An improved dual channel PERCA instrument for atmospheric measurements of peroxy radicals.

This paper describes a new dual-channel PEroxy RadiCal Amplification (PERCA) instrument, which has been designed to improve the time resolution and signal to noise and to reduce the interference caused by variations in ambient ozone concentrations. The instrument was run at the Weybourne Atmospheric Observatory (WAO), North Norfolk, during WAOWEX (Weybourne Atmospheric Observatory Winter Experiment) in January/February 2002 and INSPECTRO (Influence of clouds on the spectral actinic flux in the lower troposphere) in September 2002. The performance of the instrument is assessed and compared to that of a single channel instrument. In particular, it is shown how the precision is greatly improved in fluctuating background ozone conditions. In addition the improved time response of the instrument allows changes in peroxy radical concentrations to be related to rapid changes in nitric oxide concentrations and the ozone photolysis frequency, j(O(1)D).

[1]  Aircraft-borne measurements of peroxy radicals by Chemical Conversion/Ion Molecule Reaction Mass Spectrometry: Calibration, diagnostics, and results , 1999 .

[2]  D. Hastie,et al.  Optimized Operation and Calibration Procedures for Radical Amplifier-Type Detectors , 2000 .

[3]  D. Jacob,et al.  Peroxy radical behavior during the Transport and Chemical Evolution over the Pacific (TRACE-P) campaign as measured aboard the NASA P-3B aircraft , 2003 .

[4]  James Lee,et al.  Production of peroxy radicals at night via reactions of ozone and the nitrate radical in the marine boundary layer , 2001 .

[5]  P. Monks,et al.  Seasonal variation of peroxy radicals in the lower free troposphere based on observations from the FREE Tropospheric EXperiments in the Swiss Alps , 2003 .

[6]  A. Weinheimer,et al.  Airborne in‐situ OH and HO2 observations in the cloud‐free troposphere and lower stratosphere during SUCCESS , 1998 .

[7]  A. Jefferson,et al.  Selected ion chemical ionization mass spectrometric measurement of OH , 1997 .

[8]  Claire E Reeves,et al.  Measurements of peroxides and what they tell us. , 2003, Chemical reviews.

[9]  M. Pilling,et al.  Measurement of OH and HO2 in the troposphere. , 2003, Chemical reviews.

[10]  J. Burrows,et al.  Investigation of The Effect of Water Complexes In The Determination of Peroxy Radical Ambient Concentrations , 2003 .

[11]  P. Monks,et al.  A seasonal comparison of ozone photochemistry in the remote marine boundary layer , 2000 .

[12]  Michael J. Pilling,et al.  Implementation and initial deployment of a fieldinstrument for measurement of OH and HO2 in thetroposphere by laser-induced fluorescence , 1997 .

[13]  Donald H. Stedman,et al.  Measurement of atmospheric peroxy radicals by chemical amplification , 1984 .

[14]  J. Burrows,et al.  Marine boundary layer peroxy radical chemistry during the AEROSOLS99 campaign: Measurements and analysis , 2001 .

[15]  Paul S. Monks,et al.  A Seasonal Comparison of the Ozone Photochemistry in Clean and Polluted Air Masses at Mace Head, Ireland , 2002 .

[16]  P. Monks,et al.  Night-time peroxy radical chemistry in the remote marine boundary layer over the Southern Ocean , 1996 .

[17]  K. Clemitshaw,et al.  Simultaneous observations of nitrate and peroxy radicals in the marine boundary layer , 1997 .

[18]  P. Monks,et al.  On the relationship of HO2 + RO2 with j(O1 D) during the Free Tropospheric Experiment (FREETEX '96) at the Jungfraujoch Observatory(3580 m above sea level) in the Swiss Alps , 1999 .

[19]  John P. Burrows,et al.  Peroxy radical and related trace gas measurements in the boundary layer above the Atlantic Ocean , 2001 .

[20]  B. Anderson,et al.  An Assessment of HOx Chemistry in the Tropical Pacific Boundary Layer: Comparison of Model Simulations with Observations Recorded during PEM Tropics A , 2001 .

[21]  D. Tanner,et al.  Peroxy radical concentrations measured and calculated from trace gas measurements in the Mauna Loa Observatory Photochemistry Experiment 2 , 1996 .

[22]  Paul S Monks,et al.  Gas-phase radical chemistry in the troposphere. , 2005, Chemical Society reviews.

[23]  Yutaka Kondo,et al.  Photochemistry of HO x in the upper troposphere at northern midlatitudes , 2000 .

[24]  K. Clemitshaw,et al.  Relationships between ozone photolysis rates and peroxy radical concentrations in clean marine air over the Southern Ocean , 1997 .

[25]  Bruce E. Anderson,et al.  Observations of HO x and its relationship with NO x in the upper troposphere during SONEX , 2000 .

[26]  L. Cárdenas,et al.  Studies of Oxidant Production at the Weybourne Atmospheric Observatory in Summer and Winter Conditions , 1999 .

[27]  K. Clemitshaw,et al.  A calibrated peroxy radical chemical amplifier for ground-based tropospheric measurements , 1997 .

[28]  S. Wofsy,et al.  Tropospheric chemistry: A global perspective , 1981 .

[29]  Paul S. Monks,et al.  A study of peroxy radicals and ozone photochemistry at coastal sites in the northern and southern hemispheres , 1997 .

[30]  Neil Brough,et al.  Airborne measurements of peroxy radicals using the PERCA technique. , 2003, Journal of environmental monitoring : JEM.

[31]  P. Monks,et al.  Fundamental ozone photochemistry in the remote marine boundary layer: the soapex experiment, measurement and theory , 1998 .

[32]  A. McDaniel,et al.  An improved chemical amplifier technique for peroxy radical measurements , 1993 .

[33]  C. Cantrell,et al.  Dual-inlet chemical amplifier for atmospheric peroxy radical measurements. , 1996, Analytical chemistry.