关键词: 生态环境效应, 大气颗粒物, 人体舒适度, 负离子浓度, 噪音

Abstract: [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 PM_2.5 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℃ on average. The longest duration with human comfort index reaching level Ⅱ were 8.5 hours. The PM₁₀,PM_2.5 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 PM_2.5 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,PM_2.5 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 PM_2.5 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.

Key words: eco-environmental effect, atmospheric particles, human comfort index, negative air ions, noise