Levels of Volatile Carbonyl Compounds in the Atlantic Rainforest, in the City of Rio de Janeiro

When Europeans arrived in America, the Brazilian Atlantic rainforest covered approximately 1,290,000km(2). Now, only 8% of the biome's original vegetation remains. One of the largest areas is Tijuca Forest National Park. In this work, the concentrations of 13 carbonyl compounds in an isolated area inside Tijuca Forest, in an urban park with primary and secondary vegetation (Gericino Natural Park) and in two typical urban areas (Tijuca District and the city of Nilopolis) were determined. The main compounds were formaldehyde and acetaldehyde. The formaldehyde mean concentrations were 0.98 +/- 1.00, 1.27 +/- 1.67, 3.09 +/- 1.60 and 2.33 +/- 2.17gm(-3) for Tijuca Forest, Gericino Natural Park, Tijuca District and the city of Nilopolis, respectively. The mean acetaldehyde concentrations were, for the same locations, 0.93 +/- 1.05, 2.94 +/- 2.54, 2.78 +/- 0.91 and 5.48 +/- 1.90gm(-3). The results indicate that the compounds measured within the forest are transported from the city and that the trees play an important role in removing air pollutants. In contrast, the Gericino protected area is heavily affected by urban emissions, and its capacity to dilute or absorb pollutants is low because of the sparse vegetation.