First measurements of methyl tert-butyl ether (MTBE) in the ambient air in San Jose, Costa Rica

Abstract

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 OctoberDecember 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.

Analysis of Benzene Exposure Levels on Commuters Traveling within the Metropolitan Area of Costa Rica

“…The available information indicates that commuting can cause elevated personal exposure to toxic VOCs, including compounds known as carcinogenic such as benzene, which is closely linked to the induction of leukemia [8] [9]. In contrast to the number of studies carried out in developed countries and highly populated cities, such investigations are scarce in Latin-American countries [10], where similar to other regions, the rapid development and rapid urbanization have increased the traffic-related air pollution, which turns into an urgent need to gather information for future transport and urban healthcare planning [4] [5] [8].…”

“…Traditionally, the analysis of VOCs includes the use of solid adsorbents to concentrate the VOCs, followed by analyte transfer through either thermal desorption or solvent extraction into a gas chromatography system [1] [10]. Solid-phase microextraction (SPME) techniques have proven to be very useful tools in the analysis of wide VOCs in the air.…”

Relative Humidity Changes the Role of SO2 in Biogenic Secondary Organic Aerosol Formation

“…Its concentration in some forest regions could be higher than those of β-pinene and limonene that have been commonly studied. 26,27 Aerosol generation and growth from γ-terpinene (102 ppb) ozonolysis were first studied in a 1. and humid (RH = 45%) with high SO 2 (107 ppb, Table S1 in the Supporting Information, SI). The time evolution profiles of aerosol mass concentration in these experiments are shown in Figure 1a.…”