Nitrogen dioxide is determined in air in the presence of much higher concentrations of sulfur dioxide on an hourly basis by using an automatic 24-hour sampler. Air is aspirated through a fritted-glass bubbler containing 0.1 N alkali solution. The absorbed nitrogen dioxide is determined colorimetrically as the azo dye by using it to diazotize sulfanilamide in phosphoric acid and then coupling it with N-( 1 -naphthyl)-ethylenediamine dihydrochloride. Nitrogen dioxide in the order of parts per hundred million of air can be determined. The sulfur dioxide present is also absorbed, but when oxidized to sulfate with hydrogen peroxide, does not interfere with the reaction.

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room temperature, the black precipitate was isolated by filtration through a dry, weighed, medium porosity, sintered glass funnel; washed thoroughly with methanol, acetone, and chloroform; dried in a vacuum desiccator; and weighed.Tellurium Complexes. Addition of tellurium (recovered from analyses) to an excess of bromine in a mixture of pyridine and methanol afforded a red complex, mp 310 °C (dec.

Pollution emissions from three representative types of jet engines were determined. Pollutants measured included nitrogen oxides, aldehydes, carbon monoxide, hydrocarbons, and odors. A method is presented for determining the magnitude of pollution emissions due to commercial jet aircraft operation by using basic emission factors.

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