摘要：
[Objective] This paper was aimed to help tourists to select the best time to visit Beijing Fragrant Hills Park and to provide a theoretical basis for park greenbelt management and landscape setting.[Method] The measurements were continuously taken in 5 recreation points with different vegetation types in Fragrant Hills Park during a 10-day period in summer.The square outside the park was chosen as the control for comparisons.We analyzed the regularity of diurnal variation of every factor and statistically compared the difference and correlation of various ecological factors among the monitoring points,through analyzing micro climate changes,PM10 and PM2.5 mass concentration variation,differences of human comfort index,negative air ions concentration and noise pollution at the 6 monitoring sites.[Result] In the Fragrant Hills Park,daily temperature and relative air humidity showed single peak type curves.Relative air humidity increased by 6％,and air temperature decreased 1.7 °C on average.The longest duration with human comfort index reaching level Ⅱ were 8.5 hours.The PM10,PM2.5 mass concentration variation showed double peaks type curve,of which the values were high in morning and evening while low in afternoon.The average daily purification rates of every recreation points for PM2.5 reached 27.6％ and for PM10 reached 25.9％,respectively;Moreover,the two kinds of particles had significant positive correlation (P ＜ 0.01);The concentration variations of temperature and humidity variation showed significant negative correlation (P ＜ 0.05) and positive correlation (P ＜ 0.01);negative air ions concentration showed peak and valley alternately with changing regularity,3 peaks respectively occurred in the morning,noon and evening.Daily average index in the park was 795 ion · cm-3,2.43 times of the index outside the park,displaying significant negative correlation with PM10,PM2.5 concentration (P ＜ 0.01),significant negative correlation with temperature (P ＜ 0.05),and significant positive correlation with humidity (P ＜ 0.01).Each recreation point reached mild or moderate pollution levels at around 6:00 and 20:00-21:00,through the CI index analysis.Average index of noise in the park reached 40.3 dB and the average noise reduction rate reached 21.8％,showing significant negative correlation with plant canopy density (P ＜0.05).Meanwhile,plant canopy density showed significant positive correlation with negative air ions concentration (P ＜ 0.01) and negative correlation with PM10 and PM2.5 mass concentration (P ＜ 0.01).[Conclusion] We found that differences exist among various vegetation types in the Fragrant Hills Park in the ecological functions of increasing humidity,cooling temperature,antipollution,noise reduction etc.,the eco-environmental effect of Cotinus coggygria mixed forest was the highest while that of the grass lawn was the lowest,the reasonable recreation periods of Beijing Fragrant Hills Park in Summer were 7:00-11:00 and 17:00-20:00.%[目的]对香山公园典型植被生态环境效应相关影响因子分析评价,以期为游客选择香山公园最佳游览时间及公园绿地管理和景观设置提供理论依据.[方法]夏季连续10天在北京香山公园5处不同植物类型的游憩点进行测定,选择园外广场为对照,分析6处监测点微气候、PM10和PM2.5浓度、人体舒适度、空气负离子浓度及噪音情况,研究各因子日变化规律,并统计比较不同游憩点间差异和各生态因子间的相关性.[结果]香山公园日空气温度和空气相对湿度呈单峰型变化,平均降低空气温度1.7°C,增加空气相对湿度6％;人体舒适度达到Ⅱ级标准的时间最长可达8.5 h;PM10和PM2.5浓度均呈早晚高、午后低的双峰型变化特征,各游憩点对PM2.5日均净化率达27.6％,对PM10日均净化率达25.9％,2种颗粒物浓度间呈极显著正相关(P＜0.01),2种颗粒物浓度与温度、湿度分别呈显著负相关(P＜0.05)和极显著正相关(P＜0.01);负离子浓度呈波峰波谷交替变化,早、中、晚出现3个高峰,园内日均值为795个·cm-3,为园外的2.43倍,与PM10和PM2.5浓度极显著负相关(P＜0.01),与温度显著负相关(P＜0.05)、与湿度极显著正相关(P＜0.01),通过空气离子评价指数得出各游憩点均在6:00前后和20:00-21:00达到了轻度或中度污染;噪音呈现出早晚2个高峰,园内噪音平均值为40.3 dB,平均降噪率达21.8％,与植物郁闭度显著负相关(P＜0.05);植物郁闭度与负离子浓度极显著正相关(P＜0.01),与PM10和PM2.5质量浓度极显著负相关(P＜0.0l).[结论]香山公园绿地内不同植被类型间增湿、降温、抗污染、降噪等能力存在差别,黄栌混交林的生态效应最高,草坪最低;香山公园夏季合理的游憩时段为7:00-11:00和17:00-20:00.
