雁荡山杉木林夏季空气颗粒物的垂直空间变化特征

Variation of Particle Matters in Different Vertical Heights of Cunninghamia lanceolata Forest in Yandangshan

[目的]研究森林空气颗粒物的不同高度垂直空间变化特征,为森林康养环境利用提供理论依据。[方法]于2017年5月对温州雁荡山杉木林林下(人体高度1.5m)、林冠中部(6m)及林冠顶部(12m)3个高度的空气颗粒物质量浓度(TSP、PM10、PM2.5、PM1.0)进行同步昼夜24h监测,分析空气颗粒物质量浓度的空间变化规律。[结果]表明:(1)杉木林垂直空间不同粒径颗粒物的质量浓度存在差异,总颗粒物质量浓度与细颗粒物(<2.5μm)质量浓度在3种高度差异显著,均为林冠层最低;(2)3种不同高度的TSP、PM10质量浓度日均值均达到二类环境功能区质量要求(300、150μg·m^-3),其中,林冠层的TSP日均值达到一类环境功能区质量要求(120μg·m^-3);(3)不同高度各粒径空气颗粒物日变化规律大体一致,均表现为白天低,夜间高;(4)不同垂直高度空气颗粒物质量浓度,白天为林冠层最低;夜间为TSP质量浓度各垂直高度差别不大,PM10、PM2.5与PM1质量浓度总体为在人体高度较低;(5)各粒径空气颗粒物与露点温度极显著正相关,与气压极显著负相关,其中,PM2.5质量浓度与2项环境因子相关系数最大;除TSP外,其余颗粒物质量浓度与温度、最大风速极显著正相关,与相对湿度极显著负相关,各气象因子共同影响空气颗粒物质量浓度。[结论]通过对结果的综合分析,温州雁荡山杉木林环境林冠层为康养游憩最佳高度,最适宜白天出行。

[Objective] To study the variation of air particles with different vertical heights and provide theoretical basis for the construction and utilization of forest therapy.[Method] In this paper,the mass concentrations of TSP,PM10,PM2.5,and PM1 at the height of human body (1.5 m),the middle of forest canopy (6m),the canopy upper layer (12m) of Cunninghamia lanceolata forest were observed for 24 hours in summer of 2017 with a cloudy weather in the Yandangshan of Wenzhou.[Result]1.The mass concentrations of different-sized particle matters varied in different heights.There was a significant difference between the TSP and PM2.5,that of the middle of forest canopy were all the lowest in three heights.2.The daily mean mass concentrations of TSP and PM10 in the three heights were all reached the grad-Ⅱof national standard for urbanized area ambient air quality,and the concentrations of TSP in forest canopy reached the standard grade-Ⅰ.3.During the observation period,the concentrations of particle matter in different heights were higher at night,and lower in the daytime.4.The middle of canopy (H2) of air particulate matter in different vertical height was the lowest in the day time;there was no significant difference in TSP mass concentration in three heights,the mass concentrations of PM10,PM2.5 and PM1 were generally low in human height at night.5.The concentrations of four kinds of particles were significantly positively correlated with dew temperature and negatively correlated with air pressure.The correlation coefficient between PM2.5 and both factors was the largest.The concentrations of PM10,PM2.5,and PM1 were significantly positively correlated with temperature as well as maximum wind velocity,and negatively correlated with relative humidity.Every meteorological factor affected the mass concentration of air particles.[Conclusion] The middle of canopy is the best height for recreation in C.lanceolata forest in the Yandangshan of Wenzhou.It is most suitable for daytime travel.