The Metropolitan Region of Rio de Janeiro has approximately 16% of its territory as protected areas, mainly
forest formations of the Atlantic Forest (secondary and primary). This constitutes a significant green belt for
the city with a relevant role in the maintenance of biodiversity, water supplies, air quality and temperature
regulation. In this project, volatile organic compounds were determined in the Tijuca Forest (National Park)
and Pedra Branca, Chacrinha and Grajau State Parks to assess the impact of the urban emissions in the
forest. Air samples were collected using electropolished stainless steel canisters (Silonite®) and analyzed
using thermal desorption heart-cutting multidimensional gas chromatography (MDGC). The analytical
system consisted on an Agilent 7890A CG with a capillary flow technology (CFT) Deans Switch, two
chromatographic columns (a DB-624 and a PoraPLOT Q HT) and two detectors (a mass spectrometer and
a flame ionization detector) without cryogenic.
Concentrations of isoprene, the main biogenic compound, were in the interval 0,23 to 3,99 µg m-3
. Other
compounds, probably of anthropogenic origin were (concentrations in µg m-3
): propane (1,42-7,01), nbutane (2,76-7,93), ethane (1,02-5,95), isopentane (1,06-5,09), n-pentane (0,83-4,18), isobutane (1,31-
3,63), propene (<QL-0,47), ethene (<QL-0,71), benzene (0,29-0,55) and toluene (0,36-3.02).
Concentrations of anthropogenic compounds were lower in Tijuca and Pedra Branca forest, showing the
role of dense vegetation in pollution mitigation. Levels in Grajau and Chacrinha parks were lower than
concentrations currently determined in the urbanized area. These urban parks increase the connectivity
between the different elements of the biodiversity and have an important role in the improvement of
environmental quality. Rio de Janeiro depends on the Atlantic Forest but, also, the future of the Atlantic
Forest will be defined by the way in which the city protects the natural areas.