摘要: |
在城市化快速进程的背景下,城市
街区PM2.5污染日益严重,本文选取哈尔滨
在不同季节的典型街谷空间,对以叶面积密
度(LA D)、叶面积指数(LAI)为实测要素
的绿色界面指数以及PM2.5浓度进行实测对
比研究。通过对实测数据的分析和挖掘,最
终得出如下结论:首先,典型街谷空间PM2.5
时段浓度呈现上午比下午平均高37.75%,冬
季比夏季高4.7倍的特征;其次,街谷空间的
灌木界面对PM2.5浓度场平均积极贡献率为
18.62%;最后,对PM2.5的衰减率与实测街
谷绿色界面的叶面积密度(LAD)与叶面积
指数(LAI)进行相关性分析,结果显示街谷
绿色界面对PM2.5浓度的衰减作用与叶面积
密度(LAD)呈显著负相关关系,与叶面积指
数(LAI)的相关性程度较弱。 |
关键词: 街谷空间 PM2.5浓度分布场 绿
色界面指数 |
DOI:10.13791/j.cnki.hsfwest.20190413 |
分类号: |
基金项目:国家自然科学基金面上项目(51478136) |
|
Correlation Between PM2.5 Distribution Field and Green Interface Index in Typical Street Canyon of Harbin |
LI Guanghao,YAO Mengxue,DONG Wei
|
Abstract: |
Under the background of the acceleration of urbanization in China, the urban
composite carrying capacity is increasing, and the urban environment such as air and water
pollution is beginning to appear gradually. In some northern Chinese cities, due to its special
severe cold climate, its main urban environmental pollutants are PM2.5. As an important part
of the urban underlying surface, the special narrow and long form affects the air flow to form
a special wind field, and thus forming a corresponding PM2.5 concentration field. As a “soft
interface” of street space, plants are considered to be one of the most appropriate ways to reduce
the concentration of air pollutants, and are widely used in the study of urban street and valley
environment. This paper selects the typical street space of Harbin as the research object, and
studies the influential mechanism of the green interface in the valley on the concentration field of
PM2.5. In this paper, six typical Harbin typical street valleys with an aspect ratio of about 1.0 are
selected. The concentration of PM2.5, leaf area index and leaf area density in six street valleys
are measured in four seasons to analyze the density of different leaf areas. The influence of leaf
area index and planting interval on the distribution field of concentration in PM2.5, determines
the core influencing factors of PM2.5 distribution field, and establishes the concentration
database of PM2.5 in different seasons. Through the analysis and excavation of the measured
data, the following conclusions are drawn: the concentration of PM2.5 in the morning of typical
street space indicates an average of 37.75% higher than the afternoon, and 4.7 times higher than
the summer in winter.
Considering twelve o’clock as the dividing line, the average concentration of the morning
and afternoon of the six streets is compared. Except for the morning concentration of the
company street (Fengqi Street-Railway Section), which is 0.54% lower than the afternoon
concentration, the morning concentration of other streets is higher than the afternoon
concentration. The values are: 62.77% of Company Street, 38.02% of Customs Street, 45.44% of
Fuhua Sidao Street, 39.19% of Shangjiashu Street and 3.36% of Postal Street.
According to the seasonal distribution of the average concentration of PM2.5, the
concentration in PM2.5 of the six streets shows the highest in winter and the lowest in summer.
The average concentration of PM2.5 in the northwest-southeast Sanjie Street in winter is 4.73
times of that in summer. The average concentration of PM2.5 in the three northeast-southwest
streets in winter is 4.76 times of that in summer.Secondly, the shrub band in the street space has
positive contribution with an average rate of 18.62% to the PM2.5 concentration field.
There are two streets in the sample containing shrubs, which are the northwest-southeastoriented
Customs Street (Post Street-Manzhouli Street) and the northeast-southwest-oriented Post Street (Customs Street-Beijing Section). Compared with the two measuring points of shrubs and street trees, the peaks of concentration in
terms of the PM2.5 of the four seasons are smaller than the measuring points of the street trees. The specific values are: Customs Street (Post Street-
Manzhouli Street), 40.43% in winter, 4.92% in spring, 20.97% in summer, 19.54% in autumn. Post Street (Customs Street - Beijing Street) 5.74% in
winter, 3.76% in spring, 36.01% in summer and 17.62% in autumn. It can be seen that the shrub plays a positive role in the reduction of concentration
in PM2.5.
Finally, the PM2.5 concentration distribution field shows a significant negative correlation with leaf area density (LAD) in the green interface,
while it is significantly correlated with another parameter leaf area index (LAI). Correlation analysis between leaf area density (LAD) and leaf area
index (LAI) and PM2.5 attenuation coefficient (PMDA) data is performed by SPSS. The results show that the correlation coefficient between PMDA
and LAD is 0.04 (less than the significant correlation standard threshold of 0.05), showing a significant negative correlation and the correlation
coefficient is -0.598. Meanwhile, the correlation coefficient with LAI is 0.082, showing no significant correlation between the two. Therefore, in the
study of the green interface and PM2.5 concentration field, it is more appropriate to use the leaf area density (LAD) with greater correlation weight
as the green interface index |
Key words: Street Canyon Concentration Distribution Field of PM2.5 Green Interface Index |