کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
4439988 | 1311041 | 2011 | 8 صفحه PDF | دانلود رایگان |
![عکس صفحه اول مقاله: Evaluation of ambient SO2 measurement methods at roadside sites Evaluation of ambient SO2 measurement methods at roadside sites](/preview/png/4439988.png)
Accurate measurements of SO2 at low ambient concentrations are needed in order to investigate the role of SO2 in particle nucleation events and the long-term impact of reductions in sulfur emissions in recent decades. In this study, artifacts in SO2 concentration measurements were investigated using two identical ion chromatography-based instruments (the Gas Particle Ion Chromatograph, GP-IC, Dionex Corporation) and two identical UV fluorescence-based SO2 analyzers (the TECO 43CTL, an industry standard). The SO2 concentration values measured with the GP-IC at roadside sites were compared with simultaneous side-by-side measurements made with the fluorescence analyzers. The SO2 concentration measured with the GP-IC had an ∼30% negative calibration artifact. When the GP-ICs were calibrated using an improved procedure developed in the course of this study, only a ±5% difference from the TECO analyzers remained, except under high NO concentration conditions. The fluorescence analyzers exhibited a positive artifact under elevated NO concentration conditions. Sulfur oxidation ratios were calculated based on the GP-IC-measured SO2 and SO42- concentrations and used to help identify potential emission sources. The SO2 concentrations measured with the GP-IC were also compared to data obtained from a National Air Pollution Surveillance (NAPS) speciation sampler equipped with a Na2CO3-coated denuder. Good correlation between SO2 data from the two methods was seen during five months of measurement, but the GP-IC SO2 data were ∼30% lower than the NAPS data. Deposition of SO2 within an urban street canyon is discussed as a possible explanation for this difference.
► The SO2 concentration measured with the GP-IC had a ∼30% negative calibration artifact.
► The GP-ICs were calibrated using an improved procedure developed in the course of this study.
► Only a ±5% difference from TECO analyzers remained, except under high NO concentration conditions.
► Sulfur oxidation ratios were calculated and used to help identify potential emission sources.
Journal: Atmospheric Environment - Volume 45, Issue 16, May 2011, Pages 2781–2788