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RECOMMENDED METHODS FOR AMBIENT AIR MONITORING OF NO, NO2, NOY, AND INDIVIDUAL NOZ SPECIES
Citation:
Arnold, J. R., R. C. Cohen, R L. Dennis, K. G. Kronmiller, D J. Luecken, W A. McClenny, AND J. Stutz. RECOMMENDED METHODS FOR AMBIENT AIR MONITORING OF NO, NO2, NOY, AND INDIVIDUAL NOZ SPECIES. U.S. Environmental Protection Agency, Washington, DC, EPA/600/R-01/005 (NTIS PB2001-104379), 2001.
Impact/Purpose:
The main objective of this task is to provide the Agency with instrumentation to support its monitoring activities with respect to establishing the ambient air concentrations of ozone and ozone precursors such as nitrogen oxides and volatile organic compounds.
Description:
The most appropriate monitoring methods for reactive nitrogen oxides are identified subject to the requirements for diagnostic testing of air quality simulation models. Measurements must be made over 1 h or less and with an uncertainty of - 20% (10% for NO2) over a typical ambient concentration range extending from a lower limit of 1 ppbv. NO, NO2, HN03, PAN, and other reactive nitrogen oxides that exist at the 1-ppbv level and above, along with the compound sets designated as NOy (all reactive nitrogen oxide compounds), NOx (NO + NO2), and their difference, NOz, are included in this measurement requirement. New and/or improved measurement techniques for NO2 monitoring, including laser-induced fluorescence, photolytic conversion/NO, 03, chemiluminescence, differential optical absorption spectroscopy, and NO2/luminol chemiluminescence, are examined with reference to literature citations and to field monitoring as part of the 1999 Southern Oxidants Study (SOS) summer field study in Nashville, TN. Existing approaches to monitoring the other most prevalent reactive oxides of nitrogen are reviewed. At the lower end of the ambient monitoring range, research-grade instruments are often needed and operator skill, experience, and close attention are critical to proper instrument operation, calibration, and maintenance. If the most appropriate methods are used and other species and atmospheric parameters relevant to ozone production and accumulation are also accurately measured, air quality simulation models can be diagnostically tested and the basis for regulatory decisions such as the NOx State Implementation Plan (SIP) Call can be evaluated.
The U.S. Environmental Protection Agency through its Office of Research and Development assembled the information in this report with input from a number of prominent scientists and funded a research effort to provide field data for this report under Contract 68-D5-0049 to ManTech Environmental Technology, Inc. The report has been subjected to the Agency's peer and administrative review and has been approved for publication as an EPA document. Mention of trade names or commercial products does not constitute endorsement or recommendation for use