scholarly journals A five-channel cavity ring-down spectrometer for the detection of NO<sub>2</sub>, NO<sub>3</sub>, N<sub>2</sub>O<sub>5</sub>, total peroxy nitrates and total alkyl nitrates

2016 ◽  
Vol 9 (10) ◽  
pp. 5103-5118 ◽  
Author(s):  
Nicolas Sobanski ◽  
Jan Schuladen ◽  
Gerhard Schuster ◽  
Jos Lelieveld ◽  
John N. Crowley
Keyword(s):  
Thermal Decomposition ◽  
Thermal Dissociation ◽  
Organic Radical ◽  
Alkyl Nitrates ◽  
Mixing Ratios ◽  
Instrument Construction ◽  
Peroxy Nitrates ◽  
Field Deployment ◽  
And Performance ◽  
Cavity Ring Down

Abstract. We report the characteristics and performance of a newly developed five-channel cavity ring-down spectrometer to detect NO3, N2O5, NO2, total peroxy nitrates (ΣPNs) and total alkyl nitrates (ΣANs). NO3 and NO2 are detected directly at 662 and 405 nm, respectively. N2O5 is measured as NO3 after thermal decomposition at 383 K. PNs and ANs are detected as NO2 after thermal decomposition at 448 and 648 K. We describe details of the instrument construction and operation as well as the results of extensive laboratory experiments that quantify the chemical and optical interferences that lead to biases in the measured mixing ratios, in particular involving the reactions of organic radical fragments following thermal dissociation of PNs and ANs. Finally, we present data obtained during the first field deployment of the instrument in July 2015.

scholarly journals A 5-channel cavity ring-down spectrometer for the detection of NO<sub>2</sub>, NO<sub>3</sub>, N<sub>2</sub>O<sub>5</sub>, total peroxy nitrates and total alkyl nitrates

2016 ◽  
Author(s):  
N. Sobanski ◽  
J. Schuladen ◽  
G. Schuster ◽  
J. Lelieveld ◽  
J. Crowley
Keyword(s):  
Thermal Decomposition ◽  
Thermal Dissociation ◽  
Organic Radical ◽  
Alkyl Nitrates ◽  
Mixing Ratios ◽  
Instrument Construction ◽  
Peroxy Nitrates ◽  
Field Deployment ◽  
And Performance ◽  
Cavity Ring Down

Abstract. We report the characteristics and performance of a newly developed 5-channel cavity-ring-down spectrometer to detect NO3, N2O5, NO2, total peroxy nitrates and total alkyl nitrates. NO3 and NO2 are detected directly at 662 nm and 405 nm, respectively. N2O5 is measured as NO3 after thermal decomposition at 383 K. PNs and ANs are detected as NO2 after thermal decomposition at 448 K and 648 K. We describe details of the instrument construction and operation as well as the results of extensive laboratory experiments that quantify the chemical and optical interferences that lead to biases in the measured mixing ratios, in particular involving the reactions of organic radical fragments following thermal dissociation of PNs and ANs. Finally, we present data obtained during the first field deployment of the instrument in July 2015.

scholarly journals A two-channel thermal dissociation cavity ring-down spectrometer for the detection of ambient NO<sub>2</sub>, RO<sub>2</sub>NO<sub>2</sub> and RONO<sub>2</sub>

2016 ◽  
Vol 9 (2) ◽  
pp. 553-576 ◽  
Author(s):  
J. Thieser ◽  
G. Schuster ◽  
J. Schuladen ◽  
G. J. Phillips ◽  
A. Reiffs ◽  
...  
Keyword(s):  
Laboratory Experiments ◽  
Thermal Dissociation ◽  
Organic Radicals ◽  
Peroxy Radicals ◽  
Correction Factors ◽  
Alkyl Nitrates ◽  
Mixing Ratios ◽  
Peroxy Nitrates ◽  
Reference Samples ◽  
Cavity Ring Down

Abstract. We describe a thermal dissociation cavity ring-down spectrometer (TD-CRDS) for measurement of ambient NO2, total peroxy nitrates (ΣPNs) and total alkyl nitrates (ΣANs). The spectrometer has two separate cavities operating at  ∼  405.2 and 408.5 nm. One cavity (reference) samples NO2 continuously from an inlet at ambient temperature, the other samples sequentially from an inlet at 473 K in which PNs are converted to NO2 or from an inlet at 723 K in which both PNs and ANs are converted to NO2, difference signals being used to derive mixing ratios of ΣPNs and ΣANs. We describe an extensive set of laboratory experiments and numerical simulations to characterise the fate of organic radicals in the hot inlets and cavity and derive correction factors to account for the bias resulting from the interaction of peroxy radicals with ambient NO and NO2. Finally, we present the first measurements and comparison with other instruments during a field campaign, outline the limitations of the present instrument and provide an outlook for future improvements.

