IMPACTOS DOS BTEX EM ??REAS URBANAS DA CIDADE DO RIO DE JANEIRO

摘要

Most volatile organic compounds (VOC) have adverse effects on human health and the environment and react individually with different velocities and mechanisms to form ozone. The present work determined the concentration of 55 samples of benzene, toluene, ethylbenzene and xylenes (BTEX), an important subgroup of VOC, by active sampling with active carbon cartridge in the areas of Barra da Tijuca, Deodoro and Maracana between the months of December 2014 to September 2015. The samples were extracted with dichloromethane and analyzed by gas chromatography coupled to mass spectrometry (GC-MS). The percentage distribution of BTEX showed toluene as the most abundant compound in the three sites, with 54, 3% in Barra da Tijuca, 57, 4% in Deodoro and 38, 1% in the Maracana area of the total BTEX. The mean benzene/toluene (B/T) ratios were 0.12 (Maracana), 0.37 (Barra da Tijuca) and 0.23 (Deodoro), confirming the emission source as predominantly vehicular. Using reactivity scales, toluene was the compound that most contributed to the formation of ozone and benzene was less reactive than the others. The carcinogenic risk was considered indifferent in all sites.