Urban green areas have the potential to attenuate some of the negative effects of urbanisation, making cities a more pleasant place to live in. In addition to aesthetic value, green spaces improve air quality, reduce noise levels and generate more comfortable micro-climatic conditions, among other benefits, contributing to urban quality of life. GreenUrbe (POCI/AMB/59174/2004) – The Impacts of Green Spaces on Urban Environmental Quality – is a three year research project, started in October 2005 and aims to assess the impact of green spaces on urban environmental quality (air quality, noise and micro-climatic conditions) and social well-being, in order to formulate recommendations regarding green spaces design, as it is an essential activity in urban planning, using Bragança (Portugal) as the case study. In order to achieve these objectives an extensive fieldwork is being carried out at an urban area, involving measurements of meteorological parameters, passive sampling of ozone, nitrogen dioxide and COVs, continuous measurements of particulate matter and ozone, environmental noise measurements, experimental designs to evaluate how much vegetation interfere with noise propagation and noise absorption, haze evaluation by means of Small Format Aerial Photography (SFAP) and a survey on population attitudes and perceptions towards the overall urban green spaces. In this article, emphasis will be given to the methodological aspects and to the first results of the project with regards to urban green structure analysis and quantitative evaluation of environmental noise, air quality and climate comfort at Bragança city.