title: Direct measurement system of nitrogen dioxide in the atmosphere using a blue light-emitting diode induced fluorescence technique.
abstract: An instrument for measuring atmospheric nitrogen dioxide has been developed by a light-emitting diode induced fluorescence (LED-IF) technique. Air was introduced into a fluorescence detection cell. A pulsed blue light LED with a peak wavelength of 430 nm was irradiated to excite NO2 molecules in this cell. Fluorescence emitted from excited NO2 molecules was detected by a dynode-gated photomultiplier tube. The current detection limit of the LED-IF instrument was estimated to be 7.0 and 0.91 ppbv (parts per billion by volume) at 1-min and 1-h integration times, respectively, with a signal to noise ratio of 2. This result indicates that this LED-IF instrument can measure sufficiently precise 1-h values of NO2 concentrations in the urban atmosphere. An NO2 test observation and an intercomparison of the LED-IF instrument with an NO2 measurement system based on a photolytic converter/NO-O3 chemiluminescence method were performed in the urban atmosphere. Concentration differences between the two methods were within ±25% for about 90% of the data. It has been demonstrated by these observations that NO2 concentrations can be observed in the urban areas using the LED-IF instrument.
authors.affiliation: Graduate School of Engineering, Osaka Prefecture University, 1-1 Gakuen-cho, Naka-ku, Sakai, Osaka 599-8531, Japan.
authors.forename: Yasuhiro
authors.initials: Y
authors.lastname: Sadanaga
authors.affiliation: Graduate School of Engineering, Osaka Prefecture University, 1-1 Gakuen-cho, Naka-ku, Sakai, Osaka 599-8531, Japan.
authors.forename: Kazunari
authors.initials: K
authors.lastname: Suzuki
authors.affiliation: Graduate School of Engineering, Osaka Prefecture University, 1-1 Gakuen-cho, Naka-ku, Sakai, Osaka 599-8531, Japan.
authors.forename: Takatoshi
authors.initials: T
authors.lastname: Yoshimoto
authors.affiliation: Graduate School of Engineering, Osaka Prefecture University, 1-1 Gakuen-cho, Naka-ku, Sakai, Osaka 599-8531, Japan.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Bandow