Main sources of emission of benzene and its alkylated derivatives to the atmospheric air, particularly the vehicular ones, are characterized in the paper. Growing use of fuels. especially unleaded gasoline, leads to emission of considerable amounts of these aromatic hydrocarbons. The paper presents and discusses results of determinations of the content of benzene and its alkylated derivatives in engine fuels. Also emission factors of these hydrocarbons from commonly used in Poland types of cars, both with spark- and self-ignition engines, are considered. Profiles of investigated hydrocarbons in fuels and exhaust gases were determined. Respectively compared profiles proved the motor vehicles responsible for main part of the benzene and its alkylatcd derivatives in air in the vicinity of communication arteries.

Results of testing air quality in the vicinity of Gliwice transport routes arc presented in the paper. Assessment of air contamination with nitrogen dioxide from motor transport, for typical conditions dominating in big cities of high transit movement without any ring roads was the studies objective. Presented results will be used in the future to determine the impact of opening the ring road on air quality in the city. In the studies, the passive method of sampling, with further application of spectrophotometric technique to determine nitrogen dioxide concentration, was used. Average annual nitrogen dioxide concentrations were based on average daily concentrations measured from July 2004 to June 2005 at 16 measuring points. As they meet conditions for random distribution of measuring days and cover the measuring time, they were treated as average concentrations of nitrogen dioxide in a calendar year and were compared with a permissible concentration to make an assessment of air quality..