关键词: 颗粒物, 质量浓度, 城市游憩林, 日变化, 无锡惠山

Abstract:

Urban forests can reduce atmospheric particulate matters, and hence improve the quality of ambient air. In this paper, the mass concentrations of TSP, PM₁₀, PM_2.5, and PM₁ in three typical recreational urban forests in the Hui Mountain of Wuxi were observed during the recreation time (5:00-19:00) in the summer of 2012 with a continued high temperature weather. In the same time, the microclimates were also collected to understand the dynamic pattern of particle matters mass concentration in the different types of urban forest, as well as the influencing factors. The results showed that: 1) The daily mean mass concentrations of particle matters in 3 recreation forests and road were lower than that of Wuxi urban region, and reached the urbanized area ambient air quality standards of China. The mass concentrations of TSP in Cinnamomum camphora forest and that of PM_2.5 in each recreation forest achieved the national standard level-Ⅰ. 2) The mass concentrations of different size particle matters varied in different recreation forests. The TSP or PM₁₀ concentration was lowest in C. camphora forest, and was highest in Quercus variabilis forest. The PM_2.5 or PM₁ concentration was lowest in Pinus elliotii forest, and was highest in C. camphora. The highest proportion of fine particles was PM₁₀, which accounted for more than 56%. 3) During the observation period, the concentrations of four kinds of particle matters in three recreation forests were high in the morning, and low in the afternoon, with the peaks usually appeared at 7:00, and the vales around 15:00. The time of concentration peaks or valleys of the different size particles varied. 4) The concentrations of four kinds of particles were significantly correlated with air moisture and temperature during the continued high temperature period. In addition, changes in the concentration of particulate matters were influenced by a variety of meteorological factors working together.

Key words: particle matter, mass concentration, urban recreational forest, diurnal change, Hui Mountain of Wuxi city