A Small High-Sensitivity, Medium-Response Ozone Detector Suitable for Measurements from Light Aircraft

Abstract

An instrument for tropospheric O3 measurements based on the chemiluminescent reaction between nitric oxide and ozone is described. It was designed as part of a larger instrument package for simultaneous measurements of NO, NO2, NOy and O3 using smaller aircraft. The sensitivity of the O3 instrument is 2000 counts per second per ppbv O3, giving very high signal-to-noise ratios and a detection limit well below 0.1 ppbv. The instrument has been used in several research programs using the NCAR Sabreliner jet aircraft, and some results from these flights are presented. As configured for these flights, the instrument is operated with a 2-s integration time. However, suitable and readily made changes in operating conditions should allow sufficiently fast response for eddy correlation flux measurements from an aircraft or in ground-based programs.