Nighttime observation of the HO2 radical by an LIF instrument at Oki island, Japan, and its possible origins

Y. Kanaya*, Y. Sadanaga, J. Matsumoto, U. K. Sharma, J. Hirokawa, Y. Kajii, H. Akimoto

*Corresponding author for this work

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50 Citations (Scopus)


HO2 (hydroperoxy) radical of unexpectedly high concentration around 3 ppt was measured by an instrument based on laser-induced fluorescence with NO addition at Oki island, Japan, on the night of August 9/10, 1998. We confirmed that the interference by atmospheric organic peroxy (RO2) radicals was insignificant and concluded that the measured signal originated from nighttime HO2. Model calculations constrained to ancillary measurements indicated that HO2 and RO2 were produced primarily via the reactions of ozone with olefins, especially those with internal olefins, and that NO3 chemistry was relatively unimportant. HO2 concentration was kept high by nighttime NO (∼10 ppt) via RO2 + NO reactions. Low NO2 (∼150 ppt) slowed NO3 production rate. Thus, the high observed HO2 suggests that the reactions of O3 with olefins are important HOx primary production mechanisms in the relatively clean atmosphere.

Original languageEnglish
Pages (from-to)2179-2182
Number of pages4
JournalGeophysical Research Letters
Issue number14
Publication statusPublished - 1999 Jul 15
Externally publishedYes

ASJC Scopus subject areas

  • Geophysics
  • Earth and Planetary Sciences(all)


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