Total OH loss rate measurement

A new instrument has been developed to measure the total decay rate of OH in ambient air. The instrument is based on the discharge flow technique in which OH generated within the instrument is reacted with ambient air pulled into the flow tube. The OH decay is monitored by laser-induced fluorescence. This total decay rate is compared to the sum of the individual decay rates of OH with each trace species measured in the air to test for missing OH reactants. OH decay rates measured in an urban environment in the summer of 1999 illustrates the promise of this technique.