Observations

Additional In-Situ Measurement Instrumentation and Resources

In addition to the community-requestable instrumentation, ACOM scientists and staff maintain and deploy additional in-situ instrumentation for use in collaborative field programs. These instruments are listed in the table below, along with appropriate contact people.

Instrument

Measurement

Contact Person /

Additional Information

CCD Actinic Flux Spectroradiometer

Spectrally resolved actinic flux and irradiance.

Sam Hall,  halls@ucar.edu

Trace Organic Gas Analyzer (TOGA) fast GC-MSMany VOC compoundsEric Apel, apel@ucar.edu 
One-channel ChemiluminescenceNO, NO2Andy Weinheimer, wein@ucar.edu
PAN Chemical Ionization Mass Spectrometer (CIMS)PAN and analogs Frank Flocke, ffl@ucar.edu
PAN Gas ChromatographPAN and analogs Frank Flocke, ffl@ucar.edu
Proton Transfer Reaction Mass Spectrometer (PTR-MS)

Various VOC compounds

John Ortega, ortega@ucar.edu
Proton Transfer Reaction – Time of Flight - Mass Spectrometer (PTR-TOF-MS)

Various VOC compounds

John Ortega, ortega@ucar.edu 
OH CIMS I

OH, H2SO4, MSA

On loan to UC-Irvine
OH CIMS II

OH, H2SO4, MSA

On loan to CU-Boulder

HO2 CIMS

HO2, RO2On loan to CU-Boulder

 

Laboratory Chamber Facilities

ACOM conducts collaborative research in two laboratory chamber facilities, one focusing on gas-phase processes and the other on gas-phase and aerosol processes.

The gas-phase facility consists of a 2m long, 50 L stainless steel cylindrical chamber, which can be temperature regulated between ˜ 220 – 350 K. The chamber is typically operated in “batch” (static) mode. Gas phase chemistry is initiated with a broad-band UV source, and chemical evolution of chamber contents is monitored by in-situ long-path FT-IR spectroscopy and GC-FID. Sampling of chamber contents for analysis by additional instrumentation (e.g., CIMS, GC, optical) can also be done. Current focus is on oxidation mechanisms of volatile organic compounds, and related chemistry of organic peroxy and alkoxy radicals. Further information can be found here.

The larger chamber (10 m3, 353 ft3) has been newly redesigned.  It is a Teflon atmospheric simulation chamber, for use in studies of gas and aerosol chemistry.  A large chamber of this type provides a number of important advantages, including minimization of wall effects, and enhancement of the ability to work at concentration levels and conditions that mimic those found in nature.  The chamber can be constantly flushed with clean air from a “zero-air generator” that uses  compressed house air, and removes particles, water, NO, NOx ozone, volatile organic compounds and methane prior to an experiment.  There are 4 sample ports on each side of the chamber, which enables researchers to add reactants to the chamber in different locations as well as sample reaction products.  Each of the 4 sides contains 32 “black lights” (total of 128), to allow studies of photochemical processes. Each experiment has a standard set of measurements to control and monitor basic chamber behavior.  This includes measurements of ozone, temperature, particle size distribution, relative humidity, internal pressure, and light intensity.  Other instruments used to monitor reaction products include gas-chromatography (GC) and proton-transfer reaction – mass spectrometry (PTR-MS) for volatile organic compounds, and a number of other chemical ionization mass spectrometers (CIMS) to monitor gas-, cluster-, and particle-phase chemical constituents. 

For further information, and/or to explore collaborative research opportunities contact:

Gas phase work: Geoff Tyndall, tyndall@ucar.edu; John Orlando, orlando@ucar.edu.
Aerosol work: John Ortega, ortega@ucar.edu

UCAR/NCAR Share

                  

                  

ACOM | Atmospheric Chemistry Observations & Modeling