北京松山国家级自然保护区空气负离子浓度时间变化及空气质量评价

Temporal Variation Characteristics of Negative Air ion Concentration and Air Quality Evaluation in Songshan National Nature Reserve,Beijing

为研究北京松山自然保护区空气负离子浓度的时间变化特征,在植物生长季5–10月选取了3种典型林分和无林地对照组作为研究对象,用日本COM-3200PRO空气负离子检测仪对负离子浓度进行监测,并用安培空气离子评价指数对空气质量进行评价。结果表明:典型林分的空气负离子浓度日变化特征,除春季蒙锻(Tilia mongolica)林和黑桦(Betula dahurica)林外,夏季和秋季均呈“双峰型”曲线,全年生长季峰值均出现在9:00-11:00和16:00-17:00,谷值出现在13:00左右;月变化特征,除胡桃楸林(Juglans mandshurica)外均呈“单峰型”变化,林内外均表现为在7、8和9月负离子浓度较高;季节变化特征,林内外空气负离子浓度整体表现夏季(833±150 ion cm^(–3))>秋季(735±174 ion cm^(–3))>春季(632±178 ion cm^(–3));对空气质量进行评价表明,有林地的平均CI值为0.75±0.26,空气清洁,无林地的平均CI值为0.31±0.04,清洁程度在允许值范围内,表现为胡桃楸林(0.83±0.11)>蒙锻林(0.74±0.10)>黑桦林(0.67±0.13)>无林地(0.31±0.04)。

The aim of this study was to investigate the temporal characteristics of negative air ion concentration in the Songshan National Nature Reserve,Beijing.Hence,three typical forest stands and a nonforested land control group were selected during the growing season of May to October.The ion concentration was monitored using the Japanese COM-3200PRO negative air ion detector,and the air quality was evaluated using the amperometric air ion evaluation index method.The results showed that the diurnal variation of negative air ion concentration in the typical forest stands exhibited“double peak”curves,except for Betula dahurica forest in spring.The peak values of the annual growth season were attained between 9:00 and 11:00 as well as 16:00 and 17:00,and the trough value was attained at approximately 13:00.The monthly concentration variation characteristics in the stands showed“single peaks”,with the exception of the Juglans mandshurica forest.The negative air ion concentration was higher in July,August,and September both inside and outside the forest.The seasonal concentration variation characteristics showed that the negative air ion concentration inside and outside the forest followed the relation:summer(833±150 ion cm^(–3))>autumn(735±174 ion cm^(–3))>spring(632±178 ion cm^(–3)).From the air quality evaluation,the average CI value of the forested land was 0.75±0.26,indicating that the air was clean.The average CI value of the nonforested land was 0.31±0.04;the air quality was within an acceptable range.Overall,the concentration of each stand followed the relation:Juglans mandshurica(0.83±0.11)>Tilia mongolica(0.74±0.10)>Betula dahurica(0.67±0.13)>nonforested land(0.31±0.04).Varied forest stands have different temporal characteristics for negative air ion concentration and air quality.Using forest resources wisely,it is possible to significantly enhance the air quality in the Songshan National Nature Reserve.