Eduardo Behrentz

Characterization and source identification of VOC species in Bogotá, Colombia

In this article, volatile organic compounds (VOC) were characterized in ambient air at three different monitoring sites within the urban perimeter of Bogota, Colombia. On-line VOC measurements were conducted using a Synstech Spectras portable gas chromatograph with a temporal resolution of 30 min. Average VOC concentrations were higher at two of the sampling sites, which are characterized by intensive industrial and commercial activities, and high vehicular activity. Analyses of the diurnal behavior of total VOC showed that concentrations tend to be higher in the morning (at around 8:00 LT) and during the evening (around 22:00 LT). Such trends suggest the influence of road traffic activity in the surroundings of the measuring sites on VOC levels. According to our results, alkanes are the most abundant hydrocarbons in the ambient air in Bogota (about 80% of the total VOC), while alkenes represent only 15% of the total VOC. We computed the ozone formation potential (OFP) using the maximum incremental reactivity (MIR) concept and evaluated the role of each VOC in the O 3 formation. These results show that ethene, propene, n-butane, i-pentane and isoprene are the species with the highest OFP (noting that high concentrations are not necessarily linked with elevated O 3 production). Finally, we used principal components analysis to identify the sources of different VOC. Our results showed that most of the compounds included in this study are emitted by road traffic. The receptor modeling also shows that the top-five compounds in terms of O 3 production come mainly from the exhaust of gasoline vehicles.

Indoor air pollution associated with the use of natural gas appliances in households in Bogota, Colombia: levels and determinants

Levels and determinants of indoor carbon monoxide (CO) pollution were characterised in a pilot sample of households in Bogota, Colombia, in which natural gas appliances (NGA) were frequently used. Real-time CO concentration measurements were conducted using Langan T15 electrochemical cells in kitchen and living rooms, at 73 homes. Results show that the use of NGA has a direct impact on indoor air quality with CO concentrations ranging between 5 and 150 parts-per-million. In 14 out of the 73 homes, CO concentrations were above the World Health Organization standards during at least 10% of the day. This is a matter of concern for local public health authority since the number of reported cases of CO involuntary intoxications in the city has significantly increased since 2008. Evidence presented hereby has important implications in regard to NGA installation standards and housing polices (especially in the case of low income dwelling). It urges to involve healthy-house concepts in building codes, to prevent inadequate indoor air quality and to improve people living conditions.