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STATUS OF SEMI-CONTINUOUS MONITORING INSTRUMENTATION FOR GAS AND WATER SOLUBLE PARTICLE COMPONENTS NEEDED FOR DIAGNOSTIC TESTING OF AMBIENT AIR QUALITY SIMULATION MODELS
Citation:
McClenny, W A., K. G. Kronmiller, K. D. Oliver, H. H. Jacumin Jr., AND E. H. Daughtrey Jr. STATUS OF SEMI-CONTINUOUS MONITORING INSTRUMENTATION FOR GAS AND WATER SOLUBLE PARTICLE COMPONENTS NEEDED FOR DIAGNOSTIC TESTING OF AMBIENT AIR QUALITY SIMULATION MODELS. U.S. Environmental Protection Agency, Washington, DC, EPA/600/R-02/072 (NTIS PB2004-100894), 2003.
Impact/Purpose:
1. Provide the Agency with semi-continuous and real-time instrumentation for its monitoring of ozone, ozone precursors, and reaction products of ozone formation.
2. Provide the Agency with semi-continuous and real-time instrumentation for its monitoring of water-soluble PM components and water-soluble atmospheric gases.
Description:
This status report documents the effort by the National Exposure Research Laboratory (NERL), Office of Research and Development (ORD) of the U.S. Environmental Protection Agency (U.S. EPA) to provide methods of measurement, including calibration procedures, that meet the requirements for diagnostic testing of models describing atmospheric photochemistry. These requirements include a measurement uncertainty of ± 0.2 ppbv (± 0.1 for NO2) at 1.0 ppbv (or equivalent for particles) for compounds mentioned here as specified by scientists in the AMD, NERL. New developments for monitors of NO2, HCHO, H2O2, HNO3, HONO, NH3, volatile organic compounds (VOCs) (including n-aldehydes), particulate nitrate, particulate sulfate, and particulate ammonium are discussed in the report. Descriptions of instrument design and principle of operation for NO2, HCHO, and water soluble gases and particulate matter are presented.
Since field comparisons among different methods are often the accepted approach for identifying monitoring problems and establishing consensus among scientists specializing in monitoring methods, recent activities have emphasized field studies. Results from the 2002 Tampa, FL Bay Regional Atmospheric Chemistry Experiment (BRACE), the 2001 Philadelphia, PA, Northeast Ozone Particle Study (NE-O3PS) study, and the 1999 Nashville, TN Southern Oxidants Study (SOS) are shown. Of particular note are the preliminary results of field monitoring of NO2 in the BRACE field study with systems using new commercial photolytic converters for NO2 to NO conversion followed by chemiluminescence detection. In the NE-O3PS field study comparisons of HNO3, HONO, SO2, and nitrate and sulfate in particulate matter between the Harvard School of Public Health (HSPH) EPA Denuder System (HEADS) (10-h average) and the average response from the Texas Tech University (TTU) semi-continuous system (15 min updates) provide an interesting (an so far unresolved) example of a multiplicative error in a field study database. Current plans call for a more definitive statistical comparison of methods using the existing field monitoring database in the NE-O3PS and BRACE studies and additional field comparisons of methods in the upcoming 2003 Seattle field study.
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-D-00-206 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 for use.