| Sumario: |
A great interest has arisen in establishing the impact of organic compounds on human health and air quality, especially those compounds emitted by automotive traffic. Knowledge of urban air pollutant concentrations is essential for the determination of exposure levels. With this information public health problems can be avoided and emissions sources can be identified. MTBE is one of such compound because of its effects both to the environment and to humans. In Costa Rica, as in many other parts of the world, MTBE has been added to gasoline up to 10% v/v. This study investigates ambient air concentration of MTBE in San Jose, Costa Rica. Samples were collected during October-December 2005 using Carbotrap® cartridges and analyzed by thermal desorption combined with capillary gas chromatography. MTBE levels ranged from < 0.1 to 7.0 ppbv, with the highest concentrations observed in the wet season's months (May to November). The highways and industrial areas were identified as MTBE's point sources, both related with vehicle emissions. High levels of MTBE were also found in the vicinity of a gas station. These values represent the first measurements made in a Central American location, but are similar to those reported in other urban areas. The MTBE ambient air levels in San Jose, Costa Rica were not known until this study in 2005.
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