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Rapid cycling of reactive nitrogen in the marine boundary layer


Nitrogen oxides are essential for the formation of secondary atmospheric aerosols and of atmospheric oxidants such as ozone and the hydroxyl radical, which controls the self-cleansing capacity of the atmosphere1. Nitric acid, a major oxidation product of nitrogen oxides, has traditionally been considered to be a permanent sink of nitrogen oxides1. However, model studies predict higher ratios of nitric acid to nitrogen oxides in the troposphere than are observed2,3. A ‘renoxification’ process that recycles nitric acid into nitrogen oxides has been proposed to reconcile observations with model studies2,3,4, but the mechanisms responsible for this process remain uncertain5,6,7,8,9. Here we present data from an aircraft measurement campaign over the North Atlantic Ocean and find evidence for rapid recycling of nitric acid to nitrous acid and nitrogen oxides in the clean marine boundary layer via particulate nitrate photolysis. Laboratory experiments further demonstrate the photolysis of particulate nitrate collected on filters at a rate more than two orders of magnitude greater than that of gaseous nitric acid, with nitrous acid as the main product. Box model calculations based on the Master Chemical Mechanism10,11 suggest that particulate nitrate photolysis mainly sustains the observed levels of nitrous acid and nitrogen oxides at midday under typical marine boundary layer conditions. Given that oceans account for more than 70 per cent of Earth’s surface, we propose that particulate nitrate photolysis could be a substantial tropospheric nitrogen oxide source. Recycling of nitrogen oxides in remote oceanic regions with minimal direct nitrogen oxide emissions could increase the formation of tropospheric oxidants and secondary atmospheric aerosols on a global scale.

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Figure 1: Vertical profiles of HONO, NOx and pNO3 in marine air off the coast of North and South Carolina on 5 July 2013 (RF 14) and 8 July 2013 (RF 16).
Figure 2: Correlation between the required in situ HONO source and the product of the pNO3 concentration and the photolysis frequency of gaseous HNO3.
Figure 3: Simulated diurnal profiles of mixing ratios and budgets for HONO, NOx and total nitrate in the MBL.


  1. Finlayson-Pitts, B. J. & Pitts, J. N., Jr. Chemistry of the Upper and Lower Atmosphere: Theory, Experiments and Applications (Academic, 2000).

  2. Wang, K., Zhang, Y., Nenes, A. & Fountoukis, C. Implementation of dust emission and chemistry into the Community Multiscale Air Quality modeling system and initial application to an Asian dust storm episode. Atmos. Chem. Phys. 12, 10209–10237 (2012).

    CAS  ADS  Article  Google Scholar 

  3. Deng, J., Wang, T., Liu, L. & Jiang, F. Modeling heterogeneous chemical processes on aerosol surface. Particuology 8, 308–318 (2010).

    CAS  Article  Google Scholar 

  4. Kumar, R. et al. Effects of dust aerosols on tropospheric chemistry during a typical pre-monsoon season dust storm in northern India. Atmos. Chem. Phys. 14, 6813–6834 (2014).

    ADS  Article  Google Scholar 

  5. Zhou, X. et al. Nitric acid photolysis on surfaces in low-NO x environments: significant atmospheric implications. Geophys. Res. Lett. 30, 2217 (2003).

    ADS  Google Scholar 

  6. Baergen, A. M. & Donaldson, D. J. Photochemical renoxification of nitric acid on real urban grime. Environ. Sci. Technol. 47, 815–820 (2013).

    CAS  ADS  Article  Google Scholar 

  7. Zhu, C., Xiang, B., Chu, L. T. & Zhu, L. 308 nm photolysis of nitric acid in the gas phase, on aluminum surfaces, and on ice films. J. Phys. Chem. A 114, 2561–2568 (2010).

    CAS  Article  Google Scholar 

  8. Du, J. & Zhu, L. Quantification of the absorption cross sections of surface-adsorbed nitric acid in the 335–365 nm region by Brewster angle cavity ring-down spectroscopy. Chem. Phys. Lett. 511, 213–218 (2011).

