夏季海淀公园内PM2.5浓度水平梯度分布规律

于2014年夏季，通过观测海淀公园不同区域沿道路不同宽度处PM2.5浓度，研究PM2.5浓度日变化规律、水平梯度分布规律、净化效益及其影响因素。结果表明，海淀公园内PM2.5浓度日变化规律呈白天低晚上高的趋势，09：00-15：00时PM2.5浓度达到国家标准Ⅱ类功能区浓度质量要求，05：00时PM2.5浓度最高。不同观测区域一定宽度范围内出现PM2.5浓度积聚，之后开始下降。总体上，海淀公园在13：00时对PM2.5浓度净化效益最显著，09：00时净化效益最差。环城高速路区域与城市主干道区域165 m以上宽度处、城市次干道区域60 m以上宽度处为正净化效益，并维持正净化效益。海淀公园内PM2.5浓度与气象因子之间相关关系表明，PM2.5浓度与平均温度、相对湿度呈显著相关，与其他气象因素没有显著相关性。

Distribution characteristics of PM2.5 concentration in Haidian Park in summer

In the summer of 2014, the diurnal variation and horizontal gradient distribution rules of PM2.5 concentration, the purification efficiency for PM2.5, and some other elements related to PM2.5 were investigated systematically via continuous monitoring of PM2.5 concentration in different areas along the roads of Haidian Park in the city of Beijing.The results indicated that diurnal variation in PM2.5 concentration was lower during the daytime and higher in the evening.The PM2.5 concentrations matched the quality requirements of National standard Ⅱ for functional areas between 09:00-15:00 and were worst at 05:00.PM2.5 concentrations increased and then began to decline in a certain scale of different area.In terms of the purification efficiency of Haidian Park for PM2.5, it was highest at 13:00 and lowest at 09:00.Both the area that is more than 165 m away from the city's beltway and main roads and the area that is more than 60 m away from the city's main roads were deemed positive purification areas, as they maintain positive purification efficiencies.The PM2.5 concentration in Haidian Park was closely related to average temperature and relative humidity and less related to some other meteorological factors.