Atmospheric Chemistry and Physics Discussions www.atmos-chem-phys-discuss.net 1680-7367 1680-7375 4 1 2004 10.5194/acpd-4-343-2004 http://www.atmos-chem-phys-discuss.net/4/343/2004/ http://www.atmos-chem-phys-discuss.net/4/343/2004/acpd-4-343-2004.html http://www.atmos-chem-phys-discuss.net/4/343/2004/acpd-4-343-2004.pdf 343 363 2004-01-19 Measuring atmospheric naphthalene with laser-induced fluorescence M. Martinez H. Harder X. Ren R. L. Lesher W. H. Brune Department of Meteorology, Pennsylvania State University, University Park, Pennsylvania, USA now at: Max-Planck-Institut für Chemie, Mainz, Germany A new method for measuring gas-phase naphthalene in the atmosphere is based on laser-induced fluorescence at low pressure. The fluorescence spectrum of naphthalene near 308 nm was identified. Naphthalene fluorescence quenching by N₂, O₂ and H₂O was investigated in the laboratory. No significant quenching was found for H₂O with mixing ratio up to 2.5%. The quenching rate of naphthalene fluorescence is (1.98±0.18)×10^−11 cm³ molecule^−1 s^−1 for N₂, and (2.48±0.08)×10^−10 cm³ molecule^−1 s^−1 for O₂ at 297 K. Instrument calibrations were performed with a range of naphthalene mixing ratios between 5 and 80 parts per billion by volume (ppbv, 10^−9. In the current instrument configuration, the detection limit is estimated to be about 20 parts per trillion by volume (pptv, 10^−12) with 2σ confidence and a 1-min integration time. Measurement of atmospheric naphthalene in three cities, Nashville, TN, Houston, TX, and New York City, NY, are presented. Good correlation between naphthalene and major anthropogenic pollutants is found.