济南PM2.5质量浓度与气象条件相关性初步研究

A preliminary study on the correlation between PM2.5 mass concentration and meteorological conditions in Jinan

通过对济南2013年12月—2018年2月PM2.5质量浓度数据分析得出,PM2.5质量浓度平均和最大值均为冬季最高,春秋季次之,夏季最低;PM2.5质量浓度值1月和12月最高,8月最低;其质量浓度呈明显的逐年递减趋势。在不同风向上PM2.5质量浓度存在显著差异性,在N风向和ESE(盛行)风向上均出现了质量浓度较大值,一方面与污染物的异地输送有关,另一方面与济南的特殊地形有关。研究表明,无论污染源在山脉的背风侧还是迎风侧,都很容易导致高浓度污染;尤其在冬季,山脉地形还会加重逆温影响,使污染程度加重。通过相关性研究发现,冬季、春季和秋季,PM2.5质量浓度与相对湿度和平均总云量均呈正相关,与日照时数及其距平呈负相关;冬季,PM2.5质量浓度与平均气温及其距平以及最高、最低气温均呈正相关,与平均、最高、最低气压均呈负相关;春季和秋季,PM2.5质量浓度与气温距平值呈正相关;夏季和秋季,PM2.5质量浓度与日降水量呈负相关,而且随着雨强的增大,对PM2.5的洗消作用越显著。上述变量间相关性均通过了P≤0.01显著性检验。

According to the data analysis of PM2.5 mass concentration from December 2013 to February 2018 in Jinan,the mean and maximum PM2.5 mass concentration in winter are the highest,followed by that in spring and autumn,and the lowest is in summer;PM2.5 mass concentration is the highest in January and December and the lowest in August;the mass concentration shows a significant decreasing trend year by year.There are significant differences in PM2.5 mass concentration under different wind directions and higher mass concentration appears in N and ESE(prevailing)wind direction,which,on the one hand,is related to the regional transport of pollutants,and on the other hand,is related to the special topography of Jinan.The study shows whether the pollution source is on the leeward or the windward side,it is likely to cause high-concentration pollution;especially in winter,the topography of mountain will also intensify the impact of temperature inversion,aggravating the pollution.The correlation study finds in winter,spring,and autumn,PM2.5 mass concentration is positively correlated with both relative humidity and mean total cloud cover,while negatively correlated with sunshine duration and its anomaly;in winter,it is positively correlated with mean temperature and its anomaly,maximum temperature,and minimum temperature,while negatively correlated with mean,maximum,and minimum atmospheric pressure;in spring and autumn,it is positively correlated with temperature anomaly;in summer and autumn,it is negatively correlated with daily precipitation,and as rainfall intensity increases,the washing effect on PM2.5 is more significant.The correlation among the above variables all passes the significance test of p equal to or lower than 0.01.