昆明市不透水表面扩张与PM2.5质量浓度变化相关性分析

为分析城市化进程导致的城市生态环境问题，采用不透水表面覆盖率（impervious surface coverage，ISC）作为宏观地理指标表征昆明市城市化水平，以ρ（PM_2.5）反映城市化进程带来的大气环境问题，基于不同空间尺度和空间数理统计研究了ISC与ρ（PM_2.5）的对应关系.结果表明:2000-2015年，昆明ISC从9.36%增至16.37%，ρ（PM_2.5）年均值从17.12μg/m3增至28.63μg/m3，并且二者空间分布总体一致.从乡镇尺度分析，乡镇ρ（PM_2.5）和ISC具有显著空间自相关性，二者2015年Moran's I指数分别为0.58和0.29（P < 0.001），具有显著正相关性（R2=0.803，P < 0.001）.当乡镇ISC>5%时，有58.14%（25/43）的乡镇已污染ρ（PM_2.5）>25μg/m3]；当乡镇ISC>10%时，有71.43%（25/35）的乡镇已污染；当乡镇ISC>25%时，有100%（26/26）的乡镇处于污染状态；但当乡镇ISC < 5%时，所有乡镇的ρ（PM_2.5）都低于25μg/m3.从站点尺度分析，所有站点旱季比雨季污染严重；主城区站点（ISC高）比城郊区站点（ISC低）污染严重，其中前者季节变化为冬天>春天>秋天>夏天，后者为春天>冬天>夏天>秋天；站点缓冲区ISC与ρ（PM_2.5）的相关性显著（R2=0.893，P < 0.001）.研究显示，未来中国新型城市化建设中应当考虑城市不透水表面比例和空间分布，保证新型城市拥有足够的绿色空间，建设生态城市. 

Association Between Impervious Surface and PM2.5 Concentrations in Kunming,China

In order to understand the effects of urbanization on the Earth's ecosystem, the impervious surface coverage(ISC) has been recognized as a geographical indicator to reflect the intensity of human development activities with rapid urbanization.The PM_2.5 pollution is used to indicate air quality.The relationship between ISC and PM_2.5 pollution was explored with two levels based on spatial statistics.From 2000 to 2015, the ISC in Kunming increased from 9.36% to 16.37%, while the PM_2.5 concentration increased from 17.12 μg/m3 to 28.63 μg/m3.The spatial distribution of the PM_2.5 aggravation was consistent with the impervious surface expansion in Kunming.The growth of ISC in the southeast(11.56 to 25.78%) was greater than that in the northwest(2.12 to 5.15%), and the increase of PM_2.5 concentration in the southeast(21.37 to 36.75 μg/m3) was also greater than that in the northwest(4.56 to 10.65 μg/m3).The relationship between ISC and PM_2.5 concentrations was explored at the town level and the station level.The impervious surface and the PM_2.5 pollution in Kunming both had significant spatial autocorrelation between the towns with Moran's Index of 0.29 and 0.58(P < 0.001), respectively.For towns' ISC greater than 5%:58.14%(25/43) of the towns were degraded; for ISC > 10%:71.43%(25/35) of the towns were degraded; for ISC > 25%:100%(26/26) of the towns were degraded.In contrast, for towns with ISC < 5%:none of the towns were degraded.With the least square method, the results showed a good fitting(R2=0.803, P < 0.001) between the towns' ISC and PM_2.5 concentrations.Moreover, at the station level, the relationship between ISC of the stations' buffer(2000 m) and PM_2.5 concentrations were explored(R2=0.893, P < 0.001) with Pearson's Correlation, indicating ISC has strong association with PM_2.5 concentration.Thus, the proportion and spatial distribution of impervious surface should be considered in National New-Type Urbanization Development, making cities surrounded by enough green belt and water areas.