北京西山国家森林公园中空气负离子浓度与气象因子的相关性研究

空气负离子(Negative air ions,NAI)是城市空气质量的重要指标之一,揭示城市森林释放NAI的影响机制,有助于充分利用NAI的净化作用及保健作用,并判断空气质量。利用北京西山国家森林公园2017年9月-2018年8月的NAI和气象数据,深入探究不同季节条件下和典型天气下影响空气负离子浓度(NAIC)的气象因素。结果显示,(1)不同季节条件下,NAI与气象因素相关关系不同。当温度在15℃以上时,NAIC与温度呈负相关;在15℃以下时,NAIC与温度呈正相关。多数情况下,NAIC与湿度呈反比,冬季湿度对NAIC负效应影响最明显(r=-0.503,P<0.01)。春秋冬NAIC与太阳辐射、气压均呈显著正相关关系,而夏季空气负离子与二者呈现负相关关系。(2)典型天气下,城市森林NAIC与晴天相比出现不同程度的差异,且与气象因子的相关性也不同。雨天条件下,NAIC日均值为2134ion·cm^-3,比晴天NAIC高4.56%,主要受温度和降雨量的共同影响;雾霾天与冬季晴天相比,晴天昼间NAIC为2075 ion·cm^-3,雾霾天昼间NAIC为1948 ion·cm^-3,主要受太阳辐射量的影响;大风天气下NAIC峰值比微风天气高5.37%,日均值大于微风天气,主要受气压的影响。

Correlation between Air Anion Concentration and Meteorological Factors in Beijing Xishan National Forest Park

With the constant improvement of living standard of residents in our country, demands of urban residents for city ecological environment, particularly air quality are increasing. Negative air ion(NAI) is one of the important indicators of urban air quality. Therefore, to reveal the mechanism of NAI release of urban forests can help further understand NAI, make full use of the purification effect of negative ions and health care effect, and determine the air quality. Using NAI and meteorological data of monitoring station at Xishan National Forest Park in Beijing from September 2017 to August 2018, this study explores the important meteorological factors influencing NAI concentration(NAIC) under different typical seasonal and weather conditions. The results show that:(1) The correlation between NAI and meteorological factors was different in different seasons. When the temperature was above 15 ℃, the NAIC was negatively correlated with the temperature. While when below 15 ℃, the NAIC was positively correlated with temperature. In most cases, NAIC was negatively correlated with humidity, with the strongest negative effect in winter(r=-0.503, P<0.01). The NAIC in spring, autumn and winter had significant positive correlation with solar radiation and air pressure, while the NAI in summer had a negative correlation with the above two factors.(2) In days with typical weather(rainy, haze, windy and breezy), NAIC in urban forest is different from that in sunny days, and its correlation with meteorological factors also performs differently. The daily average NAIC in rainy days was 2 134 ion·cm^-3, 4.56% higher than the NAIC in sunny days, which was mainly due to the combined effect of temperature and rainfall. In winter, there were 2 075 ion·cm^-3 in sunny days but only 1 948 ion·cm^-3 in haze days, which were mainly influenced by the solar radiation;NAIC peaks in windy weather were 5.37% higher than in breezy weather, and the daily average was also higher than in breezy weather, mainly due to pressure difference.