北京城市森林空气负离子与臭氧特征及相互作用

选取北京中心城区朝阳公园、近郊开发区南海子郊野公园、近郊浅山林区北京西山森林公园和远郊山地林区北京松山国家级自然保护区四个城市森林生态环境监测站长期定位监测的空气负离子和臭氧数据，分析其时空变化特征及相互作用。结果表明：时间变化上，夏季空气负离子和臭氧平均浓度均高于冬季，夏季和冬季空气负离子浓度日变化分别呈现“单峰单谷”和“单峰”曲线，2个季节臭氧浓度日变化均呈“单峰单谷”曲线；夏季空气负离子浓度分别在7：00—9：00出现峰值和15：00左右出现谷值，冬季空气负离子浓度峰值在12：00左右；夏季和冬季臭氧浓度谷值在7：00—9：00，冬季峰值在15：00，比夏季早2 h左右。空间变化上，城市污染梯度对空气负离子浓度空间变化影响不显著，夏季空气负离子浓度空间变化表现为市中心公园>远郊区公园>近郊浅山林区>近郊开发区，冬季也出现相同的规律变化；而臭氧浓度从市中心公园到远郊区公园逐渐下降，受城市污染梯度的影响大。夏季空气负离子浓度与臭氧浓度呈负相关关系，冬季空气负离子浓度与臭氧浓度呈正相关关系，说明植物生长会影响二者的相关性。

Characteristics and Interaction of Negative Air Ions and Ozone in Beijing Urban Forest

We select negative air ions and ozone data monitored for a long time by 4 urban forest ecological environment monitoring stations in Beijing, including Beijing Sun Park in the center, Nanhaizi country park which is suburban development zone, Beijing Xishan forest park which is suburban shallow mountain forest area and Beijing Songshan National Nature Reserve which is in the outer suburbs, to study and analyze their spatial and spatiotemporal variations and the interaction. The results show that the average NAI and O3 concentrations in Beijing urban forest were higher in summer than in winter, and the diurnal variation of air negative ion concentration in summer and winter presented 'single peak single valley' and 'single peak' curves respectively. The diurnal variation trend of O3 concentration in the 2 seasons shows a 'single peak single valley' curve; in summer, air negative ion concentration peaks at 7: 00–9: 00 and valleys at 15: 00, and peaks at 12: 00 in winter. The summer and winter O3 concentration valley value in 7: 00–9: 00, the winter peak at 15: 00, about 2 hours earlier than the summer. In terms of spatial changes, the urban pollution gradient has no significant influence on the spatial change of air negative ion concentration, the air negative ion concentration changes in summer are as follows: downtown park > outer suburb park > suburban shan-forest area > suburban development zone, the same pattern also appears in winter; the O3 concentration gradually decreases from the downtown park to the outer suburbs park, which is greatly affected by the gradient of urban pollution. NAI concentration was negatively correlated with O3 concentration in summer, and positively correlated with O3 concentration in winter, indicating that plant growth affects the correlation between the two.