呼和浩特市空气质量状况及与气象因子的相关性分析

Correlations between air quality status and meteorological factors in Hohhot city

利用2015年1月1日—2016年12月27日呼和浩特市环境监测中心污染物浓度数据和同期自动气象观测站逐日气象数据,对空气质量时间分布状况进行评价,分时段分析空气质量指数与气象因子相关性显著水平。结果表明:研究期内,二级(良)天气是呼和浩特市主要空气质量特征,占总日数的61.6%;主要污染物为PM10,贡献率达40.9%;大部分污染物年内分布呈双峰型曲线,波谷出现在6-8月;四季中,以冬季污染最为严重,春秋季次之,夏季空气质量相对较好。气象因子对大部分污染物IAQI有显著影响,气温和日照时数与SO_2、NO_2、PM10、CO与PM_(2.5)的IAQI呈极显著负相关,与O_3的IAQI呈极显著正相关关系;相对湿度对NO_2、CO、O_3与PM_(2.5)浓度影响显著;除与O_3的IAQI相关性较差外,降水与风速与其他5种污染物均呈极显著负相关关系。气象因子对AQI影响在不同时段存在明显差异,特别是供暖期与非供暖期。影响AQI的主要气象因子冬季为气温、相对湿度、风速和日照,春季为气温、最大风速和日照,夏季为气温、相对湿度、降水和日照,秋季为气温、降水和风速,供暖期为相对湿度、风速和日照,非供暖期为气温、降水、最大风速和日照。供暖期气温对AQI的影响是通过影响燃煤量来体现的。

Based on the air pollutants monitoring and ground meteorological data,temporal distribution characteristics of the ambient air quality during 2015-2016 in Hohhot city were evaluated,and the relationships between the air quality index（ AQI） and ground meteorological factors were discussed according to different periods. The results indicated that Ⅱ-air-quality primarily occurred in Hohhot,accounting for 61. 6% of the total number of days. The main pollutant was PM10,the contribution rate was of 40. 9%. Distributions of most pollutants showed bimodal,and the trough appeared in June-August. In four seasons,the most serious pollution occurred in winter; air quality in summer was relatively better. Meteorological factor had significant influence on most of the pollutants IAQI,Temperature and sunshine duration very and significantly negatively correlated with SO_2,NO_2,PM10,CO,PM_（2.5） IAQI,very significantly positively correlated with O_3 IAQI. Relative humidity affected the NO_2,CO,O_3 and PM_（2.5） concentrations significantly. Precipitation and wind speed very significantly negatively correlated with other five pollutants except the O_3 IAQI. The impact of meteorological factors on AQI was existed obvious difference in different periods,especially in the heating period and non-heating period.Wind speed,temperature,sunshine and rainfall were the key meteorological factors that affected the AQI significantly. The main meteorological factors affecting the AQI were air temperature,relative humidity,wind speed and sunshine in winter,air temperature,maximum wind speed and sunshine in spring,air temperature,relative humidity,precipitation and sunshine in summer,air temperature,precipitation and wind speed in autumn,relative humidity,wind speed and sunshine during heating period,air temperature,precipitation,maximum wind speed and sunshine duration during non-heating period. Influence of air temperature on the AQI in heating period was reflected by influencing the coal consumption.