Assessment of the BTEX concentrations and reactivity in a confined parking area in Rio de Janeiro, Brazil

- BTEX concentrations are reported at a confined parking area in Rio de Janeiro.
- Vehicle exhaust and evaporative emissions are considered as the source of BTEX.
- Distinct evaporation profiles and reactivity explain the observed rank and ratios.
- Possibility of ozone formation is evaluated on the basis of the MIR scale.

In this work, the contribution of evaporative emissions from light passenger vehicles to the degradation of the air quality was investigated on the basis of the indoor quantification of the monoaromatic volatile compounds Benzene, Toluene, Ethylbenzene and Xylenes (BTEX), specifically, a confined shopping mall parking area in the northern zone of Rio de Janeiro, a site that represents the reality of the vehicular fleet of the Metropolitan Region of Rio de Janeiro. In order to evaluate the concentration of the BTEX compounds, samples were collected, by an active sampling system using charcoal cartridge as adsorbent. The samples were extracted with organic solvent and subsequently analyzed by gas chromatography-mass spectrometry (GCMS). The average results were 54.14 μg m−3 (benzene), 209.24 μg m−3 (toluene), 45.87 μg m−3 (ethylbenzene) and 118.93 μg m−3 (xylenes). These results are compared with results from the literature of vehicular emissions in confined spaces such as garages and tunnels. Possible correlations with emissions from moving vehicles, obtained from previous studies in a tunnel of large circulation and emissions obtained in other underground parkings, are also investigated. The results suggest different emission sources.

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