Thermal dissociation cavity attenuated phase shift spectroscopy for continuous measurement of total peroxy and organic nitrates in the clean atmosphere

2016 ◽  
Vol 87 (7) ◽  
pp. 074102 ◽  
Author(s):  
Yasuhiro Sadanaga ◽  
Ryo Takaji ◽  
Ayana Ishiyama ◽  
Kazuo Nakajima ◽  
Atsushi Matsuki ◽  
...  
Keyword(s):  
Phase Shift ◽  
Continuous Measurement ◽  
Thermal Dissociation ◽  
Organic Nitrates ◽  
Clean Atmosphere

scholarly journals Impact of ozone and inlet design on the detection of isoprene-derived organic nitrates by thermal dissociation cavity ring-down spectroscopy (TD-CRDS)

2021 ◽  
Author(s):  
Patrick Dewald ◽  
Raphael Dörich ◽  
Jan Schuladen ◽  
Jos Lelieveld ◽  
John N. Crowley
Keyword(s):  
Thermal Dissociation ◽  
Volume Ratio ◽  
Reaction Chamber ◽  
Organic Nitrates ◽  
Temperature Dependent ◽  
Alkyl Nitrates ◽  
Cavity Ring Down Spectroscopy ◽  
Viable Solution ◽  
Peroxy Nitrates ◽  
Cavity Ring Down

Abstract. We present measurements of isoprene-derived organic nitrates (ISOP-NITs) generated in the reaction of isoprene with the nitrate radical (NO3) in a 1 m3 Teflon reaction chamber. Detection of ISOP-NITs is achieved via their thermal dissociation to nitrogen dioxide (NO2), which is monitored by cavity ring-down spectroscopy (TD-CRDS). Using thermal dissociation inlets (TDIs) made of quartz, the temperature-dependent dissociation profiles (thermograms) of ISOP-NITs measured in the presence of ozone (O3) are broad (350 to 700 K), which contrasts the narrower profiles previously observed for e.g. isopropyl nitrate (iPN) or peroxy acetyl nitrate (PAN) under the same conditions. The shape of the thermograms varied with the TDI’s surface to volume ratio and with material of the inlet walls, providing clear evidence that ozone and quartz surfaces catalyse the dissociation of unsaturated organic nitrates leading to formation of NO2 at temperatures well below 475 K, impeding the separate detection of alkyl nitrates (ANs) and peroxy nitrates (PNs). We present a simple, viable solution to this problem and discuss the potential for interference by the thermolysis of nitric acid (HNO3), nitrous acid (HONO) and O3.

scholarly journals Evaluation of the accuracy of thermal dissociation CRDS and LIF techniques for atmospheric measurement of reactive nitrogen species

2017 ◽  
Vol 10 (5) ◽  
pp. 1911-1926 ◽  
Author(s):  
Caroline C. Womack ◽  
J. Andrew Neuman ◽  
Patrick R. Veres ◽  
Scott J. Eilerman ◽  
Charles A. Brock ◽  
...  
Keyword(s):  
Conversion Efficiency ◽  
Reactive Nitrogen Species ◽  
Thermal Dissociation ◽  
Ambient Air ◽  
Reactive Nitrogen ◽  
Organic Nitrates ◽  
Nitrogen Species ◽  
Operating Characteristics ◽  
Experimental Conditions ◽  
Standard Additions

Abstract. The sum of all reactive nitrogen species (NOy) includes NOx (NO2 + NO) and all of its oxidized forms, and the accurate detection of NOy is critical to understanding atmospheric nitrogen chemistry. Thermal dissociation (TD) inlets, which convert NOy to NO2 followed by NO2 detection, are frequently used in conjunction with techniques such as laser-induced fluorescence (LIF) and cavity ring-down spectroscopy (CRDS) to measure total NOy when set at > 600 °C or speciated NOy when set at intermediate temperatures. We report the conversion efficiency of known amounts of several representative NOy species to NO2 in our TD-CRDS instrument, under a variety of experimental conditions. We find that the conversion efficiency of HNO3 is highly sensitive to the flow rate and the residence time through the TD inlet as well as the presence of other species that may be present during ambient sampling, such as ozone (O3). Conversion of HNO3 at 400 °C, nominally the set point used to selectively convert organic nitrates, can range from 2 to 6 % and may represent an interference in measurement of organic nitrates under some conditions. The conversion efficiency is strongly dependent on the operating characteristics of individual quartz ovens and should be well calibrated prior to use in field sampling. We demonstrate quantitative conversion of both gas-phase N2O5 and particulate ammonium nitrate in the TD inlet at 650 °C, which is the temperature normally used for conversion of HNO3. N2O5 has two thermal dissociation steps, one at low temperature representing dissociation to NO2 and NO3 and one at high temperature representing dissociation of NO3, which produces exclusively NO2 and not NO. We also find a significant interference from partial conversion (5–10 %) of NH3 to NO at 650 °C in the presence of representative (50 ppbv) levels of O3 in dry zero air. Although this interference appears to be suppressed when sampling ambient air, we nevertheless recommend regular characterization of this interference using standard additions of NH3 to TD instruments that convert reactive nitrogen to NO or NO2.

