济南市降尘通量时空分布特征研究

Study on Spatial and Temporal Distribution of Dust-fall Flux in Jinan City

为研究济南市大气降尘的变化规律,探讨降尘的气象影响因素,于2017年12月-2018年12月期间,在济南市区及县区共21个采样点采集了降尘样品,研究了济南市降尘通量的时空分布特征,分析了降尘通量与环境空气中PM10和PM2.5的相关性,并通过构造降尘通量和各气象要素(气温、相对湿度和风速)的标准化回归方程,计算了各气象因子对大气降尘变化的相对贡献率。结果表明:2018年济南市降尘通量表现为先升高再降低的变化趋势,春季高秋季低,降尘通量在4月到达全年峰值(11.97t·km^-2·30d^-1),超过生态环境部2018年首次颁布的大气降尘国家考核目标标准(9t·km^-2·30d^-1)的33%,且市区的降尘通量稍高于县区的降尘通量;21个采样点中,只有紧邻工业园区的蓝翔技校和受道路施工影响的建筑大学两个采样点降尘通量超标,分别为9.56t·km^-2·30d^-1和10.18t·km^-2·30d^-1,其他采样点均不超标,跑马岭的降尘通量最小,为4.71t·km^-2·30d^-1,济南市区各行政区降尘通量变化较大,县区差异较小;降尘通量与环境空气中PM10、PM2.5的质量浓度相关性均不高,说明降尘对环境空气的直接影响不大,泉城广场点位和清洁对照点位的降尘对环境空气影响高于其他点位,应加大措施控制降尘;3种气象因素中风速对降尘通量的相对贡献率达到50%以上,济南市大气降尘通量主要受风速的影响,风速较大时,降尘通量增加,县区采样点的降尘通量还与湿度有一定负相关,气温对降尘通量的影响很小。

To study the changing law of dust flux in Jinan and to investigate the meteorological factors affecting the atmospheric dust, dust-fall samples were collected at 21 sampling sites in both urban district and counties of Jinan from December 2017 to December 2018. The spatial and temporal distribution of dust flux in Jinan was studied and the correlation between dust flux and PM10 and PM2.5 was analyzed. By constructing the standardized regression equation of the dust flux and meteorological factors (including temperature, relative humidity and wind speed), the relative contribution rate of each meteorological factor to atmospheric dust flux was calculated. The dust flux of Jinan in 2018 was increased and then decreased, and it was higher in spring and lower in autumn, the annual peak was observed in April (11.97 t·km^-2·30d^-1), of which was 33% higher than the dust emission standard (9 t·km^-2·30d^-1) issued for the first time by Ministry of Ecology and Environment of the People’s Republic of China in 2018. The dust flux in the urban area was slightly higher than that in the county area. In addition, the dust flux of the two among the 21 sampling sites, Lanxiang Technical School (9.56 t·km^-2·30d^-1) adjacent to the industrial park and Shandong Jianzhu University (10.18 t·km^-2·30d^-1) affected by road construction, exceeded the dust emission standard, and the lowest dust flux was observed in Paomaling (4.71 t·km^-2·30d^-1). It showed great differences of dust flux among the different urban districts, while the difference among counties was small. The correlation between dust flux and the mass concentration of PM10 and PM2.5 in the ambient air was low, indicating that dust has little direct influence on the ambient air. The dust at the Quancheng Square and the clean control site showed higher impact on the ambient air than other sites, suggesting a need for strengthening dust fall controlling. The atmospheric dust flux of Jinan was mainly affected by wind speed among the three meteorological factors, and it reached more than 50%, with faster wind speed higher dust flux. Additionally, the dust flux in the county area was negatively correlated with the humidity, while air temperature played a negligible effect on dust flux.