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INTERCOMPARISON OF OPTICAL REMOTE SENSING SYSTEMS FOR ROADSIDE MEASUREMENTS
Citation:
Ripberger*, C. T., J W. Jones*, AND M. O. Rodgers. INTERCOMPARISON OF OPTICAL REMOTE SENSING SYSTEMS FOR ROADSIDE MEASUREMENTS. Presented at 8th CRC On-Road Vehicle Emissions Workshop, San Diego, CA, 4/20-22/98.
Description:
The presentation describes results of an intercomparison of three optical remote sensing systems for measurements of nitric oxide emitted from passenger cars and light-duty trucks. The intercomparison included a standards comparison to establish comparability of standards, followed by a determination of a series of unknown mixtures in a dilution tube. The systems were also used to repetitively measure a group of vehicles of various sizes and emissions on a test track to evaluate the convergence of the nitric oxide measurement to the mean emissions of the vehicles as determined by postmeasurement Federal Test Procedure test cycles on the vehicles. The instruments were also used to measure a series of in-use vehicles at a nearby measurement site with comparisons made of the results reported by each instrument on the same vehicle. Results from the intercomparison indicated general agreement between the instruments, although some systematic biases were identified. Post-intercomparison tests of one of the instruments resulted in a modified instrument calibration that significantly improved overall system performance. Results from carbon monoxide and hydrocarbon intercomparison tests are also discussed.