A diffusion denuder for ambient nitrogen dioxide, based on quantitative collection on an alkaline active carbon surface, has been developed. Nitrogen dioxide yields nitrite anion which is extracted after sampling with water and analyzed by ion chromatography. It was found that the use of an alkali makes negligible the reduction of NO2 to NO, which occurs in working conditions on a simple surface of active carbon. Laboratory and field tests concerning sorption efficiency, capacity and effect of humidity have been carried out. The pre-exponential and esponent for the first term of the Gormley equation applied to annular geometry, were estimated. The detection limit for 24 h sampling is better than 0.05 ppb. Nitrogen oxide, ozone and PAN do not interfere in the determination. The method has been compared, during the field campaign 'Milano 93', with the corresponding integrated response of a chemiluminescence analyzer and with a DOAS system. The results obtained are reported and discussed.
Measurement of nitrogen dioxide in ambient atmosphere by carbon coated annular diffusion denuders / F., De Santis; DI FILIPPO, Patrizia; Allegrini, Ivo. - STAMPA. - 2:(1994), pp. 425-432. (Intervento presentato al convegno Proceedings of the 2nd International Conference on Air Pollution. Part 2 (of 2) tenutosi a Barcelona, Spain nel 27 September 1994 through 29 September 1994).
Measurement of nitrogen dioxide in ambient atmosphere by carbon coated annular diffusion denuders
DI FILIPPO, PATRIZIA;ALLEGRINI, IVO
1994
Abstract
A diffusion denuder for ambient nitrogen dioxide, based on quantitative collection on an alkaline active carbon surface, has been developed. Nitrogen dioxide yields nitrite anion which is extracted after sampling with water and analyzed by ion chromatography. It was found that the use of an alkali makes negligible the reduction of NO2 to NO, which occurs in working conditions on a simple surface of active carbon. Laboratory and field tests concerning sorption efficiency, capacity and effect of humidity have been carried out. The pre-exponential and esponent for the first term of the Gormley equation applied to annular geometry, were estimated. The detection limit for 24 h sampling is better than 0.05 ppb. Nitrogen oxide, ozone and PAN do not interfere in the determination. The method has been compared, during the field campaign 'Milano 93', with the corresponding integrated response of a chemiluminescence analyzer and with a DOAS system. The results obtained are reported and discussed.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
