Photochemical reactions in the urban air: Recent understandings of radical chemistry

Yasuhiro Sadanaga, Jun Matsumoto, Yoshizumi Kajii*

*Corresponding author for this work

Research output: Contribution to journalReview articlepeer-review

51 Citations (Scopus)


In this review article, recent understandings of the urban atmosphere are briefly presented, focusing on NOx (NO and NO2), NO 3 and HOx (OH and HO2), which are the key species for photochemical ozone production in the urban air. For NOx chemistry, relationship between NOx and HOx, and photostationary state (PSS) of the conversion between NO and NO2 are introduced with examples of recent research. Chemistry of nitrate radicals in the nighttime is also introduced. In addition, recent and representative techniques for the measurements of reactive nitrogen species in the troposphere are presented. As for HOx radicals, important formation and loss processes and measurement methods developed recently are introduced. Recent campaign-based observations of HOx radicals in the troposphere are also presented.

Original languageEnglish
Pages (from-to)85-104
Number of pages20
JournalJournal of Photochemistry and Photobiology C: Photochemistry Reviews
Issue number1
Publication statusPublished - 2003 Apr 30
Externally publishedYes


  • Hydroperoxy radical
  • Hydroxyl radical
  • Nitrate radical
  • Nitrogen oxides
  • Photochemical processes
  • Photostationary state
  • Tropospheric ozone
  • Urban air

ASJC Scopus subject areas

  • Catalysis
  • Physical and Theoretical Chemistry
  • Organic Chemistry


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