In-situ measurement of reactive hydrocarbons at Hohenpeissenbergwith comprehensive two-dimensional gas chromatography (GC×GC-FID): use in estimating HO andNO3

[摘要] During a field campaign at the Meteorological Observatory Hohenpeissenberg(MOHp) in July 2004, volatile organic compounds (VOCs) were measured usingcomprehensive two-dimensional gas chromatography (GC×GC). Comparisonto routinely made gas chromatography mass spectrometry (GC-MS)measurements showed good agreement for a variety ofanthropogenic and biogenic ambient VOCs ranging in concentration from belowthe detection limit (0.1 pmol mol⁻¹) to 180 pmol mol⁻¹. Pronounceddiurnal cycles were found for both the biogenic and anthropogenic compounds,driven for the most part by the daily rise and fall of the boundary layerover the station. For the reactive compounds (lifetimes <2 days), asignificant, non-zero dependency of the variability on lifetime was found,indicating that chemistry (as opposed to transport alone) was playing a rolein determining the ambient VOC concentrations. The relationship wasexploited using a single-variate analysis to derive a daytime mean value ofHO (5.3±1.4×10₆molecules cm⁻³), which compares wellto that measured at the site, 3.2±2.3×10⁶molecules cm⁻³.The analysis was extended to the night time data to estimate concentrationsfor NO₃ (1.47±0.2×10⁸molecules cm⁻³), which is notmeasured at the site. The feasibility of this approach for environmentsdominated by emissions of short-lived VOCs to estimate ambient levels ofradical species is discussed.

[学科分类] 大气科学