Halogen production from aqueous tropospheric particles

Herrmann, Hartmut; Majdik, Z.; Ervens, B.; Weise, Diana

doi:10.1016/s0045-6535(03)00202-9

Cited by 41 publications

(38 citation statements)

References 48 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Here we use the calculated rainfall rates in each grid box to determine the cloud distribution. For a nonzero rainfall rate, we assume that the grid box contains cloud particles with a mean radius of 10 μm and a number density of 70/cm 3 [ Herrmann et al , 2003]. When there is no rainfall, the grid box is assumed to contain background aerosols, in this study, a constant of surface area density of 2 μm 2 /cm 3 (=2 × 10 −8 cm 2 /cm 3 ) is given for simplification.…”

Section: Model Descriptionmentioning

confidence: 99%

Tropospheric bromine chemistry and its impacts on ozone: A model study

et al. 2005

View full text Add to dashboard Cite

[1] An off-line three-dimensional tropospheric chemical transport model, parallelTropospheric Off-Line Model of Chemistry and Transport (p-TOMCAT), has been extended by incorporating a detailed bromine chemistry scheme that contains gas-phase reactions and heterogeneous reactions on both cloud particles and background aerosols. Bromine emission from bromocarbon photo-oxidation and from sea-salt bromine depletion and bromine removal through dry and wet deposition are included. Using this model, tropospheric bromine chemistry and ozone budgets are studied. The zonal mean of the inorganic gas-phase bromine compounds (Br x ) is calculated to be high (4-8 pptv) in the lower troposphere of the midlatitudes to high latitudes in each hemisphere, with decreasing trends with altitude (down to $2-3 pptv in the upper troposphere). The lowest Br x (<2 pptv) is over low latitudes, corresponding to small sea-salt Br emission and a high rate of precipitation scavenging. A mean lifetime of $5 days is obtained for the tropospheric Br x . Sea-salt emission plays the dominant role in total Br x in the lower troposphere while organic Br-containing compounds are important in upper layers. High daytime BrO mixing ratios (>1 pptv) are found over the high-latitude ocean surface, corresponding to high tropospheric column BrO values of up to 1.6 Â 10 13 molecules/cm 2 in the monthly mean. The addition of bromine chemistry to the model leads to a reduction in tropospheric ozone amounts by 4-6% in the Northern Hemisphere and up to $30% in the Southern Hemisphere high latitudes. The net ozone loss depends not only on total Br x , but also on solar irradiance, especially at high latitudes. The hydrolysis reaction of bromine nitrate, which occurs on cloud and aerosol surfaces (BrONO 2 + H 2 O aq ! HOBr + HNO 3 ), has a significant influence on ozone chemistry through its effect on NO x as well as on reactive BrO and Br.

show abstract

Section: Model Descriptionmentioning

confidence: 99%

Tropospheric bromine chemistry and its impacts on ozone: A model study

et al. 2005

View full text Add to dashboard Cite

show abstract

“…The OH‐mediated surface reaction mechanism [ Knipping et al , 2000] is a potential source of daytime Cl 2 , but it does not appear sufficient to explain the observed levels. Box model calculations [ Yvon et al , 1996] were carried out using the parameterization of Knipping and Dabdub [2002], with a seasalt aerosol surface area of 145 um 2 cm −3 , estimated from Lewis and Schwartz [2004], for 10 m height, 5 m s −1 wind speed, 80% RH, and an aerosol Cl ‐ concentration of 5 M [ Herrmann et al , 2003]. Under these conditions, the noontime concentration of Cl 2 reached only 0.5 ppt, a factor of 7 less than observed.…”

Section: Implications For Cl2 Production Mechanismsmentioning

confidence: 99%

Measurement of Cl₂ in coastal urban air

Finley

Saltzman

2006

Geophysical Research Letters

View full text Add to dashboard Cite

[1] Measurements of Cl 2 in coastal urban air were made in Irvine, California from Aug.-Nov., 2005, using negative ion atmospheric pressure chemical ionization with tandem mass spectrometry. Cl 2 ranged from <2.5 to 20 ppt with a two month mean of 3.5 ± 3.5 ppt (1s) and an average noon photolysis rate of 44 ppt hr À1 Cl 2 . Model calculations suggest that Cl 2 photochemistry results in an increase of 5 -8 ppb in daily maximum O 3 levels, relative to a base case scenario without Cl 2 .

show abstract

“…Anthropogenic sources [1,26], aqueous reaction pathways [27,28] and naturally occurring heterogeneous or surface reaction routes of Cl2 production [25,29,30] have been proposed to explain these observations. Previous experiments have observed that Cl2 production from irradiated mixtures of O3 and particulate chloride proceeds at a rate that is too rapid to be explained unless heterogeneous chemistry is active [30].…”

Section: Introductionmentioning

confidence: 99%

Inland Concentrations of Cl2 and ClNO2 in Southeast Texas Suggest Chlorine Chemistry Significantly Contributes to Atmospheric Reactivity

2015

View full text Add to dashboard Cite

Measurements of molecular chlorine (Cl2), nitryl chloride (ClNO2), and dinitrogen pentoxide (N2O5) were taken as part of the DISCOVER-AQ Texas 2013 campaign with a High Resolution Time-of-Flight Chemical Ionization Mass Spectrometer (HR-ToF-CIMS) using iodide (I-) as a reagent ion. ClNO2 concentrations exceeding 50 ppt were regularly detected with peak concentrations typically occurring between 7:00 a.m. and 10:00 am. Hourly averaged Cl2 concentrations peaked daily between 3:00 p.m. and 4:00 p.m., with a 29-day average of 0.9 ± 0.3 (1σ) ppt. A day-time Cl2 source of up to 35 ppt·h −1 is required to explain these observations, corresponding to a maximum chlorine radical (Cl . Modeling of the Cl2 source suggests that it can enhance daily maximum O3 and RO2• concentrations by 8%-10% and 28%-50%, respectively. Modeling of observed ClNO2 assuming a well-mixed nocturnal boundary layer indicates O3 and RO2• enhancements of up to 2.1% and 38%, respectively, with a maximum impact in the early morning. These enhancements affect the formation of secondary organic aerosol and compliance with air quality standards for ozone and particulate matter.

show abstract

Halogen production from aqueous tropospheric particles

Cited by 41 publications

References 48 publications

Tropospheric bromine chemistry and its impacts on ozone: A model study

Tropospheric bromine chemistry and its impacts on ozone: A model study

Measurement of Cl₂ in coastal urban air

Inland Concentrations of Cl2 and ClNO2 in Southeast Texas Suggest Chlorine Chemistry Significantly Contributes to Atmospheric Reactivity

Contact Info

Product

Resources

About

Halogen production from aqueous tropospheric particles

Cited by 41 publications

References 48 publications

Tropospheric bromine chemistry and its impacts on ozone: A model study

Tropospheric bromine chemistry and its impacts on ozone: A model study

Measurement of Cl2 in coastal urban air

Inland Concentrations of Cl2 and ClNO2 in Southeast Texas Suggest Chlorine Chemistry Significantly Contributes to Atmospheric Reactivity

Contact Info

Product

Resources

About

Measurement of Cl₂ in coastal urban air