Atmospheric NO(2) determination by 442-nm laser induced fluorescence.
An atmospheric monitor with a detectability of 0.6 ppbv, utilizing a compact He-Cd laser at 442 nm for excitation of the NO(2) molecules is described. Photon-counting techniques were employed to detect the NO(2) fluorescence transmitted through a bandpass liquid solution filter that did not fluoresce upon absorption of scattered laser light. Operational characteristics of the instrument are described. Results obtained in ambient air monitoring are presented.