Two versions of yhe Emission Inventory (EI) are generated for the city of Bogota, Colombia. In the first version (EI-1), CORINAIR traffic emission factors (EFs) are used. In the second (EI-2), bulk traffic EFs calculated for the city, using in situ measurements and inverse modelling techniques at street level, are used. EI-2 traffic emission are 5, 4 and 3 times bigger than the corresponding values in EI-1, for CO, PM10 and NMVOCs, respectively. The main goal of this study consists in evaluating the two versions of the EI when introduced into a mesoscale air quality model. The AOT (accumulated exposure over a threshold) index is calculated for comparison between observed and simulated concentrations of primary pollutants. Simulated concentrations using EI-2 are closer to the observed values. This comparison allows us to extract some conclusions of the methodology used to calculate the EFs. Local factors like the driving behavior, the altitude, vehicle technology and an aged fleet cannot be totally included and corrected in the standard methodologies, and seem to be more important than obtaning very detailed and precise information on the classification of the fleet or driving speeds. Under financially limited and fast changing situations, as in the case of many developing countries, a simple methodology to estimate bulk traffic EFs and to evaluate the EI, is of utmost importance. The use of combined techniques such as in situ measurements to estimate bulk traffic EFs, and further evaluations of the inventories with numerical models, proved to be a useful tool for this purpose
RESUMENEn este trabajo se caracterizan compuestos orgánicos volátiles (VOC, por sus siglas en inglés) en aire ambiente en tres sitios de monitoreo ubicados en el perímetro urbano de Bogotá, Colombia. Se realizaron mediciones en línea de VOC con una resolución temporal de 30 min utilizando un cromatógrafo portátil Synstech Spectras. Las concentraciones medias de VOC fueron más altas en los dos sitios de muestreo, que se distinguen por sus actividades industriales y comerciales, así como por contar con una alta actividad vehicular. Los análisis del comportamiento diurno de los VOC mostraron que las concentraciones tienden a ser mayores durante la mañana (alrededor de las 8:00 a.m.) y la noche (alrededor de las 10:00 p.m.). Estas tendencias sugieren la acuerdo con los resultados obtenidos, los alcanos son los hidrocarburos más abundantes en el aire ambiente de Bogotá (cerca de 80% del total de VOC), en tanto que los alquenos representan únicamente 15% del total de VOC. Se calculó el potencial de formación de ozono (OFP, por sus siglas en inglés) utilizando el concepto de máxima reactividad incremental (MIR, por sus siglas en inglés) y se evaluó el papel de cada VOC en la formación de O 3 . Estos resultados muestran que el eteno, el propeno, el n-butano, el i-pentano y el isopreno son las especies con mayor OFP (resultando que las altas concentraciones no necesariamente están asociadas a mayor potencial para la producción de O 3 ). Finalmente, se hizo un análisis de componentes principales para los cinco principales compuestos en términos de producción de O 3 proceden primordialmente de los tubos de escape de vehículos a gasolina. ABSTRACTIn this article, volatile organic compounds (VOC) were characterized in ambient air at three different monitoring sites within the urban perimeter of Bogotá, 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 Bogotá (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 ...
Colombia is the largest producer of palm oil in America. An estimate of the carbon footprint of a Colombian agro-industrial company during 2011 is presented in this paper. Only the operations conducted within the company's processing plant are considered. Greenhouse gas emissions are estimated by applying the methodology proposed by the Intergovernmental Panel on Climate Change (IPCC), which considers the physical chemical properties and emission factors for fuels and activities described by the Colombian Mining and Energy Planning Unit. The carbon footprint is found to be 115,352 t CO2 for the studied year. Of these emissions, 58% correspond to anaerobic open lagoons for water treatment, 41% to stationary combustion equipment, and only 1% to transportation vehicles and heavy machinery owned by the company. By identifying emission sources and estimating the carbon footprint, this company is now able to set objectives leading to a reduction in emissions and the implementation of strategies to minimize environmental effects caused by this process.Keywords: Palm Oil Extraction, Emission Factor, Greenhouse Gases, Carbon Footprint. ResumenColombia es el principal productor de aceite de palma en América. Este trabajo presenta la estimación de la Huella de Carbono de una empresa agroindustrial colombiana durante el año 2011, teniendo en cuentaaplica únicamente las operaciones realizadas por su planta de beneficio. Se estimó la emisión de los principales gases de efecto invernadero mediante la aplicación de la metodología propuesta por el IPCC, considerando las propiedades fisicoquímicas y los factores de emisión de los combustibles y actividades propuestos por entidades como la Unidad de Planeación Minero Energética. La huella de carbono generada para el año de estudio fue de 115.352 t CO2, el 58% corresponde a las lagunas anaerobias para el tratamiento de aguas, el 41% a los equipos de combustión fija y solo el 1% a los vehículos de transporte y maquinaria pesada de la empresa. Con la identificación de las fuentes de emisión y la estimación de la huella de carbono, esta empresa tiene la posibilidad de establecer metas efectivas de reducción de emisiones e implementar estrategias que disminuyan los impactos ambientales que genera su proceso. Palabras clave:
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