Car-Borne Measurements of Atmospheric NO2 by a Compact Broadband Cavity Enhanced Absorption Spectrometer

2021 ◽  
Author(s):  
L. Ling ◽  
Y. Huang ◽  
A. Li ◽  
R. Hu ◽  
P. Xie
Keyword(s):  
Enhanced Absorption ◽  
Absorption Spectrometer

scholarly journals A broadband cavity enhanced absorption spectrometer for aircraft measurements of glyoxal, methylglyoxal, nitrous acid, nitrogen dioxide, and water vapor

2016 ◽  
Vol 9 (2) ◽  
pp. 423-440 ◽  
Author(s):  
K.-E. Min ◽  
R. A. Washenfelder ◽  
W. P. Dubé ◽  
A. O. Langford ◽  
P. M. Edwards ◽  
...  
Keyword(s):  
Nitrogen Dioxide ◽  
Cross Sections ◽  
Nitrous Acid ◽  
Aircraft Measurements ◽  
Charge Coupled Device ◽  
Light Emitting ◽  
Enhanced Absorption ◽  
Field Campaigns ◽  
A Charge ◽  
Absorption Spectrometer

Abstract. We describe a two-channel broadband cavity enhanced absorption spectrometer (BBCEAS) for aircraft measurements of glyoxal (CHOCHO), methylglyoxal (CH3COCHO), nitrous acid (HONO), nitrogen dioxide (NO2), and water (H2O). The instrument spans 361–389 and 438–468 nm, using two light-emitting diodes (LEDs) and a single grating spectrometer with a charge-coupled device (CCD) detector. Robust performance is achieved using a custom optical mounting system, high-power LEDs with electronic on/off modulation, high-reflectivity cavity mirrors, and materials that minimize analyte surface losses. We have successfully deployed this instrument during two aircraft and two ground-based field campaigns to date. The demonstrated precision (2σ) for retrievals of CHOCHO, HONO and NO2 are 34, 350, and 80 parts per trillion (pptv) in 5 s. The accuracy is 5.8, 9.0, and 5.0 %, limited mainly by the available absorption cross sections.

An off-axis cavity-enhanced absorption spectrometer at 1605 nm for the 12CO2/13CO2 measurement

2006 ◽  
Vol 85 (2-3) ◽  
pp. 413-420 ◽  
Author(s):  
V.L. Kasyutich ◽  
P.A. Martin ◽  
R.J. Holdsworth
Keyword(s):  
Enhanced Absorption ◽  
Absorption Spectrometer

scholarly journals Measurement of glyoxal using an incoherent broadband cavity enhanced absorption spectrometer

2008 ◽  
Vol 8 (4) ◽  
pp. 16517-16553 ◽  
Author(s):  
R. A. Washenfelder ◽  
A. O. Langford ◽  
H. Fuchs ◽  
S. S. Brown
Keyword(s):  
Rayleigh Scattering ◽  
Optical Cavity ◽  
Field Measurements ◽  
Array Detector ◽  
Enhanced Absorption ◽  
Minimum Detectable Absorption ◽  
Wide Range ◽  
Path Lengths ◽  
A Charge ◽  
Absorption Spectrometer

Abstract. We describe an instrument for simultaneous measurements of glyoxal (CHOCHO) and nitrogen dioxide (NO2) using cavity enhanced absorption spectroscopy with a broadband light source. The output of a Xenon arc lamp is coupled into a 1 m optical cavity, and the spectrum of light exiting the cavity is recorded by a grating spectrometer with a charge-coupled device (CCD) array detector. The mirror reflectivity and effective path lengths are determined from the known Rayleigh scattering of He and dry zero air (N2+O2). Least-squares fitting, using published reference spectra, allow the simultaneous retrieval of CHOCHO, NO2, O4, and H2O in the 441 to 469 nm spectral range. For a 1-min sampling time, the minimum detectable absorption is 4×10−10 cm−1, and the precision (±1σ) on signal for measurements of CHOCHO and NO2 is 29 pptv and 20 pptv, respectively. We directly compare the incoherent broadband cavity enhanced absorption spectrometer to 404 and 532 nm cavity ringdown instruments for CHOCHO and NO2 detection, and find linear agreement over a wide range of concentrations. The instrument has been tested in the laboratory with both synthetic and real air samples, and the demonstrated sensitivity and specificity suggest a strong potential for field measurements of both CHOCHO and NO2.

scholarly journals Light extinction by secondary organic aerosol: an intercomparison of three broadband cavity spectrometers

2013 ◽  
Vol 6 (11) ◽  
pp. 3115-3130 ◽  
Author(s):  
R. M. Varma ◽  
S. M. Ball ◽  
T. Brauers ◽  
H.-P. Dorn ◽  
U. Heitmann ◽  
...  
Keyword(s):  
Refractive Index ◽  
Optical Cavity ◽  
Light Extinction ◽  
Organic Nitrates ◽  
Aerosol Extinction ◽  
Particle Phase ◽  
Extinction Coefficients ◽  
Enhanced Absorption ◽  
Intercomparison Study ◽  
Absorption Spectrometer

Abstract. Broadband optical cavity spectrometers are maturing as a technology for trace-gas detection, but only recently have they been used to retrieve the extinction coefficient of aerosols. Sensitive broadband extinction measurements allow explicit separation of gas and particle phase spectral contributions, as well as continuous spectral measurements of aerosol extinction in favourable cases. In this work, we report an intercomparison study of the aerosol extinction coefficients measured by three such instruments: a broadband cavity ring-down spectrometer (BBCRDS), a cavity-enhanced differential optical absorption spectrometer (CE-DOAS), and an incoherent broadband cavity-enhanced absorption spectrometer (IBBCEAS). Experiments were carried out in the SAPHIR atmospheric simulation chamber as part of the NO3Comp campaign to compare the measurement capabilities of NO3 and N2O5 instrumentation. Aerosol extinction coefficients between 655 and 690 nm are reported for secondary organic aerosols (SOA) formed by the NO3 oxidation of β-pinene under dry and humid conditions. Despite different measurement approaches and spectral analysis procedures, the three instruments retrieved aerosol extinction coefficients that were in close agreement. The refractive index of SOA formed from the β-pinene + NO3 reaction was 1.61, and was not measurably affected by the chamber humidity or by aging of the aerosol over several hours. This refractive index is significantly larger than SOA refractive indices observed in other studies of OH and ozone-initiated terpene oxidations, and may be caused by the large proportion of organic nitrates in the particle phase. In an experiment involving ammonium sulfate particles, the aerosol extinction coefficients as measured by IBBCEAS were found to be in reasonable agreement with those calculated using the Mie theory. The results of the study demonstrate the potential of broadband cavity spectrometers for determining the optical properties of aerosols.

Demonstration of a Mid-Infrared Cavity Enhanced Absorption Spectrometer for Breath Acetone Detection

2012 ◽  
Vol 85 (2) ◽  
pp. 846-850 ◽  
Author(s):  
Luca Ciaffoni ◽  
Gus Hancock ◽  
Jeremy J. Harrison ◽  
Jean-Pierre H. van Helden ◽  
Cathryn E. Langley ◽  
...  
Keyword(s):  
Mid Infrared ◽  
Enhanced Absorption ◽  
Breath Acetone ◽  
Acetone Detection ◽  
Absorption Spectrometer
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