Most poisonous gases can react with properly selected reagents to form colorful compounds. The change in color can be used for qualitative and quantitative determination of the poisonous gas in air if the optical density of the colored compound is measured. | in the proposed work, a solid wafer will be impregnated with I compounds that change their color from colorless to red when they react with NOX. A photocell which is sensitive to the intensity of the reflected light is currently used in our lab to determine the change in color and thus to quantify the concentration of the poisonous gas and the total exposure of the wafer to the gas. In Phase I, several wafers for detecting NOX will be tested, their performance curves for different NOX concentrations will be determined and an "optimal" wafer will be identified. In Phase II the presently used electronics will be miniaturized and a compact personal equipment will be built.