    CAS  ADS  Article  Google Scholar 

  9. Zhou, X. et al. Nitric acid photolysis on forest canopy surface as a source for tropospheric nitrous acid. Nature Geosci. 4, 440–443 (2011).

    CAS  ADS  Article  Google Scholar 

  10. Saunders, S. M., Jenkin, M. E., Derwent, R. G. & Pilling, M. J. Protocol for the development of the Master Chemical Mechanism, MCM v3 (part A): tropospheric degradation of non-aromatic volatile organic compounds. Atmos. Chem. Phys. 3, 161–180 (2003).

    CAS  ADS  Article  Google Scholar 

  11. Jenkin, M. E., Saunders, S. M., Wagner, V. & Pilling, M. J. Protocol for the development of the Master Chemical Mechanism, MCM v3 (part B): tropospheric degradation of aromatic volatile organic compounds. Atmos. Chem. Phys. 3, 181–193 (2003).

    CAS  ADS  Article  Google Scholar 

  12. Ren, X. et al. OH, HO2, and OH reactivity during the PMTACS–NY Whiteface Mountain 2002 campaign: observations and model comparison. J. Geophys. Res. 111, D10S03 (2006).

    ADS  Article  Google Scholar 

  13. Czader, B. H. et al. Modeling nitrous acid and its impact on ozone and hydroxyl radical during the Texas Air Quality Study 2006. Atmos. Chem. Phys. 12, 6939–6951 (2012).

    CAS  ADS  Article  Google Scholar 

  14. Lee, J. D. et al. Year-round measurements of nitrogen oxides and ozone in the tropical North Atlantic marine boundary layer. J. Geophys. Res. 114, D21302 (2009).

    ADS  Article  Google Scholar 

  15. Zhang, N. et al. Aircraft measurement of HONO vertical profiles over a forested region. Geophys. Res. Lett. 36, L15820 (2009).

    ADS  Google Scholar 

  16. Li, X. et al. Missing gas-phase source of HONO inferred from Zeppelin measurements in the troposphere. Science 344, 292–296 (2014).

    CAS  ADS  Article  Google Scholar 

  17. Kleffmann, J. Daytime sources of nitrous acid (HONO) in the atmospheric boundary layer. ChemPhysChem 8, 1137–1144 (2007).

    CAS  Article  Google Scholar 

  18. Jankowski, J. J., Kieber, D. J., Mopper, K. & Neale, P. J. Development and intercalibration of ultraviolet solar actinometers. Photochem. Photobiol. 71, 431–440 (2000).

    CAS  Article  Google Scholar 

  19. Ramazan, K. A., Syomin, D. & Finlayson-Pitts, B. J. The photochemical production of HONO during the heterogeneous hydrolysis of NO2 . Phys. Chem. Chem. Phys. 6, 3836–3843 (2004).

    CAS  Article  Google Scholar 

  20. Turekian, V. C., Macko, S. A. & Keene, W. C. Concentrations, isotopic compositions, and sources of size-resolved, particulate organic carbon and oxalate in near-surface marine air at Bermuda during spring. J. Geophys. Res. 108 (D5), 4157 (2003).

    Article  Google Scholar 

  21. Nissenson, P., Knox, C. J. H., Finlayson-Pitts, B. J., Philips, L. F. & Dabdub, D. Enhanced photolysis in aerosols: evidence for important surface effects. Phys. Chem. Chem. Phys. 8, 4700–4710 (2006).

    CAS  Article  Google Scholar 

  22. Richards, N. K. et al. Nitrate ion photolysis in thin water films in the presence of bromide ions. J. Phys. Chem. A 115, 5810–5821 (2011).

    CAS  Article  Google Scholar 

  23. Zhou, X. et al. Snowpack photochemical production of HONO: a major source of OH in the Arctic boundary layer in springtime. Geophys. Res. Lett. 28, 4087–4090 (2001).

