Effects of Urban Green Belts on the Air Temperature, Humidity and Air Quality

Abstract

As urbanization increases, designing green space that offers ecological benefits is an increasingly important goal of urban planning. As a linear green space in an urban environment, green belts lower air temperature, increase relative humidity, and improve air quality. To quantify the ecological effects of urban green belts and to identify a critical width for effective urban green belts, we analysed the width of urban green belts in terms of their effects on air temperature (T), relative humidity (RH), concentration of negative air ions (NAI) and bacteria rate (BR). The air T, RH and NAI from 8:00 to 18:00 and BR at 9:00 over seven days were investigated on six widths of green belts (0–10 m, 10–20 m, 20–30 m, 30–40 m, 40–50 m and over 50 m) along the west Fourth Ring Road of Beijing in April, July, October and December 2009. We found that (1) the T-RH benefits increased with the width of the green belts, and the 6 m belt had the smallest effect on T-RH, followed by the 16 m and 27 m belts, whereas the effect was obvious with the 34 m belt and conspicuous and stable with the 42 m belt (approximately 80% green coverage) (P < 0.05); (2) the critical width reference value of urban green belts for an obvious effect on the increase in NAI concentration was approximately 42 m (approximately 80% green coverage) (P < 0.05) and the NAI concentration increased with the width of green belts even in July; and (3) the positive effect on the decrease in the BR was greater than the negative effect, the BR decreased with the green belt width and the changes in the brs were stable with the 34 m belt. The results of this study may help urban planners and designers achieve urban green space designs that optimize ecological effects and cultural benefits.

Statistical Review of Quality Parameters of Blue-Green Infrastructure Elements Important in Mitigating the Effect of the Urban Heat Island in the Temperate Climate (C) Zone

“…Studies show that one large water body has a more significant impact on UHI mitigation than several smaller water bodies of regular shape with the same volume of water [ 134 ]. However, several smaller lakes affect a larger area of the city [ 135 , 139 ]. Hence, their effectiveness should be seen synergistically and qualitatively rather than in aggregate.…”

Changes in Habitat Suitability for Waterbirds of the Momoge Nature Reserve of China During 1990–2014

“…In recent years, many researches have done much work on environmental protection (Ilgürel et al 2016;Zhu et al 2017;Li, Zhao 2017), and the results from this study could give some perspectives on environmental protection through assessing the present status of habitat quality and monitoring the changes in habitat quality for waterbirds. Considering the changing impact on waterbirds habitat, the ecological planning, design and construction of nature reserves is needed to meet the environmental requirement.…”

Comparative Study of Urban Area Growth: Determining the Key Criteria of Inner Urban Development

“…Thus, to successfully manage the problem, urban growth boundaries that are given different names are used. Since the beginning of the 20th century, setting urban boundaries has been used as a tool for urban planning in a number of countries across the world [17]. Urban growth boundaries, or 'green bands', have been accepted as an urban development method that regulates urban growth by defining the area.…”