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Nocturnal loss and daytime source of nitrous acid through reactive uptake and displacement

Nature Geoscience volume 8, pages 5560 (2015) | Download Citation


The nature of daytime sources and night-time sinks of nitrous acid is a key uncertainty in understanding atmospheric oxidation and radical cycling. The accumulation of nitrous acid in the air has been observed to slow down during the night, implying the presence of a night-time sink. In addition, there may be a photochemical source of nitrous acid during the daytime. We used flow tube experiments, measurements of acid displacement efficiencies, and field monitoring of nitrous acid and nitrite concentrations to study the exchange of nitrous acid with soils. Here we show that nitrous acid can react with carbonates or soil at night and subsequently be displaced from soils during the day by air-to-soil transfer of hydrogen chloride and nitric acid, which are generated in the atmosphere photochemically. These processes provide a critical link between the sink of nitrous acid at night and its emission the following day. We conclude that the acid displacement process could contribute a substantial fraction of daytime nitrous acid emissions in numerous environments, including agricultural, urban and vegetated regions, and in any location subject to deposition of soil-derived mineral dust.

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The authors thank N. L. Wagner for experimental assistance and participants of the CalNex and NACHTT field campaigns for support, particularly X. Ren for the measured HONO(g) flux data. T.C.V. and C.J.Y. acknowledge fellowships from the Natural Science and Engineering Research Council of Canada.

Author information

Author notes

    • Trevor C. VandenBoer

    Present address: Department of Earth Science, Memorial University, St John’s, Newfoundland A1B 3X5, Canada

    • Cora J. Young

    Present address: Department of Chemistry, Memorial University, St John’s, Newfoundland A1B 3X7, Canada

    • Milos Z. Markovic

    Present address: Air Quality Research Division, Environment Canada, Toronto, Ontario M3H 5T4, Canada


  1. Department of Chemistry, University of Toronto, Toronto, Ontario M5S 3H6, Canada

    • Trevor C. VandenBoer
    • , Milos Z. Markovic
    •  & Jennifer G. Murphy
  2. Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, Colorado 80309, USA

    • Cora J. Young
    •  & Ranajit K. Talukdar
  3. Chemical Sciences Division, National Oceanic and Atmospheric Administration, Boulder, Colorado 80305, USA

    • Cora J. Young
    • , Ranajit K. Talukdar
    • , Steven S. Brown
    •  & James M. Roberts


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T.C.V. designed and performed the flow tube experiments with contributions from C.J.Y. and R.K.T. T.C.V. and M.Z.M. collected the HONO and particle nitrite observations at CalNex under the guidance of J.G.M. T.C.V. and C.J.Y. prepared this manuscript under the guidance of J.M.R., S.S.B. and J.G.M.

Competing interests

The authors declare no competing financial interests.

Corresponding author

Correspondence to Jennifer G. Murphy.

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