MEASUREMENT TECHNIQUE FOR INORGANIC CHLORINE GASES IN THE MARINE BOUNDARY-LAYER

A technique was developed to measure inorganic Cl gases in the marine boundary layer. The inlet inertially removed coarse aerosol (>1-mum diameter), and an in-line filter removed fine aerosol. A trace gas concentrator positioned downstream incorporated an acidic mist chamber which sampled HCI* (including HCl, NOCl, ClNO2, and ClNO3), followed by an alkaline mist chamber which sampled Cl2* (including Cl2 and a portion of HOCl). Mist solutions were analyzed by ion chromatography. Estimated detection limits for HCl* and Cl2* were 39 and 13 pptv, respectively. Standard additions of calibration gases from permeation sources to ambient air were recovered quantitatively within source uncertainties. The sampler appears to discriminate against organic Cl gases. HCl* in coastal air near Miami varied from <39 to 268 pptv with lower mixing ratios at night. Ambient Cl2* Varied from <13 to 127 pptv with highest mixing ratios before dawn.