    CAS  ADS  Article  Google Scholar 

  24. Val Martin, M., Honrath, R. E., Owen, R. C. & Li, Q. B. Seasonal variation of nitrogen oxides in the central North Atlantic lower free troposphere. J. Geophys. Res. 113, D17307 (2008).

    ADS  Article  Google Scholar 

  25. Helas, G. & Warneck, P. Background NO x mixing ratios in air masses over the North Atlantic Ocean. J. Geophys. Res. 86 (C8), 7283–7290 (1981).

    CAS  ADS  Article  Google Scholar 

  26. Li, S., Matthews, J. & Sinha, A. Atmospheric hydroxyl radical production from electronically excited NO2 and H2O. Science 319, 1657–1660 (2008).

    CAS  ADS  Article  Google Scholar 

  27. Carr, S., Heard, D. E. & Blitz, M. A. Comment on “Atmospheric hydroxyl radical production from electronically excited NO2 and H2O”. Science 324, 336b (2009).

    ADS  Article  Google Scholar 

  28. Ye, C. et al. Comment on “Missing gas-phase source of HONO inferred from Zeppelin measurements in the troposphere”. Science 326, 1657–1659 (2015).

    Google Scholar 

  29. Savarino, J. et al. Isotopic composition of atmospheric nitrate in a tropical marine boundary layer. Proc. Natl Acad. Sci. USA 110, 17668–17673 (2013).

    CAS  ADS  Article  Google Scholar 

  30. Browne, E. C. et al. Observations of total RONO2 over the boreal forest: NO x sinks and HNO3 sources. Atmos. Chem. Phys. 13, 4543–4562 (2013).

    ADS  Article  Google Scholar 

  31. Zhang, N. et al. Measurements of ambient HONO concentrations and vertical HONO flux above a northern Michigan forest canopy. Atmos. Chem. Phys. 12, 8285–8296 (2012).

    CAS  ADS  Article  Google Scholar 

  32. Huang, G., Zhou, X., Deng, G., Qiao, H. & Civerolo, K. Measurements of atmospheric nitrous acid and nitric acid. Atmos. Environ. 36, 2225–2235 (2002).

    CAS  ADS  Article  Google Scholar 

  33. Ridley, B. et al. Florida thunderstorms: a faucet of reactive nitrogen to the upper troposphere. J. Geophys. Res. 109, D17305 (2004).

    ADS  Article  Google Scholar 

  34. Mauldin, R. et al. South Pole Antarctica observations and modeling results: new insights on HOx radical and sulfur chemistry. Atmos. Environ. 44, 572–581 (2010).

    CAS  ADS  Article  Google Scholar 

  35. Hornbrook, R. S. et al. Measurements of tropospheric HO2 and RO2 by oxygen dilution modulation and chemical ionization mass spectrometry. Atmos. Meas. Tech. 4, 735–756 (2011).

    CAS  Article  Google Scholar 

  36. Platt, U. & Stutz, J. Differential Optical Absorption Spectroscopy: Principles and Applications (Springer, 2008).

  37. Shetter, R. E., Cinquini, L., Lefer, B. L., Hall, S. R. & Madronich, S. Comparison of airborne measured and calculated spectral actinic flux and derived photolysis frequencies during the PEM Tropics B mission. J. Geophys. Res. 108 (D2), 8234 (2003).

    Article  Google Scholar 

  38. Flagan, R. C. Electrical mobility methods for sub-micrometer particle characterization. In Aerosol Measurement: Principles, Techniques, and Applications 3rd edn (eds Kulkarni, P. Baron, P. A. & Willeke, K. ), 339–364 (John Wiley & Sons, 2011).

  39. de Gouw, J. & Warneke, C. Measurements of volatile organic compounds in the Earth’s atmosphere using proton-transfer-reaction mass spectrometry. Mass Spectrom. Rev. 26, 223–257 (2007).