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

2021 ◽  
Vol 14 (6) ◽  
pp. 4033-4051
Author(s):  
Chunmeng Li ◽  
Haichao Wang ◽  
Xiaorui Chen ◽  
Tianyu Zhai ◽  
Shiyi Chen ◽  
...  
Keyword(s):  
Thermal Dissociation ◽  
Lookup Table ◽  
Organic Nitrates ◽  
Peroxy Radicals ◽  
Alkyl Nitrates ◽  
Mixing Ratios ◽  
Enhanced Absorption ◽  
Cavity Enhanced Absorption Spectroscopy ◽  
Peroxy Nitrates ◽  
Field Deployment

Abstract. We developed 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 were thermally converted to NO2 at the corresponding pyrolytic temperatures and detected by CEAS at 435–455 nm. The instrument sampled sequentially from three channels at ambient temperature, 453 and 653 K, with a cycle of 3 min, to measure NO2, NO2+ PNs, and NO2+ PNs + ANs. The absorptions between the three channels were used to derive the mixing ratios of PNs and ANs by spectral fitting. The detection limit (LOD, 1σ) for retrieving NO2 was 97 parts per trillion by volume (pptv) in 6 s. The measurement uncertainty of NO2 was 9 %, while the uncertainties of PN and AN detection were larger than those of NO2 due to chemical interferences that occurred in the heated channels, such as the reaction of NO (or NO2) with the peroxy radicals produced by the thermal dissociation of organic nitrates. Based on laboratory experiments and numerical simulations, we created a lookup table method to correct these interferences in PN and AN channels under various ambient organic nitrates, NO, and NO2. Finally, we present the first field deployment and compare it with other instruments during a field campaign in China. The advantages and limitations of this instrument are outlined.

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 A two-channel, Thermal Dissociation Cavity-Ringdown Spectrometer for the detection of ambient NO<sub>2</sub>, RO<sub>2</sub>NO<sub>2</sub> and RONO<sub>2</sub>

2015 ◽  
Vol 8 (11) ◽  
pp. 11533-11596
Author(s):  
J. Thieser ◽  
G. Schuster ◽  
G. J. Phillips ◽  
A. Reiffs ◽  
U. Parchatka ◽  
...  
Keyword(s):  
Laboratory Experiments ◽  
Thermal Dissociation ◽  
Organic Radicals ◽  
Peroxy Radicals ◽  
Correction Factors ◽  
Alkyl Nitrates ◽  
Cavity Ringdown ◽  
Mixing Ratios ◽  
Peroxy Nitrates ◽  
Reference Samples

Abstract. We describe a Thermal Dissociation Cavity-Ring-Down Spectrometer (TD-CRDS) for measurement of ambient NO2, total peroxy nitrates (ΣPNs) and total alkyl nitrates (ΣANs). The spectrometer has two separate cavities operating at ~ 405.2 and 408.5 nm, one cavity (reference) samples NO2 continuously from an inlet at ambient temperature, the other samples sequentially from an inlet at 473 K in which PNs are converted to NO2 or from an inlet at 723 K in which both PNs and ANs are converted to NO2, difference signals being used to derive mixing ratios of ΣPNs and ΣANs. We describe an extensive set of laboratory experiments and numerical simulations to characterise the fate of organic radicals in the hot inlets and cavity and derive correction factors to account for the bias resulting from interaction of peroxy radicals with ambient NO and NO2. Finally, we present the first measurements and comparison with other instruments during a field campaign, outline the limitations of the present instrument and provide an outlook for future improvements.

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 A thermal-dissociation–cavity ring-down spectrometer (TD-CRDS) for the detection of organic nitrates in gas and particle phases

2020 ◽  
Vol 13 (11) ◽  
pp. 6255-6269
Author(s):  
Natalie I. Keehan ◽  
Bellamy Brownwood ◽  
Andrey Marsavin ◽  
Douglas A. Day ◽  
Juliane L. Fry
Keyword(s):  
Thermal Dissociation ◽  
Organic Nitrates ◽  
Alkyl Nitrates ◽  
Aerosol Mass Spectrometer ◽  
Particle Measurements ◽  
Aerosol Mass ◽  
Oxidant Concentration ◽  
Peroxy Nitrates ◽  
Concentration Chamber ◽  
Cavity Ring Down

Abstract. A thermal-dissociation–cavity ring-down spectrometer (TD-CRDS) was developed to measure NO2, peroxy nitrates (PNs), alkyl nitrates (ANs), and HNO3 in the gas and particle phase, built using a commercial Los Gatos Research NO2 analyzer. 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 min, and for total gas + particle measurements it is 3 min. 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 PN and AN 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 Impact of ozone and inlet design on the quantification of isoprene-derived organic nitrates by thermal dissociation cavity ring-down spectroscopy (TD-CRDS)

2021 ◽  
Vol 14 (8) ◽  
pp. 5501-5519
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 ◽  
Reactive Material ◽  
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, for example, 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). The use of a TDI consisting of a non-reactive material suppresses the conversion of isoprene-derived ANs at 473 K, thus allowing selective detection of PNs. The potential for interference by the thermolysis of nitric acid (HNO3), nitrous acid (HONO) and O3 is assessed.

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.

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