Impact of the Meteorology Conditions on the Particulate Matter Dispersion from an Industrial Complex into Urban and Suburban Areas

The aim of this work was to assess the influence of meteorological conditions on the dispersion of particulate matter from an industrial zone into urban and suburban areas. The particulate matter concentration was related to the most important meteorological variables such as wind direction, velocity and frequency. A coal-fired power plant was considered to be the main emission source with two stacks of 225 m height. A middle point between the two stacks was taken as the centre of two concentric circles with 6 and 20 km radius delimiting the sampling area. About 40 sampling collectors were placed within this area. Meteorological data was obtained from a portable meteorological station placed at approximately 1.7 km to SE from the stacks. Additional data was obtained from the electrical company that runs the coal power plant. These data covers the years from 2006 to the present. A detailed statistical analysis was performed to identify the most frequent meteorological conditions concerning mainly wind speed and direction. This analysis revealed that the most frequent wind blows from Northwest and North and the strongest winds blow from Northwest. Particulate matter deposition was obtained in two sampling campaigns carried out in summer and in spring. For the first campaign the monthly average flux deposition was 1.90 g/m2 and for the second campaign this value was 0.79 g/m2. Wind dispersion occurred predominantly from North to South, away from the nearest residential area, located at about 6 km to Northwest from the stacks. Nevertheless, the higher deposition fluxes occurred in the NW/N and NE/E quadrants. This study was conducted considering only the contribution of particulate matter from coal combustion, however, others sources may be present as well, such as road traffic. Additional chemical analyses and microanalysis are needed to identify the source linkage to flux deposition levels.

Cartografia de zonamento geotécnico em frentes de escavação de maciços rochosos heterogéneos (túnel do Marão): aplicação da classificação geomecânica GSI|2013

Este estudo pretende discutir a validade da aplicação da mais recente versão do “GSI – Geological Strength Index” (Hoek et al., 2013) em maciços rochosos heterogéneos por aplicação num projecto de obra subterrânea em execução. O estudo envolveu a caracterização geológicageotécnica nas duas frentes de escavação da frente “Poente” da empreitada de construção do Túnel do Marão (N de Portugal) tendo sido cartografados 305 metros no conjunto das duas frentes em 74 avanços consecutivos. Para esta caracterização foram coligidos e uniformizados dados geológicos, geotécnicos e geomecânicos relativos aos levantamentos realizados a cada avanço. A técnica da amostragem linear foi aplicada para a cartografia das descontinuidades que permitiu estabelecer o grau de compartimentação do maciço rochoso. Além disso, procedeu‐se a um tratamento estatístico das descontinuidades, bem como dos parâmetros geológico‐geotécnicos e geomecânicos associados. Os zonamentos geotécnicos e geomecânicos das secções em análise foram realizados sempre em estreita ligação com o conhecimento das características do maciço in situ. Procurou‐se estabelecer termos de comparação entre a versão do GSI|2013 e as versões anteriores (GSI|98, GSI|2001) por aplicação para os avanços cartografados. Pretende‐se que este trabalho contribua para um maior conhecimento da mais recente versão do “Geological Strength Index” (2013) para a sua aplicabilidade em projectos de geoengenharia.