Showing papers by "Maria C.M. Alvim-Ferraz published in 2010"

Influence of traffic emissions on the carcinogenic polycyclic aromatic hydrocarbons in outdoor breathable particles.

Abstract: Because polycyclic aromatic hydrocarbons (PAHs) have been proven to be toxic, mutagenic, and/or carcinogenic, there is widespread interest in analyzing and evaluating exposure to PAHs in atmospheric environments influenced by different emission sources. Because traffic emissions are one of the biggest sources of fine particles, more information on carcinogenic PAHs associated with fine particles needs to be provided. Aiming to further understand the impact of traffic particulate matter (PM) on human health, this study evaluated the influence of traffic on PM10 (PM with aerodynamic diameter <10 µm) and PM2.5 (PM with aerodynamic diameter <2.5 µm), considering their concentrations and compositions in carcinogenic PAHs. Samples were collected at one site influenced by traffic emissions and at one reference site using low-volume samplers. Analysis of PAHs was performed by microwave-assisted extraction combined with liquid chromatography (MAE-LC); 17 PAHs, including 9 carcinogenic ones, were quantifie...

Biodiesel Production through Transesterification of Poultry Fat at 30 °C

Abstract: Biodiesel is an alternative fuel to fossil diesel whose major disadvantage is the dubious economical viability of the production process, due to the high raw material costs. In the work here reported, biodiesel was produced from poultry fat, a potentially good alternative raw material due to its low price and availability. The specific objectives of the work were (i) to study biodiesel production from poultry fat by homogeneous alkaline transesterification; (ii) to evaluate and improve the parameters affecting the reaction, namely, temperature, time, methanol to fat molar ratio, and concentration of the catalyst; and (iii) to evaluate the quality of the obtained biodiesel, according to the European biodiesel quality standard EN 14214. The product yield varied from 73 to 86 wt %. Regarding the product quality, independently of the reaction conditions used, density, acid value, flash point, copper corrosion, linolenic methyl ester content, and iodine number fulfilled EN 14214; however, viscosity and purity ...

Contribution of traffic and tobacco smoke in the distribution of polycyclic aromatic hydrocarbons on outdoor and indoor PM2.5

Abstract: Traffic emissions and tobacco smoke are considered two main sources of polycyclic aromatic hydrocarbons (PAHs) in indoor and outdoor air. In this study, the impact of these sources on the level of fine particulate matter (PM2.5) and on the distribution of 15 PAHs regarded as priority pollutants by the US-EPA on PM2.5 were evaluated and compared. Outdoor and indoor PM2.5 samples were collected during winter 2008 in Oporto city in Portugal, for sampling periods of 12 and 24 hours, respectively. The outdoor PM2.5 were sampled at one site directly influenced by traffic emissions and the indoor PM2.5 samples were collected at one home directly influenced by tobacco smoke and another one without smoke. A methodology based on microwave-assisted extraction and liquid chromatography with fluorescence detection was applied for the efficient PAHs determination in indoor and outdoor PM2.5. PAHs in indoor PM2.5 concentrations were significantly influenced by the presence of traffic and tobacco smoking emissions. The mean of ΣPAHs in the outdoor traffic PM2.5 was not significantly different from the value attained in the indoor without smoking site. The tobacco smoke increased significantly PAHs concentrations on average about 1000 times more, when compared with the outdoor profile samples suggesting that tobacco smoking may be the most important source of indoor PAHs pollution.

Estimation of pollutant partition in sandy soils with different water contents.

Abstract: The objectives of this work were: (1) to identify an isotherm model to relate the contaminant contents in the gas phase with those in the solid and non-aqueous liquid phases; (2) to develop a methodology for the estimation of the contaminant distribution in the different phases of the soil; and (3) to evaluate the influence of soil water content on the contaminant distribution in soil. For sandy soils with negligible contents of clay and natural organic matter, contaminated with benzene, toluene, ethylbenzene, xylene, trichloroethylene (TCE), and perchloroethylene (PCE), it was concluded that: (1) Freundlich’s model showed to be adequate to relate the contaminant contents in the gas phase with those in the solid and non-aqueous liquid phases; (2) the distribution of the contaminants in the different phases present in the soil could be estimated with differences lower than 10% for 83% of the cases; and (3) an increase of the soil water content led to a decrease of the amount of contaminant in the solid and non-aqueous liquid phases, increasing the amount in the other phases.

Influence of land-sea breezes on nocturnal ozone maxima observed in urban sites

Abstract: Sometimes nocturnal ozone maxima have been observed, contrasting with the nocturnal minimum values of typical daily profile. The influence of land-sea breeze on the nocturnal ozone maxima was analysed in two urban sites strongly influenced by traffic emissions. Results showed that the increase in nocturnal ozone concentration, as well as its maxima was caused by horizontal advection of ozone, associated with the development of land-sea breezes. This conclusion, obtained considering 18 months of two years, is in agreement with the only previous study that analysed the influence of land-sea breeze, but considering simply the four warmest months of one year.

Remediation of soils contaminated with trichloroethylene

Abstract: Soil contamination is a common problem in our society. Several activities introduce contaminants in soils affecting their quality and future utilization. In order to invert this situation and to avoid further spreading of the contaminant several remediation technologies could be used. For soils contaminated with trichloroethylene (TCE), Soil Vapor Extraction (SVE) can be an efficient remediation technology. It involves the application of vacuum to the soil matrix creating an airflow that conduce the volatized contaminant to extraction wells that lead them to the exterior of the soil where they are properly treated. This work presents the results obtained in the soil vapor experiments performed in a laboratory using soils with different water contents contaminated with TCE. These experiments aimed the study of the influence of soil water content and the airflow used in the remediation time and on the process efficiency. The results showed that in sandy soils contaminated with TCE: a) for similar levels of contamination, the increase of the soil water content from 0 to 4% created an increase of the concentration of TCE in the gas phase of the soil, in some cases by almost 50%; b) the influence of water content is not significant being overlapped by influence of the airflow rate; c) SVE performed with higher airflow rates had shorter remediation times (in some cases four times shorter) without any significant impact on the process efficiencies (fluctuations of 1 to 3%); and d) for the experimented soils, the utilization of higher airflow rates led to shorter and consequently cheaper remediation. Remediation of soils contaminated with trichloroethylene*