the Mauna Loa Observatory during the Mauna Loa Observatory Photochemistry Experiment 2 , 1996 .

[41]  J. Abbatt,et al.  Heterogeneous Interactions of OH and HO2 Radicals with Surfaces Characteristic of Atmospheric Particulate Matter , 1996 .

[42]  L. K. Peters,et al.  A model investigation of summertime diurnal ozone behavior in rural mountainous locations , 1995 .

[43]  Gregory R. Carmichael,et al.  Photochemical Oxidant Processes in the Presence of Dust: An Evaluation of the Impact of Dust on Particulate Nitrate and Ozone Formation , 1994 .

[44]  E. Robinson,et al.  The Mauna Loa Observatory photochemistry experiment , 1992 .

[45]  D. R. Hanson,et al.  Measurement of hydroxyl and hydroperoxy radical uptake coefficients on water and sulfuric acid surfaces , 1992 .

[46]  J. Lelieveld,et al.  Influences of cloud photochemical processes on tropospheric ozone , 1990, Nature.

[47]  M. Zahniser,et al.  The temperature dependence of mass accommodation of sulfur dioxide and hydrogen peroxide on aqueous surfaces , 1989 .

[48]  P. Mcmurry,et al.  Mass Accommodation Coefficient for HO 2 Radicals on Aqueous Particles , 1987 .

[49]  P. Crutzen,et al.  Nitric acid cloud formation in the cold Antarctic stratosphere: a major cause for the springtime ‘ozone hole’ , 1986, Nature.

[50]  B. Heikes,et al.  Automated fluorometric method for hydrogen peroxide in air , 1986 .

[51]  B. Heikes,et al.  Effects of heterogeneous processes on NO3, HONO, and HNO3 chemistry in the troposphere , 1983 .

[52]  D. Kley,et al.  On the origin of tropospheric ozone , 1980 .

[53]  N. Fuchs,et al.  HIGH-DISPERSED AEROSOLS , 1971 .