scholarly journals Thermal dissociation cavity ring-down spectrometer (TD-CRDS) for detection of organic nitrates in gas and particle phase

2020 ◽  
Author(s):  
Natalie I. Keehan ◽  
Bellamy Brownwood ◽  
Andrey Marsavin ◽  
Douglas A. Day ◽  
Juliane L. Fry
Keyword(s):  
Thermal Dissociation ◽  
Organic Nitrates ◽  
Particle Phase ◽  
Alkyl Nitrates ◽  
Aerosol Mass Spectrometer ◽  
Particle Measurements ◽  
Aerosol Mass ◽  
Oxidant Concentration ◽  
Concentration Chamber ◽  
Cavity Ring Down

Abstract. A thermal dissociation – cavity ring-down spectrometer (TD-CRDS) was built to measure NO2, peroxy nitrates (PNs), alkyl nitrates (ANs), and HNO3 in the gas and particle phase. The detection limit of the TD-CRDS is 0.66 ppb for ANs, PNs, and HNO3 and 0.48 ppb for NO2. For all four classes of NOy, the time resolution for separate gas and particle measurements is 8 minutes and for total gas + particle measurements is 3 minutes. The accuracy of the TD-CRDS was tested by comparison of NO2 measurements with a chemiluminescent NOx monitor, and aerosol-phase ANs with an Aerosol Mass Spectrometer (AMS). N2O5 causes significant interference in the PNs and ANs channel under high oxidant concentration chamber conditions, and ozone pyrolysis causes a negative interference in the HNO3 channel. Both interferences can be quantified and corrected for, but must be considered when using TD techniques for measurements of organic nitrates. This instrument has been successfully deployed for chamber measurements at widely varying concentrations, as well as ambient measurements of NOy.

scholarly journals A product study of the isoprene+NO<sub>3</sub> reaction

2009 ◽  
Vol 9 (14) ◽  
pp. 4945-4956 ◽  
Author(s):  
A. E. Perring ◽  
A. Wisthaler ◽  
M. Graus ◽  
P. J. Wooldridge ◽  
A. L. Lockwood ◽  
...  
Keyword(s):  
Thermal Dissociation ◽  
Organic Aerosol ◽  
Proton Transfer Reaction ◽  
Product Formation ◽  
Oxidation Products ◽  
Organic Nitrate ◽  
Organic Nitrates ◽  
Isoprene Nitrates ◽  
Additional Constraints ◽  
Product Study

Abstract. Oxidation of isoprene through reaction with NO3 radicals is a significant sink for isoprene that persists after dark. The main products of the reaction are multifunctional nitrates. These nitrates constitute a significant NOx sink in the nocturnal boundary layer and they likely play an important role in formation of secondary organic aerosol. Products of the isoprene+NO3 reaction will, in many locations, be abundant enough to affect nighttime radical chemistry and to persist into daytime where they may represent a source of NOx. Product formation in the isoprene + NO3 reaction was studied in a smog chamber at Purdue University. Isoprene nitrates and other hydrocarbon products were observed using Proton Transfer Reaction-Mass Spectrometry (PTR-MS) and reactive nitrogen products were observed using Thermal Dissociation–Laser Induced Fluorescence (TD-LIF). The organic nitrate yield is found to be 65±12% of which the majority was nitrooxy carbonyls and the combined yield of methacrolein and methyl vinyl ketone (MACR+MVK) is found to be ∼10%. PTR-MS measurements of nitrooxy carbonyls and TD-LIF measurements of total organic nitrates agreed well. The PTR-MS also observed a series of minor oxidation products which were tentatively identified and their yields quantified These other oxidation products are used as additional constraints on the reaction mechanism.

scholarly journals Evaluation of the accuracy of thermal dissociation CRDS and LIF techniques for atmospheric measurement of reactive nitrogen species

