Effect of ecosystem services provided by urban green infrastructure on indoor environment: A literature review

The influence of urban green infrastructure on the indoor environment and the effects on human comfort and economic consequences are still unclear. This paper gives a systematic overview of the relationship, in terms of so-called 'ecosystem services', between urban green infrastructure and the indoor environment through a literature review in different disciplines. Urban green infrastructure (mainly trees, green walls and roofs) was found to contribute, both positively and negatively, to the indoor environment via the influence on the climate, energy use, air quality, sonic environment and aesthetic quality. Four main factors that influence these effects were identified, being vegetation characteristics, building characteristics (including layout and geometry), and geographical conditions. Although the reviewed papers have investigated the different ecosystem services on a wide range of space and time scales, the performance of urban green on the meso-and macro climate has received less attention than on the micro scale. Also direct effects of urban green infrastructure on indoor air quality and sonic environment were rarely studied. Another finding is that, whereas the modelling approach on climate regulation has been widely adopted by researchers throughout the world, empirical studies have mainly been performed in the USA. We also analysed the data found on economic implications. The economic effects of adjoining vegetation and green roofs on climate regulation provided energy savings of up to almost $250/tree/year, while the air quality regulation was valued between $0.12 and $0.6/m(2) tree cover/year. Maximum monetary values attributed to noise regulation and aesthetic appreciation of urban green were $20 - $25/person/year, respectively. Of course these values are extremely time-and context-dependent but do give an indication of the potential economic effects of investing in urban green infrastructure. Based on this review, we conclude that new methods, measurement instruments and field experiments are needed to improve empirically supported correlations and develop concrete recommendations for urban planning and design. (C) 2014 Elsevier Ltd. All rights reserved.