Difference-frequency-based tunable absorption spectrometer for detection of atmospheric formaldehyde

Lancaster, David G.; Fried, Alan; Wert, B.; Henry, Bruce; Tittel, Frank K.

doi:10.1364/ao.39.004436

Cited by 57 publications

(38 citation statements)

References 16 publications

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“…Inorganic halogen species (Br 2 , Cl 2 , BrO, and HOBr) were measured by chemical ionization mass spectrometry with I − ion chemistry as described in Liao et al (2011Liao et al ( , 2012bLiao et al ( , 2014; O 3 , NO, and NO 2 were measured by chemiluminscence (Ridley et al, 1992;Ryerson et al, 2000). CO was measured using a standard commercial CO analyzer (Thermo Scientific) with infrared absorption detection, and formaldehyde (HCHO) was measured at 1 Hz frequency using a tunable diode laser absorption spectrometer, as described in Fried et al (1997) and Lancaster et al (2000). A large suite of organic compounds was measured in situ by fast GC-MS (Apel et al 2010) and via whole air canister samples with offline GC-MS (Russo et al, 2010).…”

Section: Measurements and Site Descriptionmentioning

confidence: 99%

Bromine atom production and chain propagation during springtime Arctic ozone depletion events in Barrow, Alaska

et al. 2017

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Abstract. Ozone depletion events (ODEs) in the Arctic are primarily controlled by a bromine radical-catalyzed destruction mechanism that depends on the efficient production and recycling of Br atoms. Numerous laboratory and modeling studies have suggested the importance of heterogeneous recycling of Br through HOBr reaction with bromide on saline surfaces. On the other hand, the gas-phase regeneration of bromine atoms through BrO-BrO radical reactions has been assumed to be an efficient, if not dominant, pathway for Br reformation and thus ozone destruction. Indeed, it has been estimated that the rate of ozone depletion is approximately equal to twice the rate of the BrO self-reaction. Here, we use a zero-dimensional, photochemical model, largely constrained to observations of stable atmospheric species from the 2009 Ocean-Atmosphere-Sea Ice-Snowpack (OA-SIS) campaign in Barrow, Alaska, to investigate gas-phase bromine radical propagation and recycling mechanisms of bromine atoms for a 7-day period during late March. This work is a continuation of that presented in and utilizes the same model construct. Here, we use the gas-phase radical chain length as a metric for objectively quantifying the efficiency of gas-phase recycling of bromine atoms. The gas-phase bromine chain length is determined to be quite small, at < 1.5, and highly dependent on ambient O 3 concentrations. Furthermore, we find that Br atom production from photolysis of Br 2 and BrCl, which is predominately emitted from snow and/or aerosol surfaces, can account for between 30 and 90 % of total Br atom production. This analysis suggests that condensed-phase production of bromine is at least as important as, and at times greater than, gas-phase recycling for the occurrence of Arctic ODEs. Therefore, the rate of the BrO self-reaction is not a sufficient estimate for the rate of O 3 depletion.

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Section: Measurements and Site Descriptionmentioning

confidence: 99%

Bromine atom production and chain propagation during springtime Arctic ozone depletion events in Barrow, Alaska

et al. 2017

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“…This method, as used in Barrow, and these observations have been published in Liao et al (2011Liao et al ( , 2012Liao et al ( , 2014. ClO was measured at a height of ∼ 3 m above the snowpack via chemical conversion to a stable, halogenated product followed by online separation and detection by gas chromatography with electron capture detection hyde (HCHO) concentrations were measured at 1 Hz frequency from the fixed tower using a tunable diode laser absorption spectrometer as described in Fried et al (1997) and Lancaster et al (2000). As with the O 3 and NO x measurements, only data at 6 ft were used in this analysis.…”

