Articles | Volume 19, issue 8
https://doi.org/10.5194/amt-19-2715-2026
https://doi.org/10.5194/amt-19-2715-2026
Research article
 | 
22 Apr 2026
Research article |  | 22 Apr 2026

A novel technique for the humidity dependent calibration of hypoiodous acid (HOI) and iodine (I2)

Lewis Marden, Marvin D. Shaw, Stephen J. Andrews, Maya Zmajkovic, Phil Rund, Becky Alexander, Joel Thornton, Andrew Peters, Peter Karadakov, and Lucy J. Carpenter

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Cited articles

Auzmendi-Murua, I., Castillo, A., and Bozzelli, J.: Mercury Oxidation via Chlorine, Bromine, and Iodine under Atmospheric Conditions: Thermochemistry and Kinetics, J. Phys. Chem. A, 118, 2959–2975, https://doi.org/10.1021/jp412654s, 2014. 
Bitter, M., Ball, S. M., Povey, I. M., and Jones, R. L.: A broadband cavity ringdown spectrometer for in-situ measurements of atmospheric trace gases, Atmos. Chem. Phys., 5, 2547–2560, https://doi.org/10.5194/acp-5-2547-2005, 2005. 
Braban, C. F., Adams, J. W., Rodriguez, D., Cox, R. E., Crowley, J. N., and Schuster, G.: Heterogeneous reactions of HOI, ICl and IBr on sea salt and sea salt proxies, Phys. Chem. Chem. Phys., 9, 3136–3148, https://doi.org/10.1039/b700829e, 2007. 
Breitenlechner, M., Novak, G. A., Neuman, J. A., Rollins, A. W., and Veres, P. R.: A versatile vacuum ultraviolet ion source for reduced pressure bipolar chemical ionization mass spectrometry, Atmos. Meas. Tech., 15, 1159–1169, https://doi.org/10.5194/amt-15-1159-2022, 2022. 
Buys, Z., Brough, N., Huey, L. G., Tanner, D. J., von Glasow, R., and Jones, A. E.: High temporal resolution Br2, BrCl and BrO observations in coastal Antarctica, Atmos. Chem. Phys., 13, 1329–1343, https://doi.org/10.5194/acp-13-1329-2013, 2013. 
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Short summary
Hypoiodous acid (HOI) and molecular iodine (I2) are the dominant precursors of reactive gaseous iodine, which plays an important role in the atmospheric oxidative capacity and in aerosol formation. However, difficulties in the quantification of HOI and I2 mean that very few measurements are available. This work describes a novel calibration method for HOI and reports the detection of HOI and I2 in the marine boundary layer using Br- chemical ionisation mass spectrometry.
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