木香薷群落负离子及PM2.5浓度的时空变化及其影响因素

Spatio-temporal Variation of Negative Ions and PM2.5 Concentrations in Elsholtzia stauntonii Community

以木香薷为试材,对开花进程中、一天中不同时间及仪器进气口距植株顶部不同高度处的空气负离子、PM2.5浓度、气象因子进行测定,以期探究芳香植物木香薷群落负离子及PM2.5浓度的时空变化特征及其影响因素。结果表明:开花进程中木香薷群落负离子浓度由低到高的变化顺序依次为初花期<盛花期<末花期;开花进程中PM2.5浓度由高到低依次为初花期>盛花期>末花期;木香薷群落负离子浓度的最高值出现在17:00,最低值出现在15:00;PM2.5浓度最高值出现在11:00,最低值出现在17:00;仪器进气口距植株顶部15 cm处空气负离子浓度高于45 cm处的浓度,二者相差90.5 ion·cm-3,而不同位置处的PM2.5浓度差值仅0.6μg·m-3,即群落负离子浓度受位置变化影响较大,PM2.5浓度则受影响较小;木香薷群落负离子浓度与温度、光照强度均呈极显著负相关,而与湿度呈极显著正相关,且直线回归表明负离子浓度与各气象因子的相关性从强到弱依次为湿度>温度>光照强度;PM2.5浓度与温度呈显著负相关,与湿度、光照强度均呈正相关,且与湿度的相关性达到极显著水平。

Elsholtzia stauntonii Benth.with fragrance was used as the experimental material to measure the air negative ion concentrations,PM2.5 concentrations,temperature,humidity and light intensity at different flowering stages,different measuring times of the day and different heights from the machine′s air inlet to the top of the plants.In order to explore the temporal and spatial variation characteristic of negative ion and PM2.5 concentrations and its influencing factors in aromatic plants communities.The results showed that from low to high,the concentrations of negative ion in different flowering processes were early flowering stage<full flowering stage<late flowering stage.From high to low,the concentrations of PM2.5 in different flowering processes were early flowering stage>full flowering stage>late flowering stage.During all the day,the highest negative ion concentration appeared at 17:00.And the lowest negative ion concentration appeared at 15:00.The highest PM2.5 concentration occurred at 11:00,and the lowest at 17:00.The concentrations of negative ions at 15 cm from the machine′s air inlet to the top of the plants were higher than that at 45 cm,with a difference of 90.5 ion·cm-3.There was no significant difference in PM2.5 concentration at different positions,with a difference of only 0.6μg·m-3.The concentration of negative ions in the community was significantly negatively correlated with temperature and light intensity,and was significantly positively correlated with humidity.And linear regression shows that the correlation between negative ion concentration and various meteorological factors from strong to weak was humidity>temperature>light intensity.The concentration of PM2.5 was negatively correlated with temperature,and positively correlated with humidity and light intensity,and the correlation with humidity reached a significant level.