Total OH reactivity in ambient air measured in the Pearl-River Delta in China 2006

We have developed a new instrument for the measurement of the total atmospheric OH reactivity, which is defined as the pseudo-first order loss-rate coefficient of OH, resulting from the reactions of OH with atmospheric trace gases like VOCs, CO, NOx etc. The instrument is capable of measuring the lifetime of OH (i.e., the reciprocal OH reactivity) in ambient air, by using a pulsed UV-pump laser-induced fluorescence (LIF) probe technique. The measurement range covers reactivities between 1 s−1 to about 150 s−1, corresponding to conditions from very clean to very polluted environments, with a time resolution of 1-3 min.