Journal article

Quantifying atmospheric nitrate formation pathways based on a global model of the oxygen isotopic composition (&Delta;<sup>17</sup>O) of atmospheric nitrate

Alexander B, Hastings M, Allman D, Dachs J, Thornton J, Kunasek S ...see all

Atmospheric Chemistry and Physics, vol. 9, issue 14 (2009) pp. 5043-5056

  • 4


    Mendeley users who have this article in their library.
  • N/A


    Citations of this article.
Sign in to save reference


The oxygen isotopic composition (117O) of at- mospheric nitrate is a function of the relative abundance of atmospheric oxidants (O3,ROx=OH+HO2+RO2) and the formation pathway of nitrate from its precursor NOx (=NO+NO2). Coupled observations and modeling of ni- trate 117O can be used to quantify the relative importance of chemical formation pathways leading to nitrate forma- tion and reduce uncertainties in the budget of reactive ni- trogen chemistry in the atmosphere. We present the first global model of atmospheric nitrate117O and compare with available observations. The largest uncertainty for calcula- tions of nitrate 117O is the unconstrained variability in the 117Ovalue of tropospheric ozone. The model shows the best agreement with a global compilation of observations when assuming a 117O value of tropospheric ozone equal to 35‰ and preferential oxidation of NOx by the terminal oxygen atoms of ozone. Calculated values of annual-mean nitrate 117O in the lowest model layer (0–200m above the surface) vary from7‰in the tropics to 41‰ in the polar-regions. The global, annual-mean tropospheric inorganic nitrate burden is dominated by nitrate formation via NO2+OH (76%), fol- lowed by N2O5 hydrolysis (18%) and NO3+DMS/HC (4%). Calculated nitrate 117O is sensitive to the relative impor- tance of each nitrate formation pathway, suggesting that ob- servations of nitrate117O can be used to quantify the impor- tance of individual reactions (e.g. N2O5 hydrolysis) leading to nitrate formation if the 117O value of ozone is known.

Get free article suggestions today

Mendeley saves you time finding and organizing research

Sign up here
Already have an account ?Sign in


  • B. Alexander

  • M. G. Hastings

  • D. J. Allman

  • J. Dachs

  • J. a. Thornton

  • S. a. Kunasek

Cite this document

Choose a citation style from the tabs below

Save time finding and organizing research with Mendeley

Sign up for free