Precursor Gas Monitoring NO y Monitoring Training Overview. Kevin A Cavender EPA-Office of Air Quality, Planning and Standards. Outline. Methodology Interferences and operational issues Commercially available NOy Monitors Calibration Current work in progress Summary. Methodology.
NOy Monitoring Training Overview
What is NOy?
NOy consists of the sum of all reactive nitrogen oxides. including NO, and NO2, and other nitrogen oxides referred to as NOz.
NO + NO2 + NOz = NOy
The major components of NOz include nitrous acids [nitric acid (HNO3), and nitrous acid (HONO)], organic nitrates [peroxyl acetyl nitrate (PAN), methyl peroxyl acetyl nitrate (MPAN), and peroxyl propionyl nitrate, (PPN)], and particulate nitrates.
NO is measured based on its chemiluminescent reaction with O3
NO + 03 -> NO2 + hv
The amount of light generated is linearly proportional to the concentration of NO.
NOy is measured by first passing the sample through a converter that converts NO2 and NOz species to NO and then measuring for NO as above.
Diagram of a High Sensitivity NOy instrument
Remote Converter on 10 meter tower
TAPI 200EU/501 NOy TEI 42CY