Microclimate Effects And Human Comfort Degree Of Urban Open Spaces In Shanghai

Shanghai, because of its geographical location, usually has warm and wet air currents in summer, and with a high-temperature heat. The microclimate and human comfort of different types of open spaces has great significance on the residents travel, leisure, prevent sunlight and so on. 2010 World Expo will be held in Shanghai, the estimated total attendance of more than 70 million people. It's extremely important to study on the relationship between urban open spaces and microclimate, in addition to improve the microclimate and human comfort. Besides, air quality and pollution sources in the Expo area also have a reference value. This paper analyzes microclimate conditions of different types of urban open space on two different climatic conditions in Shanghai. The air temperature, the relative humidity, the wind speed and other microclimate parameters were measured in situ in these six types of open spaces, including the woodland, the corridor, the lawn, the square and the waterbody, analysing their effects on pleasing the feeling of human body in shanghai city. A function of Shanghai Meteorological Bureau, the calculation formula between air temperature, relative humidity and the human comfort index, was introduced to describe the human feelings quantificationally . The concentration of Respirable Particles (PM₁₀) was monitored the various types of urban open space in Expo site, and similar types out of it simultaneously. Then investigation of Expo and the surrounding area researched on sources of pollution, including travel and industrial chimneys flow situation. The purpose of the study is to identify different types of open space to small climatic conditions, air quality and human comfort regulation. We that the highest priority should be given to the green open spaces especially the woodland and the corridor in the designing of the public areas for urban open space and then apply to Shanghai Expo 2010 site. To suggest how to put the green, water and other public space into the design of open space reasonablely for the Expo area planning and construction. The main results of the study as follow:1. Through the analysis and comparison, green vegetation was generally better than non-covered open space types. The cooling effects of woodland and corridor were obvious on two weather conditions. Besides, waterbody had the best cooling effect on the weather condition 1. In the hot cases (weather condition 2), the cooling effect of woodland was best. In conditions 2 (hotter) , the waterbody humidify air was most effective. The average speed of wind of woodland was usually the lowest one among all types of space, while riverside was fastest. The ground temperature depends mainly on the acceptance of solar radiation. That of the woodland and the corriodor with vegetation cover was lower. By analysing correlation coefficient between non-climate and climate factors, we get the results that correlation varied in different space types. The result showed that the air temperature of the woodland interacted respectively between ground temperature, solar radiation, the coverage of shrub and the heigh of the tree canopy. In corridor, the air temperature correlated with humidity, ground temperature and the width of the corridor; then the ground temperature had correlation with solar radiation, coverage of trees and width of corridor. As for the lawn, air temperature has remarkable correlation with ground temperature and the specie of grass; the ground temperature had remarkable correlation with solar radiation. Air temperature of the square had significant correlation with the average speed of wind and the acreage of the square, and its air humidity correlated with ground temperature and solar radiation. The air temperature and humidity of waterbody mainly correlated with speed and direction of wind.2. Human comfort index of different urban open spaces were different. Body's feeling of the woodland, the corriodor and the waterbody were more comfortable in hot summer. And most people were discomfortable on the square. In weather conditions 1, it's seven class by meteorological standard, and body feeling is tepid. Human comfort of all types space were relatively close to average. However, the waterbody, the riverside and the corridor are more comfortable than others. In weather condition 2, which weather grading standards reached eight, then human-feeling is very hot.The comfort of all types space is worse than condition 1. In high temperatures, the woodland and waterbody were more comfortable. As the result the capacity of regulating human comfort of woodland and waterbody were still very prominent with lowest D.I. values. The result of correlation analysis indicated that the structure of space had impact on human comfort. Human comfort of the woodland had correlation with the coverage of shrub and the height of arbor canopy. Width of corridor and height of the tree canopy could significantly affect the human body comfort. Grass species also has very significant effect the grassplot's human comfort. The area of the square and the waterbody was respectively correlated with their human comfort.3. The concentration of dust particles of demolition area in the Expo site was highest. In addition, the concentration of exposed space including the square and grassplot without vegetation cover were higher. The woodland, the corridor, the riverside and the waterbody had less dust particulate. Because of open and large number of sand on surface, the demolition area had the highest concentration of PM₁₀. Green plants had great capability to delay dust, and waterbody effectively combines and absorbs of dust, and all these could benefit air purification. The urban pollution (PM₁₀) source was mainly fuel combustion, vehicle exhaust, construction and so on. The investigation on Expo and surrounding area found that the roads aroud Expo region had the higher vehicle flow, then Lupu and Nanpu Bridge linked Pudong district with Puxi reached a peak. There were 35 industrial chimneys, and 5 chimneys over 70 meters high. Through verified, the majority of the chimney was using then.