Intercomparison of measurements of sulfur dioxide in ambient air by carbonate-impregnated filters and Teco pulsed-fluorescence analyzers

• Published in: Journal of Geophysical Research, Washington, DC Washington, DC, 1997-07, Vol.102 (D13), p.16267-16272
• Main Authors: Ferek, Ronald J., Covert, Paul A., Luke, Winston
• Format: Article
• Language: English
• ISSN: 0148-0227; 2156-2202
• DOI: 10.1029/96JD03587

In two previous University of Washington field programs, airborne measurements of SO2 using carbonate‐impregnated filters and a Teco pulsed‐fluorescence analyzer showed excellent agreement over a range of ambient concentrations from 2 to 127 ppbv. As part of the Gas‐Phase Sulfur Intercomparison Experiment (GASIE), ambient air, diluted fivefold to tenfold with zero air, was sampled in the concentration range of 0.02 to 4 ppbv. With the bulk of the measurements in the range of 40 to 230 parts per trillion by volume (pptv), agreement between the two techniques was again very good (regression equation: Teco =1.07(filter)+4.5 pptv, r=0.93). Using careful precleaning, impregnation, storage, and handling techniques for the filter substrates, at sub‐100 pptv concentrations, the filter method is capable of an accuracy of better than ±10% with a ±7 pptv uncertainty (due to blank variability) for 6 m3 samples. In addition, the Teco model 43S is capable of rather precise measurements of sub‐100 pptv concentrations (approximately ±16 pptv) provided a suitable averaging time is employed (at least 10 min).