2016 ◽  
Author(s):  
Caroline C. Womack ◽  
J. Andrew Neuman ◽  
Patrick R. Veres ◽  
Scott J. Eilerman ◽  
Charles A. Brock ◽  
...  
Keyword(s):  
Conversion Efficiency ◽  
Reactive Nitrogen Species ◽  
Thermal Dissociation ◽  
Ambient Air ◽  
Reactive Nitrogen ◽  
Organic Nitrates ◽  
Nitrogen Species ◽  
Operating Characteristics ◽  
Experimental Conditions ◽  
Standard Additions

Abstract. The sum of all reactive nitrogen species (NOy) includes NOx (NO2 + NO) and all of its oxidized forms, and the accurate detection of NOy is critical to understanding atmospheric nitrogen chemistry. Thermal dissociation (TD) inlets, which convert NOy to NO2 followed by NO2 detection, are frequently used in conjunction with techniques such as laser induced fluorescence (LIF) and cavity ringdown spectroscopy (CRDS) to measure total NOy when set at > 600 °C, or speciated NOy when set at intermediate temperatures. We report the conversion efficiency of known amounts of several representative NOy species to NO2 in our TD-CRDS instrument, under a variety of experimental conditions. We find that the conversion efficiency of HNO3 is highly sensitive to the flow rate and the residence time through the TD inlet, as well as the presence of other species that may be present during ambient sampling, such as ozone (O3). Conversion of HNO3 at 400 °C, nominally the set point used to selectively convert organic nitrates, can range from 2–6 % and may represent an interference in measurement of organic nitrates under some conditions. The conversion efficiency is strongly dependent on the operating characteristics of individual quartz ovens, and should be well calibrated prior to use in field sampling. We demonstrate quantitative conversion of both gas phase N2O5 and particulate ammonium nitrate in the TD inlet at 650 °C, the temperature normally used for conversion of HNO3. N2O5 has two thermal dissociation steps, one at low temperature representing dissociation to NO2 and NO3, and one at high temperature representing dissociation of NO3, which produces exclusively NO2 and not NO. We also find a significant interference from partial conversion (5–10 %) of NH3 to NO at 650 °C in the presence of representative (50 ppbv) levels of O3 in dry zero air. Although this interference appears to be suppressed when sampling ambient air, we nevertheless recommend regular characterization of this interference using standard additions of NH3 to TD instruments that convert reactive nitrogen to NO or NO2.

scholarly journals Thermal dissociation cavity enhanced absorption spectrometer for detecting NO<sub>2</sub>, RO<sub>2</sub>NO<sub>2</sub> and RONO<sub>2</sub> in the atmosphere

2021 ◽  
Author(s):  
Chunmeng Li ◽  
Haichao Wang ◽  
Xiaorui Chen ◽  
Tianyu Zhai ◽  
Shiyi Chen ◽  
...  
Keyword(s):  
Limit Of Detection ◽  
Thermal Dissociation ◽  
Lookup Table ◽  
Organic Nitrates ◽  
Peroxy Radicals ◽  
Alkyl Nitrates ◽  
Mixing Ratios ◽  
Enhanced Absorption ◽  
Field Deployment ◽  
Set Up

Abstract. We developed a thermal dissociation cavity enhanced absorption spectroscopy (TD-CEAS) for the in-situ measurement of NO2, total peroxy nitrates (PNs, RO2NO2), and total alkyl nitrates (ANs, RONO2) in the atmosphere. PNs and ANs are thermally converted to NO2 at the corresponding pyrolysis temperatures and detected by CEAS at 435–455 nm. The instrument samples sequentially from three channels at ambient temperature, 453 K and 653 K, with a cycle of 3 minutes, for measuring NO2, NO2+PNs, and NO2+PNs+ANs, respectively. The absorptions between the three channels are used to derive the mixing ratios of PNs and ANs by the spectral fitting. The limit of detection (LOD) is estimated to be 97 pptv (1σ) at 6 s intervals for NO2. The measurement uncertainty of NO2 is estimated to be 8 %, while the uncertainties of PNs and ANs detection is larger than NO2 due to some chemical interferences in the heating channels, such as the reaction of NO (or NO2) with the peroxy radicals produced by the thermal dissociation of organic nitrates. Based on the laboratory experiments and numerical simulations, we set up a lookup table method to correct these interferences in PNs and ANs channel under various concentrations of ambient organic nitrates, NO, and NO2. Finally, we present the first field deployment and compared it with other instruments during a field campaign in China, the advantage and limitations of this instrument are outlined.

