北京地区空气负离子浓度时空变化特征的研究

该文对北京地区空气负离子浓度的时空变化情况进行了为期3 a的实测与研究.结果表明，从市中心向郊区空气负离子浓度逐渐增大，单极系数逐渐减小；有林地区空气负离子浓度明显高于无林地区，针叶林地区全年平均空气负离子浓度高于阔叶林地区，但春、夏季节则阔叶林地区高于针叶林地区；有瀑布和溪流等动态水的地方空气负离子浓度明显增加；室内空气负离子浓度低于室外，但绿色植物可使室内空气负离子浓度增加；一天中白天空气负离子平均浓度高于夜间，一年中夏季最高、冬季最低. 

Spatio-temporal changes of negative air ion concentrations in Beijing

Mensurational and spatio-temporal changes of negative air ion concentrations in Beijing were studied between 1999 and 2002. The results showed that negative air ion concentrations increased gradually and ion polarity ratio decreased gradually from city center to suburb. The negative air ion concentrations in forested areas, were obviously higher than those in non forested areas; their annual average values in coniferous forests were higher than those in broad leaved forests but the opposite was true in spring and summer. The negative air ion concentrations obviously increased in the areas where moving water, such as waterfall and rivulet, exist. Indoor negative air ion concentrations were lower than outdoor ones but potted green plants could improve it. Over the span of a whole day it was higher during day time than during night time. Over a year its maximum appeared in summer and the minimum in winter.