| Streets, parks, squares and other urban public spaces are the most popular places for shopping, walking, gathering and other outdoor activities, and its environmental quality and comfort have drawn more and more attention. In the past, the research on the urban public space’s micro environment is more focused on the analysis the characteristics of the thermal environment; the research on the air quality and noise pollution is few. It is very important to study the micro environmental quality of urban public space and quantitatively evaluate its thermal environment, air quality and noise level, then put forward a comprehensive evaluation method for environmental quality.In the summer of 2015 and the spring of 2016, the thermal environment, air quality and noise levels were investigated at five measuring points in Wuyi Square and Meixi lake in Changsha, China. Based on field survey and questionnaire survey: total of 402 valid questionnaires were delivered. Firstly, a comprehensive evaluation method for urban public space’s micro environmental quality was introduced, including the evaluation index selection and classification method. Secondly, the environment of public space in spring and summer, such as thermal environment, air quality and noise level, was evaluated and analyzed. Then, the paper came up with the multiple index weight calculation method in analysis and evaluation the comprehensive environmental quality in spring and summer for public space. Finally, based on the questionnaire survey, the parameters of this public space subjects sensation vote and expected vote were analyzed, taking the affect of comfort of the physiological factors and psychological factors into account, and put forward measures and suggestions to improve urban public space micro environment.The results show that the range of PET value in summer public space is 30℃ to 55℃, and the corresponding level is the first level, meaning people feel extremely uncomfortable; the PET value range in spring is 9℃ to 29℃, the thermal sensation changes frequently. Concentration of pollutants in spring is higher than in summer, and concentration in the morning is higher than in the afternoon; in the most time of summer, the air quality level is at "good" rating level, while it is the third level in most time of spring, meaning "light pollution". Noise level is the second level in summer, which usually is not an acceptable level; the level rank of Wuyi square is the second level and Meixi lake noise level is third level in the spring. The weight of each index(0.29,0.68,0.04) was obtained by entropy method; the weight of each index(0.27,0.59,0.14) was obtained by using the variation coefficient method; the weight of each index(0.52,0.31,0.17) was obtained by the subjective weighting method; according to the combination weighting method, the weight of each index is 0.40,0.47,0.13, where the λ is 0.5.The public space comprehensive environmental quality in spring is better than that in summer, the comprehensive environment quality of Meixi lake is better than that of Wuyi square area. The subjects feel comfortable in the urban environment in spring, but they also want air quality and noise levels to be improved. In addition the proportion of subjects who feel comfortable at Meixi lake is higher than that in Wuyi Square; about 33% of subjects choose clothes, addition and subtraction, glove, scarf, drink or eat the fast and direct way to increase their own comfort, 92% of subjects prefer natural environment; Gender, BMI(Body Mass Index), travel purpose, outdoor activity time and familiarity with public space have a certain influence on the comfort of human body. Gender, BMI, travel purpose, outdoor activity time and familiarity with public space have a certain influence on the comfort of human body. The comprehensive environmental assessment method proposed in this paper can not only evaluate the overall environmental quality of a public space, but also provide reference for urban planning, design as well as operation. |
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