    CAS  ADS  Article  Google Scholar 

  40. Hornbrook, R. S. et al. Observations of nonmethane organic compounds during ARCTAS—part 1: Biomass burning emissions and plume enhancements. Atmos. Chem. Phys. 11, 11103–11130 (2011).

    CAS  ADS  Article  Google Scholar 

  41. Gierczak, T., Jimenez, E., Riffault, V., Burkholder, J. B. & Ravishankara, A. R. Thermal decomposition of HO2NO2 (peroxynitric acid, PNA): rate coefficient and determination of the enthalpy of formation. J. Phys. Chem. A 109, 586–596 (2005).

    CAS  Article  Google Scholar 

  42. Cantrell, C. A. et al. Steady state free radical budgets and ozone photochemistry during TOPSE. J. Geophys. Res. 108 (D4), 8361 (2003).

    Article  Google Scholar 

  43. Stohl, A., Forster, C., Frank, A., Seibert, P. & Wotawa, G. The Lagrangian particle dispersion model FLEXPART version 6.2. Atmos. Chem. Phys. 5, 2461–2474 (2005).

    CAS  ADS  Article  Google Scholar 

  44. Stohl, et al. A replacement for simple back trajectory calculations in the interpretation of atmospheric trace substance measurements. Atmos. Environ. 36, 4635–4648 (2002).

    CAS  ADS  Article  Google Scholar 

  45. Zhang, N. Distributions and Sources of HONO in the Rural Troposphere. PhD thesis, (State Univ. New York, 2011).

  46. Sander, S. et al. Chemical Kinetics and Photochemical Data for Use in Atmospheric Studies, Evaluation No. 17 JPL Publication 10-6, (Jet Propulsion Laboratory, 2011).

  47. Weis, D. D. & Ewing, G. E. The reaction of nitrogen dioxide with sea salt aerosol. J. Phys. Chem. A 103, 4865–4873 (1999).

    CAS  Article  Google Scholar 

  48. Joseph, D. M., Ashworth, S. H. & Plane, J. M. C. On the photochemistry of IONO2: absorption cross section (240–370 nm) and photolysis product yields at 248 nm. Phys. Chem. Chem. Phys. 9, 5599–5607 (2007).

    CAS  Article  Google Scholar 

  49. McFiggans, G. et al. A modeling study of iodine chemistry in the marine boundary layer. J. Geophys. Res. 105 (D11), 14371–14385 (2000).

    CAS  ADS  Article  Google Scholar 

  50. Dix, B. et al. Detection of iodine monoxide in the tropical free troposphere. Proc. Natl Acad. Sci. USA 110, 2035–2040 (2013).

    CAS  ADS  Article  Google Scholar 

  51. Zhang, J., Dransfield, T. & Donahue, N. M. On the mechanism for nitrate formation via the peroxy radical + NO reaction. J. Phys. Chem. A 108, 9082–9095 (2004).

    CAS  Article  Google Scholar 

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This research is funded by National Science Foundation (NSF) grants (AGS-1216166, AGS-1215712, and AGS-1216743). We would like to acknowledge operational, technical and scientific support provided by NCAR’s Earth Observing Laboratory, sponsored by the National Science Foundation. Any opinions, findings, conclusions or recommendations expressed in this paper are those of the authors and do not necessarily reflect the views of NSF.

Author information

Authors and Affiliations



Ye, C. and Zhou, X. designed and performed the field and laboratory studies, interpreted the data and write the manuscript with inputs from all the co-authors; Cantrell, C. and Ye, C. performed model simulations.

Corresponding author

Correspondence to Xianliang Zhou.

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The authors declare no competing financial interests.

Additional information

The data are available in our project data archive (

Extended data figures and tables

Extended Data Figure 1 Typical back-trajectories of air masses in the MBL.

a, 5 July 2013; b, 8 July 2013. The air mass circulated within the North Atlantic Ocean under a Bermuda high-pressure system for several days before reaching the measurement locations. On 8 July 2013, the air mass near the coast was also occasionally affected slightly by fresh emissions from the southeast coast of the USA. See ref. 44 for definition of the cluster centroid. The C-130 flight tracks are shown in upper panels by the lines from 33° 39′ N, 77° 42′ W to 32° 11′ N, 77° 41′ W over the North Atlantic Ocean. The altitudes of cluster centroids in the lower panels are in metres above ground level (AGL).

