福州市CO时空分布特征与影响因素

Temporal and Spatial Variation Characteristics and the Impact Factors of CO in Fuzhou

国家环境保护部2012年修订的"环境空气质量标准"将CO列入环境空气污染物基本项目,因预报业务迫切要求构建福建省重点城市福州CO的预报概念模型。利用2011─2013年福州市6个环境空气国控点CO小时质量浓度观测资料,结合NO2、O3等污染物浓度、气象常规观测资料以及通过聚类分析法将天气进行环流分型,分析CO的时空分布规律,与其它污染物浓度的相关性以及天气形势、气象要素等对CO质量浓度变化的影响。结果表明,福州CO年平均质量浓度的高值出现在工业源较多、交通源密集的监测点;市区浓度高于郊区和高山站点,24 h平均质量浓度没有出现过超标现象。冬季平均质量浓度最高,其次是春季、秋季,夏季最低是冬季的0.68倍;峰值出现在1月和4月,冬半年CO质量浓度整体高于夏半年。日分布高峰出现在7:00─10:00和17:00─20:00,低谷出现在13:00─16:00,白天浓度值波动大,夜间稳定处于低值区。CO与NO2质量浓度呈现显著的正相关性,秋季最高相关系数0.658;与O3质量浓度呈现反相关性(夏季除外)。CO质量浓度出现相对高值的天气型依次是锋前暖区>高压后部>切变、高空槽>地面倒槽;出现相对低值的天气型依次是副热带高压<台风(热带辐合带)外围<台风(热带辐合带)<副热带高压边缘<高压脊<高压底部。大气扩散条件的好坏、光化学作用是否明显以及风速的大小是决定CO质量浓度高低的主要因素,与降水量关系不大。

CO was listed in basic ambient air pollution items in “ambient air quality standards” revised by Ministry of Environmental protection of the People’s Republic of China in 2012. For forecast operation, there’s a pressing need to establish the forecast conceptual model of CO for Fuzhou, which is the key city in Fujian. The temporal and spatial variation characteristics of CO,the relationship between CO and other pollutants, and the effect of synoptic situations and meteorological factors on CO were analyzed using observation data in Fuzhou. The pollutant parameters observed from 2011 to 2013 included mass concentrations of CO, NO2 and O3 from 6 environmental monitoring points, and conventional meteorological observation data and synoptic situations recorded by cluster analysis method.The results showed that high annual average mass concentration of CO was in the environmental monitoring point where had more industrial and traffic sources. Mass concentration was higher in urban monitoring points than that in suburb and mountain. The 24-hour average mass concentration didn’t exceed standard. Quarterly average mass concentration was highest in winter, and then in spring and autumn, lowest in summer, which was 0.68 times that in winter. The highest mass concentration was in January and April, and it was higher in winter half year than that in summer half year. The highest mass concentration in a day appeared at 7：00─10：00 and 17：00─20：00, while lowest at 13：00─16：00. The mass concentration fluctuated in the daytime, while kept low and steady-going in the night. There was a significant positive correlation between the mass concentration of CO and NO2, and the correlation coefficient was highest in autumn 0.658, and there was a negative correlation between the mass concentration of CO and O3 （except in summer）. Higher mass concentration of CO was in the pre frontal warm sector, posterior of high pressure, shear and upper trough, ground inverse trough, successively. Lower mass concentration of CO was in the subtropical high, outside of typhoon （intertropical convergence zone）, typhoon （intertropical convergence zone）, near the subtropical high, pressure ridge, bottom of high pressure, successively. Atmospheric diffusion conditions, photochemical effect, and wind speed were the major factors of the mass concentration of CO, while rainfall wasn’t an important factor.