Section: R Thompson Et Al: Interactions Of Bromine Chlorine Anmentioning

confidence: 99%

Interactions of bromine, chlorine, and iodine photochemistry during ozone depletions in Barrow, Alaska

et al. 2015

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Abstract. The springtime depletion of tropospheric ozone in the Arctic is known to be caused by active halogen photochemistry resulting from halogen atom precursors emitted from snow, ice, or aerosol surfaces. The role of bromine in driving ozone depletion events (ODEs) has been generally accepted, but much less is known about the role of chlorine radicals in ozone depletion chemistry. While the potential impact of iodine in the High Arctic is more uncertain, there have been indications of active iodine chemistry through observed enhancements in filterable iodide, probable detection of tropospheric IO, and recently, observation of snowpack photochemical production of I 2 . Despite decades of research, significant uncertainty remains regarding the chemical mechanisms associated with the bromine-catalyzed depletion of ozone, as well as the complex interactions that occur in the polar boundary layer due to halogen chemistry. To investigate this, we developed a zero-dimensional photochemical model, constrained with measurements from the 2009 OA-SIS field campaign in Barrow, Alaska. We simulated a 7-day period during late March that included a full ozone depletion event lasting 3 days and subsequent ozone recovery to study the interactions of halogen radicals under these different conditions. In addition, the effects of iodine added to our Base Model were investigated. While bromine atoms were primarily responsible for ODEs, chlorine and iodine were found to enhance the depletion rates and iodine was found to be more efficient per atom at depleting ozone than Br. The interaction between chlorine and bromine is complex, as the presence of chlorine can increase the recycling and production of Br atoms, while also increasing reactive bromine sinks under certain conditions. Chlorine chemistry was also found to have significant impacts on both HO 2 and RO 2 , with organic compounds serving as the primary reaction partner for Cl atoms. The results of this work highlight the need for future studies on the production mechanisms of Br 2 and Cl 2 , as well as on the potential impact of iodine in the High Arctic.

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“…However, advances in nonlinear optical materials have allowed a novel optical sensor, based on difference frequency generation (DFG), to be developed for high quality HCHO concentration measurements that do not require cryogenic cooling. Building upon previous efforts [Mine et al, 1997;Lancaster et al, 1998;Richter et al, 1998;Lancaster et al, 1999], the DFG based sensor can now provide real-time detection of atmospheric HCHO with a minimum detectable sensitivity of approximately 0.5 ppbV [Lancaster et al, 2000]. The wavelength selectivity of the DFG method results in less susceptibility to interference from water vapor.…”

Section: Introductionmentioning

confidence: 98%

“…This represents the first field intercomparison of a DFG sensor which promises reliable and robust HCHO quantification using a real-time, autonomous diode laser based sensor [Lancaster et al, 2000], with well established wet chemical trace gas detection techniques. The results of this intercomparison show the DFG precision to be roughly equal to the bias between simultaneous DFG and timeintegrating wet chemical HCHO measurements, validating the use of a DFG sensor for quantitative measurements of HCHO in urban areas.…”

Section: Introductionmentioning

confidence: 99%

Field intercomparison of a novel optical sensor for formaldehyde quantification

Friedfeld

2000

Geophys. Res. Lett.

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Abstract. A one-week in situ intercomparison campaign was completed on the Rice University campus for measuring HCHO using three different techniques, including a novel optical sensor based on difference frequency generation (DFG) operating at room temperature. Two chemical derivatization methods, 2,4-dinitrophenylhydrazine (DNPH) and o-(2,3,4,5,6-pentafluorobenzyl)hydroxylamine (PFBHA), were deployed during the daylight hours for three-to four-hour time-integrated samples. A real-time optical sensor based on laser absorption spectroscopy was operated simultaneously, including nighttime hours. This tunable spectroscopic source based on difference frequency mixing of two fiberamplified diode lasers in periodically poled LiNbO3 (PPLN) was operated at 3.5315 µm (2831.64 cm −1 ) to access a strong HCHO ro-vibrational transition free of interferences from other species. The results showed a bias of -1.7 and -1.2 ppbv and a gross error of 2.6 and 1.5 ppbv for DNPH and PFBHA measurements, respectively, compared with DFG measurements. These results validate the DFG sensor for time-resolved measurements of HCHO in urban areas.

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Difference-frequency-based tunable absorption spectrometer for detection of atmospheric formaldehyde

Cited by 57 publications

References 16 publications

Bromine atom production and chain propagation during springtime Arctic ozone depletion events in Barrow, Alaska

Bromine atom production and chain propagation during springtime Arctic ozone depletion events in Barrow, Alaska

Interactions of bromine, chlorine, and iodine photochemistry during ozone depletions in Barrow, Alaska

Field intercomparison of a novel optical sensor for formaldehyde quantification

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