Tropospheric formaldehyde concentration at the Mauna Loa Observatory during the Mauna Loa Observatory Photochemistry Experiment 2

Abstract

The concentration of formaldehyde at Mauna Loa Observatory, Hawaii, was determined during four Mauna Loa Observatory Photochemistry Experiment 2 (MLOPEX 2) measurement intensives between September 1991 and August 1992. The observed diurnal variations, 200-900 parts per trillion by volume (pptv) during daytime and 60-200 pptv during nighttime, resulted mainly from the local air circulation pattern whereby island modified marine boundary layer air prevailed during the day and free tropospheric air dominated during the night. A seasonal variation was also observed; the median/mean values of all data points are: 149/196, 129/149, 143/178, and 181/211 pptv for autumn, winter, spring, and summer intensives, respectively. During nighttime downslope flow periods which brought in free tropospheric air to the measurement site, the formaldehyde concentrations (median/mean) were 122/123, 110/112, 120/125, and 140/137 pptv for autumn, winter, spring, and summer, respectively. This seasonal dependence may be attributable to changes in solar insolation and NO concentrations. A simple box model calculation constrained by the experimentally determined concentrations of CH3OOH yielded a formaldehyde concentration (without/with heterogeneous removal) for free tropospheric air, at 7øC, of 155/140, 125/115,210/195, and 220/205 pptv for autumn, winter, spring and summer, respectively. The calculated values are in good agreement with the measured concentrations for winter (within 27/15%, without/with heterogeneous removal) and fall (within 14/5%), but are significantly higher for spring (75/63%) and summer (57/46%).

Modeling of HCHO and CHOCHO at a semi-rural site in southern China during the PRIDE-PRD2006 campaign

“…The known removal pathways of HCHO in the atmosphere are reaction with OH, photolysis, and dry / wet deposition. Heterogeneous uptake by cloud droplets and aerosols is speculated to be an additional sink of HCHO, which could contribute to the HCHO destruction (Zhou et al, 1996;Tie et al, 2001;Fried et al, 2003a). However, the existence of this process in the lower troposphere is still under discussion.…”

Rapid and Highly Sensitive Determination of Low-Molecular-Weight Carbonyl Compounds in Drinking Water and Natural Water by Preconcentration HPLC with 2,4-Dinitrophenylhydrazine

“…aldehydes (RCOH) and ketones (RCOR′)) in the troposphere are mainly formed by photochemical oxidation process of anthropogenic and biogenic hydrocarbon. [1][2][3] They are also emitted directly by the combustion of fossil fuels and biomass by motor vehicles and industrial processes. 1 LMW carbonyl compounds in the atmosphere are easily dissolved in rain, cloud water and dew.…”

“…The 2,4-dinitrophenylhydrazine (DNPH) derivatization method, in which aldehyde-DNPH derivatives are subsequently separated by high performance liquid chromatography (HPLC) and detected by ultraviolet absorption, has been applied to rain and dew samples. 3,4 A solid phase extraction (SPE) technique has been used in attempts to lower the detection limits for aqueous samples. Kieber and Mopper have reported on the determination of picomolar concentrations of carbonyl compounds in seawater by using a DNPH derivatization/C-18 SPE cartridge with large-volume injection and large-bore column HPLC.…”

“…LMW carbonyl compounds are exchanged directly between the surface water phase and the atmosphere. 3,4 In natural water, LMW carbonyl compounds are produced by the photochemical degradation of dissolved organic matter (DOM). [6][7][8] The LMW carbonyl compounds in natural water are biologically labile, because they are taken up quickly by microorganisms.…”

Formaldehyde over the eastern Mediterranean during MINOS: Comparison of airborne in-situ measurements with 3D-model results

“…In the remote marine boundary layer levels of HCHO exceed 100-200 pptv (Zafirou et al, 1980;Lowe andSchmidt, c European Geosciences Union 2003 1983;Arlander et al, 1990;Heikes, 1992;Harris et al, 1992;Zhou et al, 1996;Mackay et al, 1996;Jacob et al, 1996;Ayers et al, 1997;Jaeglé et al, 2000;Weller et al, 2000;Wagner et al, 2001), and they decrease with increasing altitude in the free troposphere (Arlander et al, 1995;Jacob et al, 1996;Jaeglé et al, 2000;Heikes et al, 2001;Fried et al, 2003). These measurements have been compared to model simulations based on simple steady state expressions (Arlander et al, 1995;Zhou et al, 1996), box models (Liu et al, 1992;Jacob et al, 1996;Ayers et al, 1997;Jaeglé et al, 2000;Weller et al, 2000;Heikes et al, 2001;Frost et al, 2002;Wagner et al, 2002;Fried et al, 2003), two-dimensional (2D) (Lowe and Schmidt, 1983;Arlander et al, 1995), and 3D models (Brasseur et al, 1996;Hauglustaine et al, 1998;von Kuhlmann et al, 2003b).…”