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EVALUATION AND USE OF STAND-ALONE COMMERCIAL PHOTOLYTIC CONVERTERS FOR NO2 TO NO CONVERSION
Citation:
Kronmiller, K. G. AND W A. McClenny. EVALUATION AND USE OF STAND-ALONE COMMERCIAL PHOTOLYTIC CONVERTERS FOR NO2 TO NO CONVERSION. Presented at Symposium on Air Quality Measurement Methods and Technology, Research Triangle Park, NC, April 20-22, 2004.
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:
Two types of stand-alone commercial photolytic converters of NO2 to NO are now available for use with NO, O3 chemiluminescence monitors for the measurement of NO2. Both units have been tested for interferences resulting from photolysis of HONO or from decomposition of PAN. One unit is based on the use of a broadband source and incorporates a source cooler. This unit has been used for two month-long field studies, one in May of 2002 and a second in October 2003. The results indicate that the converter is robust and reliable with conversion efficiencies of of 35 to 70% depending on the air flow rate through the converter. The second commercial unit is based on a LED array with output emission wavelength at 390 to 400 nm. This unit is being field tested for use as part of on-going tests. Based on results so far the prospect of using one of the stand-along converters with an external, heated metal converter and a chemiluminescence monitor to measure NO, NO2, and NOy seems reasonable.
Although this work was reviewed by EPA and approved for publication, it may not necessarily reflect official Agency policy.