scholarly journals Organic nitrate aerosol formation via NO<sub>3</sub> + BVOC in the Southeastern US

2015 ◽  
Vol 15 (12) ◽  
pp. 16235-16272 ◽  
Author(s):  
B. R. Ayres ◽  
H. M. Allen ◽  
D. C. Draper ◽  
S. S. Brown ◽  
R. J. Wild ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Thermal Dissociation ◽  
Organic Nitrate ◽  
Organic Nitrates ◽  
Ionization Mass ◽  
Aerosol Formation ◽  
Phase Measurements ◽  
Aerosol Mass ◽  
Southeastern Us ◽  
Nitrate Aerosol

Abstract. Gas- and aerosol-phase measurements of oxidants, biogenic volatile organic compounds (BVOC) and organic nitrates made during the Southern Oxidant and Aerosol Study (SOAS campaign, Summer 2013) in central Alabama show that nitrate radical (NO3) reaction with monoterpenes leads to significant secondary aerosol formation. Cumulative losses of NO3 to terpenes are calculated and correlated to gas and aerosol organic nitrate concentrations made during the campaign. Correlation of NO3 radical consumption to organic nitrate aerosol as measured by Aerosol Mass Spectrometry (AMS) and Thermal Dissociation – Laser Induced Fluorescence (TD-LIF) suggests a range of molar yield of aerosol phase monoterpene nitrates of 23–44 %. Compounds observed via chemical ionization mass spectrometry (CIMS) are correlated to predicted nitrate loss to terpenes and show C10H17NO5, likely a hydroperoxy nitrate, is a major nitrate oxidized terpene product being incorporated into aerosols. The comparable isoprene product C5H9NO5 was observed to contribute less than 0.5 % of the total organic nitrate in the aerosol-phase and correlations show that it is principally a gas-phase product from nitrate oxidation of isoprene. Organic nitrates comprise between 30 and 45 % of the NOy budget during SOAS. Inorganic nitrates were also monitored and showed that during incidents of increased coarse-mode mineral dust, HNO3 uptake produced nitrate aerosol mass loading comparable to that of organic nitrate produced via NO3 + BVOC.

scholarly journals Day- and Night-time Formation of Organic Nitrates at a Forested Mountain-site in South West Germany

2016 ◽  
Author(s):  
Nicolas Sobanski ◽  
Jim Thieser ◽  
Jan Schuladen ◽  
Carina Sauvage ◽  
Wei Song ◽  
...  
Keyword(s):  
Thermal Dissociation ◽  
West Germany ◽  
Organic Nitrates ◽  
Lower Yield ◽  
Night Time ◽  
Alkyl Nitrates ◽  
South West ◽  
Peroxy Nitrates ◽  
Kleiner Feldberg

Abstract. We report in-situ measurement of total peroxy-nitrates (ƩPNs) and total alkyl nitrates (ƩANs) in a forested/urban location at the top of the Kleiner Feldberg mountain in South-West Germany. The data, obtained using Thermal Dissociation Cavity Ring Down Spectroscopy (TD-CRDS) in August-September 2011 (PARADE campaign) and July–August 2015 (NOTOMO campaign), represent the first detailed study of ƩPNs and ƩANs over continental Europe. We find that a significant fraction of NOx (up to 75 %) is sequestered as organics nitrates at this site. Futher, we also show that the night-time production of alkyl nitrates by reaction of NO3 with biogenic hydrocarbons is comparable to that from day-time, OH-initiated oxidation pathways. The ƩANs-to-ozone ratio obtained during PARADE was used to derive an approximate, average yield of organic nitrates at noon time from the OH initiated oxidation of VOCs of 7 % at this site in 2011, which is comparable with that obtained from an analysis of VOCs at the site. A much lower yield,

scholarly journals Observations of the diurnal and seasonal trends in nitrogen oxides in the western Sierra Nevada

2006 ◽  
Vol 6 (3) ◽  
pp. 4415-4464 ◽  
Author(s):  
J. G. Murphy ◽  
D. A. Day ◽  
P. A. Cleary ◽  
P. J. Wooldridge ◽  
R. C. Cohen
Keyword(s):  
Nitrogen Oxides ◽  
Sierra Nevada ◽  
Thermal Dissociation ◽  
Ozone Production ◽  
Organic Nitrates ◽  
Research Station ◽  
Small Contribution ◽  
Free Troposphere ◽  
Alkyl Nitrates ◽  
Peroxy Nitrates

