基于GIS的烟台主城区PM_2.5时空分布特征研究
GIS-Based Study on Spatial-Temporal Distribution Characteristics of PM_2.5 in Yantai Main Urban Area

利用烟台市6个环境监测站点2019~2021年三年的PM_2.5监测数据研究其时空分布特征。结果表明：1) 在时间尺度上，三年的PM_2.5浓度年均值呈逐年下降趋势，且2020年和2021年的年均值均低于二级标准限值；从季节变化来看，三年的PM_2.5浓度由高到低依次为冬季、春季、秋季和夏季；从月变化来看，三年PM_2.5浓度基本呈现“U”型曲线，较高值一般出现在1月和12月，较低值出现在7~8月；从日变化来看，不同季节PM_2.5日变化基本都表现为双峰型曲线，尤其在冬季和春季双峰型曲线表现更为明显。第一个峰值出现时间大概在上午9:00~11:00，第二个峰值在晚上21:00~23:00，出现峰值的时间4个季节并不相同，夏季最早，冬季最晚，春季和秋季相差不大。2) 空间尺度上来看：PM_2.5浓度的空间分布特征整体来说是西部要高于东部，污染较高的地区主要为福山区，牟平区和莱山区污染较轻，但是不同年份，不同季节，PM_2.5浓度的空间分布特征又具有一定的差异性，其中空间差异率最高的季节为夏季。
The spatial-temporal distribution characteristics of PM_2.5 were studied using the monitoring data of six environmental monitoring stations in Yantai from 2019 to 2021. The result shows that: 1) On the time scale, the annual mean of PM_2.5 concentration showed a downward trend year by year, and the annual mean in 2020 and 2021 were lower than the secondary standard limit; from the perspective of seasonal changes, the PM_2.5 concentration during the three years was from high to low in winter, spring, autumn and summer; from the monthly change point of view, the three-year PM_2.5 concentration basically presents a “U-shaped” curve, with the higher value generally appearing in January and December, and the lower value appearing in July to August; from the perspective of diurnal variation, the diurnal variation of PM_2.5 in different seasons basically presents a bimodal curve, especially in winter and spring. The first peak occurred at about 9:00~11:00 in the morning, and the second peak occurred at 21:00~23:00 in the evening. The peak time was different in the four seasons, the earliest in summer and the latest in winter, and there was little difference between spring and autumn. 2) On the spatial scale, the spatial distribution characteristics of PM_2.5 concentration are generally higher in the west than in the east. Fushan is the most polluted area, while Muping and Laishan are less polluted. However, the spatial distribution characteristics of PM_2.5 concentration are different in different years and seasons, and the season with the highest spatial difference rate is summer.