Lígia Torres Silva

Assessing the influence of urban geometry on noise propagation by using the sky view factor

The impact of traffic noise can be prevented by suitable planning measures. This study analyses the relationship between urban geometry and traffic noise, recognizing that the arrangement of buildings and streets greatly influences urban noise. The study was carried out in Braga, a medium-sized Portuguese city, by selecting locations with different urban geometries. At each site, the equivalent continuous sound level was measured. Furthermore, the urban geometry was evaluated by using the sky view factor, a parameter which shows the degree of sky obstructed by buildings. Results show an inverse proportionality between noise and the sky view factor. The highest noise levels were found in areas with a low sky view factor. The results also indicate that the sky view factor is a parameter which can potentially be used in research on urban noise.

Assessment of energy efficiency in street lighting design

Street lighting design aims to ensure adequate night visibility conditions for both vehicular and pedestrian traffic as well as to improve security conditions for persons, goods and property in the neighbourhood. In addition to this, and in order to meet concerns about environmental protection and sustainable development, the design of street lighting should take into account the optimization of its energy efficiency, as excessive energy usage is associated with an increase in polluting emissions, namely CO2. Considering that street lighting generally presents a significant consumption of electricity that is often possible to reduce, the use of good design practices which will maximize the efficiency of lighting equipments and accessories as well as minimize the upward light emissions and adjust the intensity of lighting according to outdoor needs is crucial. The main goal of this work is to present a new simple tool which can assess street lighting performance in the context of energy efficiency. Three indicators were developed: one to evaluate lighting performance and two others to evaluate energy performance. These indicators were quantified and combined according to weighting and aggregation procedures, resulting in a synthetic score for the street lighting design. The assessment tool was applied to a business park located in Viana do Castelo, in Portugal, and the results are discussed.

Evaluating conflict zones of air pollution in a mid-sized city

The urban argument currently assumes an extreme level of relevance for governments and the society in general, due to the exponential increase of people living in cities and the consequent associated degradation of quality of life. Growth is continuously applying pressures over resources, infrastructures and facilities, affecting negatively the standard of living in cities. In this context, evaluating and monitoring the urban environmental quality has become a main issue, particularly important when considered as a decision-support tool that contributes to more liveable and sustainable cities. Viana do Castelo is a mid-sized city located on the northwest seaside, which undertook the challenge of developing an environmental program leading to the integration in a Healthy Cities European Network. The identification of urban air quality levels and people exposure was considered a priority in this program. The scientific toolbox adopted to develop the studies includes air quality simulation models and a GIS platform. Based on traffic and site physical characteristics, air pollution maps were created and overlaid together with the land-use and population distribution layers. This combination was the basis for the identification of critical zones, both in terms of air quality levels and people exposure to this kind of pollution. Furthermore, the results were used to sort out mitigation measures and priorities, particularly important in a context of limited resources. This paper aims to present the approach, including the theoretical framework, and to discuss the results and their role within the city’s quality of life argument.

An urban environmental monitoring and information system

Evaluating, monitoring and informing about urban environmental quality has become a main issue, particularly important when considered as a decisionmaking tool that contributes to more habitable and sustainable cities. Following a tendency observed in other European cities, the city of Braga (Portugal) has decided to create an infrastructure for environmental data acquisition and a webbased platform as a public information system. Some of the innovations introduced in this new platform include the use of mobile instrumented units, the extensive use of simulation software to create long-term pollution (air and noise) maps, and the presentation of the information through a geographical interface developed over Google Maps technology. This paper discusses some of the critical aspects regarding the conceptual design of such an information system, and presents the actual information system developed for Braga, named SmarBRAGA.

Evaluating critical noise disturbance zones in a mid-sized city

Urban growth is continuously applying pressure over resources, infrastructures and facilities, affecting negatively the standard of living in cities. In this context, evaluating and monitoring the urban environmental quality has become a main issue particularly important when considered as a decision-support tool that contributes to more livable and sustainable cities. Viana do Castelo is a mid-sized city located on the northwest Portuguese seaside, which undertook the challenge of developing an environmental program leading to the integration in a Healthy Cities European Network. Within this program, the identification of urban noise levels and people exposure was considered a priority. The scientific toolbox adopted to develop the studies includes noise simulation models and a GIS platform. Based on traffic data and site physical characteristics, acoustical maps were created and overlaid together with the land-use-based acoustic zoning and population distribution layers. This combination was the basis for the identification of critical zones, both in terms of noise levels and people exposure to this kind of pollution. This paper aims to present the approach, including the theoretical framework, and to discuss the results of a summer scenario of noise exposure in the city center.

A mobile environmental monitoring station for sustainable cities

The aim of this paper is to present a mobile environmental monitoring station to evaluate the urban environment.The different phases of the mobile unit development are presented from its construction and operation mode for handling and sharing the data obtained. This mobile unit measures the following urban environmental parameters: environmental noise (Leq, L10 and L90), air quality (PM10, PM2.5 and Total Suspended Particles) and meteorological parameters (air temperature, relative humidity, wind speed and wind direction). This mobile unit is part of a project developed for the Portuguese city of Vila Real, called SMMART (in English “Municipal System for Monitoring Air, Noise and Traffic”). The municipality accepted the challenge of developing a platform whereby the population could be informed about the quality of the urban environment (air and noise) of the city where they live.

Contribution to atmospheric benzene concentrations of the petrol stations in a mid-sized city

In an urban environment the typical anthropogenic sources of benzene are mainly the road traffic. Other important sources are petrol stations and smallscale industries using benzene as a solvent, such as the printing industry, etc. Petrol stations are the most significant of these additional sources. Evaporative emissions from petrol station operations include contributions due to the filling underground tank operations, due to the underground tank breathing and emptying, due to vehicle refuelling operations and lastly due to spillage. The petrol stations are frequently located in populated urban areas consequently exposing the population to this kind of pollution. The present study assesses the contribution of petrol stations to the ambient benzene concentrations in a midsized city. The scientific toolbox adopted to develop the studies includes an air quality simulation model and a GIS platform. Based on the method and the rate of filling, tank configuration and gasoline properties the evaporative emissions from petrol stations are calculated. This paper aims at presenting the approach, including the theoretical framework, and at discussing the results and their role within the citys quality of life argument.