Abstract. Observations of speciated nitrogen oxides, namely NO2, total peroxy nitrates (ΣPNs), total alkyl nitrates (ΣANs), and HNO3 by thermal dissociation laser induced fluorescence (TD-LIF), and supporting chemical and meteorological measurements at Big Hill (1860 m), a high elevation site in California's Sierra Nevada Mountains, are described. From May through October, terrain-driven winds in the region routinely bring air from Sacramento, 100 km southwest of the site, upslope over oak and pine forests to Big Hill during the day, while at night, the site often samples clean, dry air characteristic of the free troposphere. Winter differs mainly in that the meteorology does not favour the buildup of Sacramento's pollution over the Sierra Nevada range, and the urban-influenced air that is seen has been less affected by biogenic VOC emissions, resulting in longer lifetime for NO2 and a predominance of the inorganic forms of nitrogen oxides. Summertime observations at Big Hill can be compared with those from Granite Bay, a Sacramento suburb, and from the University of California's Blodgett Forest Research Station to examine the evolution of nitrogen oxides and ozone within the urban plume. Nitrogen oxide radicals (NO and NO2), which dominate total nitrogen oxides (NOy) at Granite Bay, are rapidly converted into HNO3, ΣPNs, and ΣANs, such that these compounds contribute 29, 30, and 21% respectively to the NOy budget in the plume at Big Hill. Nevertheless, the decreasing concentrations of NO2 as the plume is advected to Big Hill lead to decreases in the production rate of HNO3 and ozone. The data also demonstrate the role that temperature plays in sequestering NO2 into peroxy nitrates, effectively decreasing the rate of ozone production. The important contribution of ΣANs to NOy in the region suggests that they should be considered with regards to export of NOy from the boundary layer. Nocturnal observations of airmasses characteristic of the free troposphere showed lower NOy concentrations, which were dominated by HNO3 with a relatively small contribution from the organic nitrates.

scholarly journals Observations of the diurnal and seasonal trends in nitrogen oxides in the western Sierra Nevada

2006 ◽  
Vol 6 (12) ◽  
pp. 5321-5338 ◽  
Author(s):  
J. G. Murphy ◽  
D. A. Day ◽  
P. A. Cleary ◽  
P. J. Wooldridge ◽  
R. C. Cohen
Keyword(s):  
Nitrogen Oxides ◽  
Sierra Nevada ◽  
Thermal Dissociation ◽  
Ozone Production ◽  
Organic Nitrates ◽  
Research Station ◽  
Small Contribution ◽  
Free Troposphere ◽  
Alkyl Nitrates ◽  
Peroxy Nitrates

Abstract. Observations of speciated nitrogen oxides, namely NO2, total peroxy nitrates (ΣPNs), total alkyl nitrates (ΣANs), and HNO3 by thermal dissociation laser induced fluorescence (TD-LIF), and supporting chemical and meteorological measurements at Big Hill (1860 m), a high elevation site in California's Sierra Nevada Mountains, are described. From May through October, terrain-driven winds in the region routinely bring air from Sacramento, 100 km southwest of the site, upslope over oak and pine forests to Big Hill during the day, while at night, the site often samples clean, dry air characteristic of the free troposphere. Winter differs mainly in that the meteorology does not favour the buildup of Sacramento's pollution over the Sierra Nevada range, and the urban-influenced air that is seen has been less affected by biogenic VOC emissions, resulting in longer lifetime for NO2 and a predominance of the inorganic forms of nitrogen oxides. Summertime observations at Big Hill can be compared with those from Granite Bay, a Sacramento suburb, and from the University of California's Blodgett Forest Research Station to examine the evolution of nitrogen oxides and ozone within the urban plume. Nitrogen oxide radicals (NO and NO2), which dominate total nitrogen oxides (NOy) at Granite Bay, are rapidly converted into HNO3, ΣPNs, and ΣANs, such that these compounds contribute 29, 30, and 21% respectively to the NOy budget in the plume at Big Hill. Nevertheless, the decreasing concentrations of NO2 as the plume is advected to Big Hill lead to decreases in the production rate of HNO3 and ozone. The data also demonstrate the role that temperature plays in sequestering NO2 into peroxy nitrates, effectively decreasing the rate of ozone production. The important contribution of ΣANs to NOy in the region suggests that they should be considered with regards to export of NOy from the boundary layer. Nocturnal observations of airmasses characteristic of the free troposphere showed lower NOy concentrations, which were dominated by HNO3 with a relatively small contribution from the organic nitrates.

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