By the same authors

From the same journal

Seasonality of Formic Acid (HCOOH) in London during the ClearfLo Campaign

Research output: Contribution to journalArticlepeer-review


  • Thomas J. Bannan
  • A. Murray Booth
  • Michael Le Breton
  • Asan Bacak
  • Jennifer B. A. Muller
  • Kimberley E. Leather
  • M. Anwar H. Khan
  • James D. Lee
  • Rachel E. Dunmore
  • James R. Hopkins
  • Zoë L. Fleming
  • Leonid Sheps
  • Craig A. Taatjes
  • Dudley E. Shallcross
  • Carl J. Percival


Publication details

JournalJournal of Geophysical Research: Biogeosciences
DateAccepted/In press - 6 Nov 2017
DateE-pub ahead of print (current) - 24 Nov 2017
Early online date24/11/17
Original languageEnglish


Following measurements in the winter of 2012, formic acid (HCOOH) and nitric acid (HNO3) were measured using a chemical ionization mass spectrometer (CIMS) during the Summer Clean Air for London (ClearfLo) campaign in London, 2012. Consequently, the seasonal dependence of formic acid sources could be better understood. A mean formic acid concentration of 1.3 ppb and a maximum of 12.7 ppb was measured which is significantly greater than that measured during the winter campaign (0.63 ppb and 6.7 ppb, respectively). Daily calibrations of formic acid during the summer campaign gave sensitivities of 1.2 ion counts s-1 parts per trillion (ppt) by volume-1 and a limit of detection of 34 ppt. During the summer campaign, there was no correlation between formic acid and anthropogenic emissions such as NOx and CO or peaks associated with the rush hour as was identified in the winter. Rather, peaks in formic acid were observed that correlated with solar irradiance. Analysis using a photochemical trajectory model has been conducted to determine the source of this formic acid. The contribution of formic acid formation through ozonolysis of alkenes is important but the secondary production from biogenic VOCs could be the most dominant source of formic acid at this measurement site during the summer.

Bibliographical note

© 2017, The Authors

    Research areas

  • Air quality, Chemical ionization mass spectrometry, Clean Air for London, Criegee intermediate, Formic acid, Ozonolysis


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