Open AccessMeasurement technique for the determination of photolyzable chlorine and bromine in the atmosphere
Author(s) -
Impey G. A.,
Shepson P. B.,
Hastie D. R.,
Barrie L. A.
Publication year - 1997
Publication title -
journal of geophysical research: atmospheres
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.67
H-Index - 298
eISSN - 2156-2202
pISSN - 0148-0227
DOI - 10.1029/97jd00850
Subject(s) - bromine , halogen , chlorine , chemistry , propene , atmosphere (unit) , gas chromatography , halide , irradiation , photochemistry , alkyl , inorganic chemistry , catalysis , organic chemistry , chromatography , meteorology , physics , nuclear physics
A technique has been developed to enable measurement of photolyzable chlorine and bromine at trace levels in the troposphere. In this method, ambient air is drawn through a cylindrical flow cell, which is irradiated with a Xe arc lamp. In the reaction vessel of the photoactive halogen detector (PHD), photolytically active molecules Cl p (including Cl 2 , HOCl, ClNO, ClNO 2 , and ClONO 2 ) and Br p (including Br 2 , HOBr, BrNO, BrNO 2 , and BrONO 2 ) are photolyzed, and the halogen atoms produced react with propene to form stable halogenated products. These products are then sampled and subsequently separated and detected by gas chromatography. The system is calibrated using low concentration mixtures of Cl 2 and Br 2 in air from commercially available permeation sources. We obtained detection limits of 4 pptv and 9 pptv as Br 2 and Cl 2 , respectively, for 36 L samples.