title: Influence of photolysis on multispectral photoacoustic measurement of nitrogen dioxide concentration.
abstract: Multispectral photoacoustic instruments are commonly used to measure aerosol and nitrogen dioxide (NO2) light absorption coefficients to determine the radiation budget of the atmosphere. Here a new photoacoustic system is developed to explore the effect of photolysis on the measured signal in a multispectral photoacoustic spectrometer In this system, a 405-nm laser is used primarily as light source for photolysis. Additionally, a well-overlapped 532-nm laser, modulated at the resonant frequency of the photoacoustic instrument, is used to probe the NO2 concentration. As a result, the photolysis effect at 405 nm can be observed by the photoacoustic instrument through the 532-nm laser. This work determines an 11% reduction of the photoacoustic signal caused by the photolysis effect for typical conditions, which needs to be taken into account when calibrating multispectral photoacoustic spectrometers with NO2.
authors.affiliation: Desert Research Institute, Nevada System ofHigher Education, Reno, NV89512, USA. tgxfff@hotmail.com
authors.forename: Guoxun
authors.initials: G
authors.lastname: Tian
authors.forename: Hans
authors.initials: H
authors.lastname: Moosmüller
authors.forename: W Patrick
authors.initials: WP
authors.lastname: Arnott
mesh_terms: D009585:Nitrogen Dioxide / Q000032:analysis*; D061088:Photoacoustic Techniques / Q000295:instrumentation*; D010782:Photolysis
chemical_list: D009585:Nitrogen Dioxide