A Low-Cost System for Measuring ppb-Level NO₂

Abstract

SUMMARYA low-cost system to measure low-level nitrogen dioxide (NO 2 ) in an atmosphere was developed. Its major component included a sensor comprising filter paper treated with 3,3'-dimethylbenzidine (o-tolidine), a compound that reacts with NO 2 to generate color proportional to the NO 2 contacted. In addition to the system development, its utility was optimized and the characteristics of the sensor were defined. Originally developed to determine the NO 2 levels during direct-fired tobacco curing, the system may be used to determine the NO 2 levels in other situations. [Beitr. Tabakforsch. Int. 21 (2005)