You are here:
EVALUATION OF TWO APPROACHES FOR IMPROVED NITROGEN OXIDES MONITORING IN URBAN ATMOSPHERES
Citation:
Spicer, C., T. Kelley, AND G. Ward. EVALUATION OF TWO APPROACHES FOR IMPROVED NITROGEN OXIDES MONITORING IN URBAN ATMOSPHERES. U.S. Environmental Protection Agency, Washington, D.C., EPA/600/R-95/031.
Description:
Currently, instrumentation used to monitor nitrogen oxides in urban monitoring networks measure NO and "NOx", where NOx includes NO and NO2. hese NO2 measurements are subject to a positive bias from other oxidized nitrogen species (NOy) and it is believed that NOy measurements are useful in many ways including photochemical grid model diagnostics and emissions inventory verification. his report describes an evaluation of two approaches to monitor both NOx and NOy. ystem A makes use of two chemiluminescence instruments to monitor NO, NOy and NO2. ne of the instruments detects NO by its chemiluminescent reaction with O3, while the other detects NO2 by its chemiluminescent reaction with luminol. eated molybdenum catalytic converter is used to reduce NOy constituents to NO for detection. ystem B utilizes the luminol chemiluminescence reaction to detect NO2 and employs multiple catalysts to obtain measurements of NOx and NOy. itric oxide is determined as the difference between NOx and NO2. hese two approaches are evaluated in terms of linearity, converter efficiency, interferences and detection limits.