The Role of Oxides of Nitrogen
The oxides of nitrogen play an important role in atmospheric chemistry. In the troposphere, nitric oxide (NO) and nitrogen dioxide (NO₂) first function as catalysts in photochemical reaction cycles, that either produce or destroy ozone (O₃), second, they are precursors of nitric acid (HNO₃), which is an important constituent of acid precipitation. Compounds such as peroxyacetyl nitrate (PAN) are an important source of NO_X (NO + NO₂) in areas far off from anthropogenic sources. In the lower stratosphere, NO_Y and ClONO₂ are the principal reactive nitrogen species involved in ozone depletion. Accurate measurement techniques for the above mentioned compounds are important to be able to understand their chemistry and verify model calculations.

The Measurement Technique
The CON 765 utilizes the reduction of the higher oxides of NO in reaction with CO on a metal catalyst NO_Y + CO > NO + CO₂ + X and the subsequent detection of NO by a ECO PHYSICS chemiluminescence NO analyzer.

Continuous Monitoring
The CON 765 NO_Y gold converter enables the continuous and automatic monitoring of nitrogen oxides at remote clean air areas. Many features have been integrated to assure robust, accurate and safe operation. The conversion efficiency exceeds 90% and is linear over the complete range. The presence of water vapor in the sample reduces the interference of NH3 and HCN to a negligible level.

The Ideal Combination
The CON 765 is designed to be operated together with an ECO PHYSICS NO analyzer. The CON 765 is in use at several remote research and monitoring locations in Europe.

What is NO_Y?:

NOY = NOz + NOx
NOx = NO + NO₂
NOZ = HNO₃ + HONO + ₂N₂O₅ + HO₂NO₂ + PAN + NO₃ + Organic Nitrates – but not NH₃