Gas-particle partitioning, molecular weight, and yield of organic nitrate under different urban VOC, NO <sub> <i>x</i> </sub> , and oxidation conditions during SAPHIR-CHANEL campaign

Abstract. Oxidation of volatile organic compounds (VOCs) involving hydroxyl radicals (OH⚫) and nitrogen oxides (NOx), or nitrate radicals (NO3⚫) forms organic nitrates that undergo gas-particle partitioning, changing the lifetime of nitrogen and their deposition on ecosystems. In urban areas, VOC composition is complex, with contributions from traffic, cooking, volatile chemical products (VCPs), and biogenic emissions. Secondary organic aerosol (SOA) formation from urban VOC mixtures was investigated using chamber experiments during the SAPHIR-CHANEL campaign under realistic VOC-NOx and oxidation conditions. The yield of total organic nitrates is higher for precursor mixtures with a higher percentage of unsaturated VOCs, such as those from traffic and cooking sources (11 %–21 %), compared to VCPs and complex urban emission replicas (2 %–7 %). Enhanced particle-phase partitioning is observed under nighttime oxidation (by NO3⚫) versus daytime oxidation (by OH⚫). Particulate organic nitrates have a higher average molecular weight under nighttime conditions (330 ± 80 g mol−1) than under daytime conditions (250 ± 30 g mol−1) mainly due to a higher dimer fraction. Similarly, the mass fraction of the total organic aerosol that is organic nitrate is 2.6–4.5 times higher under nighttime than daytime conditions, likely due to higher molecular weight and lower temperatures. Although gas-phase organic nitrate composition varies substantially between precursor mixtures, bulk organic nitrate partitioning is generally similar to that of modeled oxidized monoterpene nitrates (10−4–10−2 m3 µg−1 at 18–40 °C). These findings improve understanding of bulk organic nitrate sources and properties in complex urban environments, allowing better simulations of air quality and nitrate deposition.

Authors

Institutions

Publication Details

Journal
Atmospheric chemistry and physics
Published
2026-06-17
DOI
https://doi.org/10.5194/acp-26-8425-2026
Primary Topic
Atmospheric chemistry and aerosols
Type
article
Field-Weighted Citation Impact
0.00

Funders

Controls
|||
ALL TIME
JAN
FEB
MAR
APR
MAY
JUN
JUL
AUG
SEP
OCT
article

Gas-particle partitioning, molecular weight, and yield of organic nitrate under different urban VOC, NO x , and oxidation conditions during SAPHIR-CHANEL campaign

René Dubus, Franz Röhrer, Michelle Färber, Max G. Adam et al.
Atmospheric chemistry and physics
Atmospheric chemistry and aerosols
article

Gas-particle partitioning, molecular weight, and yield of organic nitrate under different urban VOC, NO x , and oxidation conditions during SAPHIR-CHANEL campaign

René Dubus, Franz Röhrer, Michelle Färber, Max G. Adam, Juliane L. Fry, Chelsea E. Stockwell, Achim Grasse, Ralf Tillmann, Rupert Holzinger, Sören R. Zorn, Kelvin H. Bates, Christian Wesolek, Thomas J. Bannan, Matthew Mitchell Coggon, Aristeidis Voliotis, Maarten Krol, Hugh Coe, Matthieu Riva, Hendrik Fuchs, Manjula R. Canagaratna, Mitchell W. Alton, Anna Novelli, Thorsten Hohaus, Eva Y. Pfannerstill, Robert Wegener, Georgios I. Gkatzelis, Gordon B. McFiggans, Farhan Ramadzan Nursanto, Quanfu He, Milan Roska, Annika Zanders, Lu Liu, Yuwei Wang, Boxing Yang, Y N Wu, Sébastien Perrier, Andrea Carolina Marcillo Lara, Sophia van de Wouw, Willem Kroese, Hui Wang, Lukas Kesper, Benjamin Winter, Emily Matthews
article en

Abstract

Abstract. Oxidation of volatile organic compounds (VOCs) involving hydroxyl radicals (OH⚫) and nitrogen oxides (NOx), or nitrate radicals (NO3⚫) forms organic nitrates that undergo gas-particle partitioning, changing the lifetime of nitrogen and their deposition on ecosystems. In urban areas, VOC composition is complex, with contributions from traffic, cooking, volatile chemical products (VCPs), and biogenic emissions. Secondary organic aerosol (SOA) formation from urban VOC mixtures was investigated using chamber experiments during the SAPHIR-CHANEL campaign under realistic VOC-NOx and oxidation conditions. The yield of total organic nitrates is higher for precursor mixtures with a higher percentage of unsaturated VOCs, such as those from traffic and cooking sources (11 %–21 %), compared to VCPs and complex urban emission replicas (2 %–7 %). Enhanced particle-phase partitioning is observed under nighttime oxidation (by NO3⚫) versus daytime oxidation (by OH⚫). Particulate organic nitrates have a higher average molecular weight under nighttime conditions (330 ± 80 g mol−1) than under daytime conditions (250 ± 30 g mol−1) mainly due to a higher dimer fraction. Similarly, the mass fraction of the total organic aerosol that is organic nitrate is 2.6–4.5 times higher under nighttime than daytime conditions, likely due to higher molecular weight and lower temperatures. Although gas-phase organic nitrate composition varies substantially between precursor mixtures, bulk organic nitrate partitioning is generally similar to that of modeled oxidized monoterpene nitrates (10−4–10−2 m3 µg−1 at 18–40 °C). These findings improve understanding of bulk organic nitrate sources and properties in complex urban environments, allowing better simulations of air quality and nitrate deposition.

Atmospheric chemistry and physicsVol. 26(12)
Université Claude Bernard Lyon 1 (FR), TH Köln - University of Applied Sciences (DE), Centre National de la Recherche Scientifique (FR), National Oceanic and Atmospheric Administration (US), Forschungszentrum Jülich (DE), University of Cologne (DE), University of Colorado Boulder (US), Utrecht University (NL), Paul Scherrer Institute (CH), University of Manchester (GB), Aerodyne Research (US), National Centre for Atmospheric Science (GB), Institut de Recherches sur la Catalyse et l'Environnement de Lyon (FR), South China University of Technology (CN), Wageningen University & Research (NL)
National Oceanic and Atmospheric Administration, Horizon 2020 Framework Programme, European Research Council, HORIZON EUROPE European Research Council
Sustainable cities and communities
Openalex Percentile: Top 7%
Atmospheric chemistry and aerosols
DOIOpen Access PDFOpenAlex
AI Navigator

Ask Laika to Summarize, Analyze, and Connect papers live on the map.

Summarize Papers & Methodologies

Extract key findings, datasets, and comparative methods across publications.

Benchmark Rankings & Visual Analytics

Rank top research institutions, authors, funders, topics, and journals by Field-Weighted Citation Impact (FWCI) and paper volume with instant charts.

Connect Distant Disciplines

Bridge topological clusters on the map to find hidden collaborative intersections.