THE MEAASUREMENT OF AMBIENT $NO_{2}$ BY CAVITY RING-DOWN SPECTROSCOPY

Author Institution: Department of Chemistry and Air Pollution Research Center, University of California; Department of Chemistry, Calvin CollegeNitrogen dioxide $(NO_{2})$ is a principle component of photochemical smog that is present in polluted atmospheres at the parts per billion (ppb) level. In this work, cavity ring-down spectroscopy (CRDS) is utilized for the detection of ambient $NO_{2}$. Sub ppb limit of detection is routinely achieved. Experimental approaches to remove the particulates and to improve the detection limit and accuracy are investigated. Ambient measurements of $NO_{2}$ by CRDS are evaluated, and are compared side by side with the $NO_{2}$ measurements by chemiluminescence analysis