In-situ measurement of reactive hydrocarbons at Hohenpeissenberg with comprehensive two-dimensional gas chromatography (GC×GC-FID): use in estimating HO and NO3 S. Bartenbach1, J. Williams1, C. Plass-Dülmer2, H. Berresheim2, and J. Lelieveld1 1Max-Planck-Institute for Chemistry, J. J. Becher Weg 27, 55128 Mainz, Germany 2Deutscher Wetterdienst, Meteorologisches Observatorium Hohenpeissenberg, Albin-Schwaiger-Weg 10, 82382 Hohenpeissenberg, Germany
Abstract. During a field campaign at the Meteorological Observatory Hohenpeissenberg
(MOHp) in July 2004, volatile organic compounds (VOCs) were measured using
comprehensive two-dimensional gas chromatography (GC×GC). Comparison
to routinely made gas chromatography mass spectrometry (GC-MS)
measurements showed good agreement for a variety of
anthropogenic and biogenic ambient VOCs ranging in concentration from below
the detection limit (0.1 pmol mol−1) to 180 pmol mol−1. Pronounced
diurnal cycles were found for both the biogenic and anthropogenic compounds,
driven for the most part by the daily rise and fall of the boundary layer
over the station. For the reactive compounds (lifetimes <2 days), a
significant, non-zero dependency of the variability on lifetime was found,
indicating that chemistry (as opposed to transport alone) was playing a role
in determining the ambient VOC concentrations. The relationship was
exploited using a single-variate analysis to derive a daytime mean value of
HO (5.3±1.4×106molecules cm−3), which compares well
to that measured at the site, 3.2±2.3×106molecules cm−3.
The analysis was extended to the night time data to estimate concentrations
for NO3 (1.47±0.2×108molecules cm−3), which is not
measured at the site. The feasibility of this approach for environments
dominated by emissions of short-lived VOCs to estimate ambient levels of
radical species is discussed.
Citation: Bartenbach, S., Williams, J., Plass-Dülmer, C., Berresheim, H., and Lelieveld, J.: In-situ measurement of reactive hydrocarbons at Hohenpeissenberg with comprehensive two-dimensional gas chromatography (GC×GC-FID): use in estimating HO and NO3, Atmos. Chem. Phys., 7, 1-14, doi:10.5194/acp-7-1-2007, 2007.