科研之友
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摘要
Attaining the National Ambient Air Quality Standard (NAAQS) for ozone (O(3)) could cost billions of dollars nationwide. Attainment of the NAAQS is judged on O(3) measurements made by the Federal Reference Method (FRM), ethylene chemiluminescence, or a Federal Equivalent Method (FEM), predominantly ultraviolet (UV) absorption. Starting in the 1980s, FRM monitors were replaced by FEMs so that today virtually all monitoring in the United States uses the UV methodology. This report summarizes a laboratory and collocated ambient air monitoring study of interferences in O(3) monitors. Potential interferences examined in the laboratory included water vapor, mercury, o-nitrophenol, naphthalene, p-tolualdehyde, and mixed reaction products from smog chamber simulations of urban atmospheric photochemistry. UV absorption O(3) monitors modified for humidity equilibration were also collocated with UV FEM O(3) monitors at six sites in Houston, TX, during the 2007 summer O(3) season. The results suggest that humidity and interfering species can positively bias (overestimate) O(3) measured by FEM monitors used to determine compliance with the O(3) standards. The results also suggest that humidity equilibration can mitigate this bias.
- 出版日期2010-11
