不同城市绿地类型对PM_(2.5)、PM_(10)以及TSP的消减效应研究

Study on the Subtractive Effect of Different Urban Green Space Types on PM_(2.5),PM_(10) and TSP

一直以来,绿地系统都是城市户外公共活动、文化展示、景观美化等功能的重要载体。此外,基于景观生态学的绿地系统研究使其生态调节功能进一步强化。作为城市的主要户外公共空间,城市绿地的空气质量关乎整个城市居民的健康,虽然已有部分研究开始初步探索城市绿地在消减空气颗粒物上的作用,但仍缺乏更加系统性的对比研究,以揭示不同绿地类型中绿地率、植物群落结构等特征对空气颗粒物的不同消减效应。本文采用定量测定的方法,对重庆市典型的绿地类型进行全年的测试分析。研究表明:绿地率最高的公园绿地对于空气颗粒物的消减率最明显;在一年四季中,TSP在夏季的消减率最高,PM_(10)的消减率春季最高,PM_(2.5)的消减率冬季最高;在不同空气颗粒物的消减率对比分析中,各种城市绿地对TSP的消减率最高,能达到15%以上,对PM_(2.5)的消减率最低,在夏季甚至出现负值。由此可见,城市绿地对总悬浮颗粒物(TSP)和粗颗粒物(PM_(10))都具有很好的消减效果,但是在对细颗粒物(PM_(2.5))的消减效果则不明显。

Green space system has always been an important carrier of urban outdoor public activities,cultural display,landscaping and other functions.In addition,the research on green space system based on landscape ecology further strengthens its ecological regulation function.As the main outdoor public space in the city,the air quality of urban green space is relevant to the health of the whole city residents.Although some studies have begun to preliminarily explore the role of urban green space in reducing air particles,there is still a lack of more systematic comparative studies to reveal the different subduction effects of different green space types,such as green rate and plant community structure,on air particles.However,with the further deterioration of the city’s air quality,the existing research has been insufficient to meet the current needs of urban development.China’s industrialization process is later than that of western countries,so its air quality problems will be as predictable as those in the West.Thus,to avoid a repeat,it is necessary to attach importance to the management of air quality while industrialization is developing rapidly.Of course,the most effective way is to control the source of pollution,but there are other things that we can do to improve air quality to a certain extent.The closest relation with this subject is the urban green space.This is a new mission of landscape architecture in the new era.It is also an important extension of this discipline.To break through the planning and design of urban green space with space as the only pursuit,more consideration should be given to different urban green spaces in improving urban air quality,especially in the reduction of air particles and other aspects of the positive role.What’more,it should be applied to the planning and design of urban green space.In this paper,the typical green space types in Chongqing are tested and analyzed by quantitative measurement.Studies have shown that:1)the reduction rate of airborne particles in park green space is the most obvious.This is because a large number of vegetation leaves have good adsorption effect,and the area of green space increases,the corresponding hard area reduced,it reduces the production of airborne particles at the source.2)In the four seasons of the year,the urban green space has the highest reduction rate in summer on TSP,the highest reduction rate in spring on PM_(10),and the highest reduction rate in winter.Thus,it can be seen,the warmer the air is,the more obvious subduction effect of vegetation on large particles.Luxuriant vegetation is conducive to the adsorption of large particles by leaves in spring and summer.In winter,the space is more open after falling leaves with better air circulation.Small particles in the air are diluted.3)In the comparative analysis of the reduction rates of different air particles,urban green space has the highest reduction rate for TSP,which can reach more than 15%,the lowest reduction rate for PM_(2.5),and even a negative value in summer.Thus,urban green space has a good effect on the reduction of total suspended particulate matter(TSP)and coarse particulate matter(PM_(10)),but the reduction effect on fine particulate matter(PM_(2.5))is not obvious.Based on the adsorption principle of vegetation on air particles,larger particles are more likely to stick to the leaves.Therefore,the adsorption of large particles is more significant,and less obvious for smaller particles.As urbanization continues to advance,cities will become denser and denser.The air quality of a city can only be achieved by its own internal green space.Through the study of different green space types to improve the regulation mechanism of urban air particulate matter,the regulation effect of different urban green space types on different air particles is clarified.It provides important theoretical guidance for urban green space planning in the future.In addition,urban green space is also an important public activity space for urban residents.It can provide necessary guidance for the urban public activity space planning and design in the aspects of activity planning,site design,activity time level surrounding environment construction and so on,with the conclusions of this study.However,the study of this paper only takes the Chongqing area with special environment as an example.It is hoped that more and more scholars will pay attention to the importance of urban green space to air quality improvement.There would be more and more follow-up studies to supplement and improve the differentiated environmental characteristics of different regions in China and their corresponding coping strategies.