Previous studies on negative air ion (NAI), an important index for evaluating atmospheric quality, has been focused on field observation, and less on NAI under controlled condition. In this study, the NAI concentrations of different individual abundance of Liquidambar formosana and Taxus wallichiana were continuously monitored under the same climatic conditions in Hushan Experimental Base of Qianjiangyuan Forest Ecosystem Research Station, Zhejiang Province from September to October 2018. Changes of NAI concentration were monitored under different levels of air temperature and relative humidity to explore the effects of forest vegetation and meteorological factors on NAI. The results showed that both species significantly increased the NAI concentration. Plant abundance was positively correlated with the NAI concentration, and the relationship between them fitted the quadratic function with the plant abundance ranging from 0 to 50. The fitting equations for L. formosana and T. wallichiana were as follows: y=-0.0484x2+4.7005x+345.7 (R2=0.62), y=-0.0207x2+1.9189x+365.91 (R2=0.34). There was a significant positive correlation between NAI concentration and air temperature in the range of 5-30 ℃ with a fitting equation of y=0.4139x2-9.2229x+89.919 (R2=0.92). The NAI concentration and the relative humidity of air in the range of 56%-87% were positively correlated with a fitting equation of y=3.6508e0.0526x(R2=0.94).
空气负离子(NAI)作为评价大气环境质量的重要指标,以往研究侧重于野外观测试验,关于控制条件下的NAI研究甚少.本研究于2018年9--10月在浙江钱江源森林生态站杭州虎山试验基地人工气候室内控制相同气候条件下,对枫香和红豆杉不同植株数量的NAI浓度进行连续定位监测;在其他条件一致的情况下,分别设置空气温度和相对湿度的不同梯度,监测NAI浓度变化,旨在为探究森林植被和气象因子对NAI作用机理提供理论依据.结果表明: 两种植物显著提高NAI浓度.植株数量与NAI浓度呈极显著正相关,二者在0~50株范围内最符合二次函数关系,枫香、红豆杉的NAI浓度与株数的拟合方程分别为y=-0.0484x2+4.7005x+345.7(R2=0.62)、y=-0.0207x2+1.9189x+365.91(R2=0.34).NAI浓度与空气温度在5~30 ℃范围内呈极显著正相关,拟合方程为y=0.4139x2-9.2229x+89.919(R2=0.92).NAI浓度与空气相对湿度在56％~87％范围内呈极显著正相关,拟合方程为y=3.6508e0.0526x(R2=0.94).
Keywords: air temperature; negative air ion; phytotron; plant number; relative humidity of air; subtropical region.