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

TY - JOUR

T1 - Seasonality of Formic Acid (HCOOH) in London during the ClearfLo Campaign

AU - Bannan, Thomas J.

AU - Murray Booth, A.

AU - Le Breton, Michael

AU - Bacak, Asan

AU - Muller, Jennifer B. A.

AU - Leather, Kimberley E.

AU - Khan, M. Anwar H.

AU - Lee, James D.

AU - Dunmore, Rachel E.

AU - Hopkins, James R.

AU - Fleming, Zoë L.

AU - Sheps, Leonid

AU - Taatjes, Craig A.

AU - Shallcross, Dudley E.

AU - Percival, Carl J.

N1 - © 2017, The Authors

PY - 2017/11/24

Y1 - 2017/11/24

N2 - 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.

AB - 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.

KW - Air quality

KW - Chemical ionization mass spectrometry

KW - Clean Air for London

KW - Criegee intermediate

KW - Formic acid

KW - Ozonolysis

UR - http://www.scopus.com/inward/record.url?scp=85034966765&partnerID=8YFLogxK

U2 - 10.1002/2017JD027064

DO - 10.1002/2017JD027064

M3 - Article

AN - SCOPUS:85034966765

SN - 2169-8953

JO - Journal of Geophysical Research: Biogeosciences

JF - Journal of Geophysical Research: Biogeosciences

ER -