We have reported the use of fast gas chromatography (GC) with luminol chemiluminescent detection for measurement of NO2 and the peroxyacyl nitrates (1), important gas-phase species in photochemical air pollution. Peroxyacetyl nitrate (PAN) is the primary peroxyacyl nitrate produced during the oxidation of hydrocarbons in the presence of NO and NO2. Simultaneous measurements of NO2 and PAN enable determination of the levels of the peroxyacetyl radical in the air, as PAN is in thermal equilibrium with the peroxyacetyl radical and NO2. Past measurements of PAN and NO2 with this method were made in Centerton, NJ; Deer Park, TX; and Phoenix, AZ. We redesigned our previous instrument to make it smaller and lighter for easy deployment on aircraft platforms and modified the software to allow real-time data integrations. In this work, we review the method and highlight the modifications made to the instrument, including a new cell design that enables easy monitoring of luminol detection with a Hamamatsu HC-135 photon counting system. Data taken on board the NOAA Twin Otter will be presented from the recent Bay Region Atmospheric Chemistry Experiment (BRACE) in Tampa, FL, in May 2002. NO2 concentrations measured by the fast GC luminol technique will be compared with simultaneous on-board measurements made by photolytic conversion to NO followed by ozone chemiluminescence.

1. J.S. Gaffney, R.M. Bornick, Y.-H. Chen, and N.A. Marley, "Capillary Gas Chromatographic Analysis of Nitrogen Dioxide and PANs with Luminol Chemiluminescent Detection." Atmospheric Environment, 32, 1145-1154 (1998).