PHENOLS AND NITROPHENOLS AS TROPOSPHERIC POLLUTANTS - EMISSIONS FROM AUTOMOBILE EXHAUSTS AND PHASE-TRANSFER IN THE ATMOSPHERE

Motor exhaust gas from an automobile motor, operated under stationary conditions with unleaded gasoline, was sampled with two different impi nger bath methods. The samples were analyzed by gas chromatography/mas s spectrometry (GC/MS) for phenol, cresols and nitrated phenols. Pheno l and cresols were measured in the range of 80 - 220 nmol/L of exhaust gas from a noncatalyst engine, and nitrated phenols were found in the range of 9 - 36 nmol/L. A large reduction of total phenols down to 7% and less was observed when the engine was operated with a regulated t hree-way catalytic converter. The result of this study shows that exha ust gas sampling of phenols with alkaline aqueous impinger solutions l eads to an underestimation of phenol emissions, since phenols are not stable under high-pH conditions. In order to better assess the environ mental fate of nitrated phenols, laboratory experiments were conducted to measure the Henry's law constants of a series of nitrated phenols. For that purpose an apparatus for dynamic determination of the Henry' s law constants was constructed and successfully used. Special emphasi s was put on temperature dependence of the Henry's law constants.