Characterizing the global tropospheric budget of oxidized nitrogen (NO y )
Abstract
Nitrogen oxides (NO x = NO + NO 2 ) in the troposphere form an array of secondary pollutants that are detrimental to air quality, ecosystems, and climate. The family of reactive oxidized nitrogen (NO y ) in the atmosphere consists of NO x and its reservoir species (e.g. HNO 3 , PAN). Our understanding of the processes underlying the transformation of NO y has advanced considerably over recent decades, however, the relative importance of NO y partitioning and loss pathways remain uncertain. In this study, we use the GEOS-Chem global chemical transport model and observations from the ATom flight campaign to assess the simulated global budget of tropospheric NO y , and the production and loss fluxes between key NO y species. Our simulation indicates that the mean global chemical lifetime of NO x is ∼ 23 h and the mean global deposition lifetime of NO y is 5.5 d. The global mean NO x :NO y ratio is 0.23 at the surface (over continents it is 0.34) and is 0.10 at 500 hPa. In addition to the four most prevalent gas-phase species (NO, NO 2 , HNO 3 , PAN) that have been central to previous descriptions of tropospheric NO y chemistry, we find that other species play key roles in driving overall chemical cycling. The model representation of organic nitrate chemistry is highly simplified and likely overestimates the importance of hydrolysis as a sink while underestimating deposition. Finally, the photolytic loss of particulate nitrate (pNO3-) to form NO 2 and HONO, as represented in our simulations, is comparable to its depositional loss, indicating the importance of further constraining this photolysis sink.
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BibTeX
@article{dutta2026characterizing,
title = {{Characterizing the global tropospheric budget of oxidized nitrogen (NO y )}},
author = {Ishir Dutta and Colette L Heald and Ilann Bourgeois and John D Crounse and Eric J Hintsa and Fred L Moore and Jeff Peischl},
journal = {Atmospheric Chemistry and Physics},
year = {2026},
month = aug,
doi = {10.5194/acp-26-11875-2026},
url = {https://hal.inrae.fr/hal-05795444v1},
note = {CC BY 4.0},
}
RIS
TY - JOUR
TI - Characterizing the global tropospheric budget of oxidized nitrogen (NO y )
AU - Ishir Dutta
AU - Colette L Heald
AU - Ilann Bourgeois
AU - John D Crounse
AU - Eric J Hintsa
AU - Fred L Moore
AU - Jeff Peischl
PY - 2026
DA - 2026/08/21
JO - Atmospheric Chemistry and Physics
DO - 10.5194/acp-26-11875-2026
UR - https://hal.inrae.fr/hal-05795444v1
AB - Nitrogen oxides (NO x = NO + NO 2 ) in the troposphere form an array of secondary pollutants that are detrimental to air quality, ecosystems, and climate. The family of reactive oxidized nitrogen (NO y ) in the atmosphere consists of NO x and its reservoir species (e.g. HNO 3 , PAN). Our understanding of the processes underlying the transformation of NO y has advanced considerably over recent decades, however, the relative importance of NO y partitioning and loss pathways remain uncertain. In this study, we use the GEOS-Chem global chemical transport model and observations from the ATom flight campaign to assess the simulated global budget of tropospheric NO y , and the production and loss fluxes between key NO y species. Our simulation indicates that the mean global chemical lifetime of NO x is ∼ 23 h and the mean global deposition lifetime of NO y is 5.5 d. The global mean NO x :NO y ratio is 0.23 at the surface (over continents it is 0.34) and is 0.10 at 500 hPa. In addition to the four most prevalent gas-phase species (NO, NO 2 , HNO 3 , PAN) that have been central to previous descriptions of tropospheric NO y chemistry, we find that other species play key roles in driving overall chemical cycling. The model representation of organic nitrate chemistry is highly simplified and likely overestimates the importance of hydrolysis as a sink while underestimating deposition. Finally, the photolytic loss of particulate nitrate (pNO3-) to form NO 2 and HONO, as represented in our simulations, is comparable to its depositional loss, indicating the importance of further constraining this photolysis sink.
SN - 1680-7316
SN - 1680-7324
ER -