Development of an ambient pressure laser-induced fluorescence instrument for nitrogen dioxide

Abstract

Concerns about the health effects of nitrogen dioxide (NO2) and its role in forming deleterious atmospheric species have made it desirable to have low-cost, sensitive ambient measurements of NO2. We have developed a continuous-wave laser-diode laser-induced fluorescence (LIF) system for NO2 that operates at ambient pressure, thereby eliminating the need for an expensive pumping system. The current prototype system has achieved sensitivity several orders of magnitude beyond previous efforts at ambient pressure (limit of detection of 2 ppb, 60 s averaging time). Ambient measurements of NO2 were made in Portland, Oregon using both the standard NO2 chemiluminescence method and the LIF instrument and showed good agreement (r2 = 0.92).