Extended Data Figure 2 Typical diurnal HONO and NOx budgets in the clean MBL calculated by the MCM v3.2.

a, HONO budget; b, NOx budget. ‘HONO photolysis’ and ‘HONO+OH’ represent HONO sinks contributed by HONO photolysis and the gas-phase reactions of HONO with the OH radicals. ‘Nitrate photolysis’, ‘NO+OH’, ‘Excited NO2’, ‘HO2·H2O+NO2’ and ‘NO2 heterogeneous’ represent HONO sources contributed by pNO3 photolysis, the gas-phase reactions of NO with OH, of excited NO2 with H2O and of HO2·H2O with NO2, and the heterogeneous reactions of NO2 on sea-salt aerosol particles, respectively. ‘HOx+NOx’ is the NOx sink contributed by gas-phase reactions of NO2 with OH and of NO with HO2 with a branching ratio of 0.5% (ref. 46). ‘Halogen nitrate’ is the NOx sink contributed by gas-phase reactions of NO2 with primarily BrO and IO (ref. 29). ‘Organic nitrate’ is the NOx sink contributed by reactions of RO2 radicals with NO with an effective branching ratio of 7% (refs 30 and 51). ‘Other sinks’ represents other minor NOx sinks, such as hydrolysis of N2O5. ‘Nitrate photolysis’ is the NOx source contributed by pNO3 photolysis and ‘Other sources’ represents other minor NOx sources, such as photolysis of gaseous HNO3.

Extended Data Figure 3 HONO observation comparison between the UCLA Mini-DOAS instrument and the LPAP instrument within two plumes during the research flight on 20 June 2013.

The Mini-DOAS instrument is a limb-scanning Max-DOAS instrument, and the analysis incorporates the DOAS approach36. The differential slant column densities of HONO were scaled to the differential slant column density analysis of HCHO, which were retrieved in the same spectral interval and multiplied by the in situ HCHO measurements, provided by the TOGA instrument40 to derive HONO mixing ratios. The Mini-DOAS data was obtained along various elevation viewing angles from +45° to −10°. Because of the position of the aircraft relative to the plumes, the plume geometry, and the HCHO scaling, the derived HONO mixing ratios do not depend on elevation viewing angle and this information was therefore omitted from the figure. Error bars (±1 s.d.) accompany each DOAS measurement. DOAS measurements influenced by clouds or aircraft manoeuvres have been removed from the figure. For better visibility negative DOAS values, which were statistically indistinguishable from zero, were set to 0 p.p.t.v. and the error bar was removed. Red error bars show a 20% uncertainty (±1 s.d.) for LPAP HONO results.

Source data

Extended Data Figure 4 Comparison of the xenon arc lamp light spectrum with the solar actinic spectrum.

The xenon light source was filtered by a 4-mm 7740 Pyrex filter, and the solar actinic flux was the 10-min measurement data at 360 m above sea level from 18:55 to 19:05 utc during RF14.

Source data

Extended Data Figure 5 Typical diurnal profiles of HO2+RO2 and OH radicals in the clean MBL as observed and calculated by the MCM v3.2.

a, HO2+RO2 radicals; b, OH radicals. The calculated (Model) and measured (Obs) ratio of HO2 radicals to RO2 radicals (CH3O2 plus higher RO2) is about 1. The error bars represent ±1 s.d. of the model calculations and observations.

Extended Data Table 1 Measurements from the NOMADSS study used in this analysis

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Ye, C., Zhou, X., Pu, D. et al. Rapid cycling of reactive nitrogen in the marine boundary layer. Nature 532, 489–491 (2016).

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