Modification of a commercial cavity ring-down spectroscopy NO{sub 2} detector for enhanced sensitivity

Journal Article · Sun Nov 15 00:00:00 EST 2009 · Review of Scientific Instruments

DOI:https://doi.org/10.1063/1.3244090· OSTI ID:22051075

Castellanos, Patricia; Ehrman, Sheryl H ^[1]; Luke, Winston T; Kelley, Paul ^[2]; Stehr, Jeffrey W; Dickerson, Russell R ^[3]

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1. Department of Chemical and Biomolecular Engineering, University of Maryland, College Park, Maryland 20742 (United States)
2. National Oceanic and Atmospheric Administration, Air Resources Laboratory, SSMC3, Rm. 3316, 1315 East West Hwy., Silver Spring, Maryland 20910 (United States)
3. Department of Atmospheric and Oceanic Science, University of Maryland, College Park, Maryland 20742 (United States)

Nitrogen dioxide (NO{sub 2}) plays a central role in atmospheric chemistry, air pollution, and biogeochemical cycles. Many analytical techniques have been developed to detect NO{sub 2}, but only chemiluminescence-based instruments are commonly, commercially available. There remains a need for a fast, light, and simple method to directly measure NO{sub 2}. In this work we describe the modification and characterization of a small, commercially available cavity ring-down spectroscopy (CRDS) NO{sub 2} detector suitable for surface and aircraft monitoring. A metal oxide scrubber was added to remove NO{sub 2}, and provide a chemical zero, improving the detection limit (3{sigma} of the background noise) from several parts per billion by volume (ppbv) to 0.06 ppbv, integrated over 60 s. Known interferences by water and particles were removed using Nafion tubing and a 1 {mu}m Teflon filter, respectively. A 95% response time of 18{+-}1 s was observed for a step change in concentration. The CRDS detector was run in parallel to an ozone chemiluminescence device with photolytic conversion of NO{sub 2} to NO. The two instruments measured ambient air in suburban Maryland. A least-squares fit to the comparison data resulted a slope of 0.960{+-}0.002 and R of 0.995, showing agreement within experimental uncertainty.

• OSTI ID: 22051075
• Journal Information: Review of Scientific Instruments, Vol. 80, Issue 11; Other Information: (c) 2009 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA); ISSN 0034-6748
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND TECHNOLOGY
AIR POLLUTION
AIRCRAFT
ATMOSPHERIC CHEMISTRY
BACKGROUND NOISE
CHEMILUMINESCENCE
COMPARATIVE EVALUATIONS
INTERFERENCE
LEAST SQUARE FIT
MONITORING
NITROGEN DIOXIDE
OZONE
PARTICLES
SCRUBBERS
SENSORS
SPECTROSCOPY
SURFACES
WATER