Like many urban areas globally, Amsterdam faces the increasing challenge of urban air pollution. This empirical study, conducted within the AMS Urban Comfort Lab, investigates the direct impact of green walls and vertical greenery on urban air quality. Distinguishing from previous research relying on simulations and models, our early study results reveal a significant 18% reduction in pollutant levels associated with integrating green walls. Using machine learning, we identify green walls locations in Amsterdam and quantify their potential in delivering cleaner air. As Amsterdam and cities worldwide grapple with declining air quality, this research offers a glimpse of a future where urban environments prioritize environmental sustainability and public health.

The sustainable use and management of water resources for metropoles are becoming more challenging due to climate change, population growth, and land use change by urbanisation. For the metropole region Amsterdam, these impacts are evidenced by increased saltwater intrusion as well as more drought periods. Urban Greenery (UG) is seen as an indispensable infrastructural component for a liveable environment, as it offers a variety of socio-economic and environmental benefits like heat stress reduction, recreational opportunities, as well as rainwater buffer zones (Gemeente, 2020; Hansen, 2018; Jabbar et al., 2022; Stobbelaar et al., 2022). It is of great importance to sustain UG with adequate water resources, and hence emerged as an important policy agenda for cities like Amsterdam. The concept of Rainwater Harvesting (RWH) is seen as an interesting approach to sustain UG and its multi-functionalities, and subsequently alleviate (fresh)water scarcity at city scale (Jha et al., 2014; McCarton et al., 2021). Besides, integrating RWH measures as Nature-based Solutions (NbS) could provide additional co-benefits1. This research focuses on the development of a Planning Support System, which enables the long-term, climate adaptive planning of RWH measures to provide an alternative water source to sustain UG. The decision-support tool has the purpose to 1. Identify priority water demand areas and 2. Provide advise on suitable (Nature-based) RWH measures for the storage of rainwater. In order to plan rainwater reuse for sustaining Urban Green in the long term, a new conceptual framework was needed. This innovative framework links climate dynamics, RWH storage measures, and water demand of UG. The framework is applicable at city scale and overcomes long term planning by accounting for climate scenarios for a specific outlook year. The first goal focuses on distinguishing the species-specific water demand of UG and identify the temporal water balance for specific climate scenarios. The second goal focuses on providing advise on suitable RWH locations by identifying the spatial/physical characteristics of the area and assessing a selection of RWH measures on their performances. Altogether, the tool provides an overview on which (Nature-based) RWH measures can to what extent provide rainwater in periods of drought in a certain scenario. The framework and planning support system will be validated and operationalized by applying them on defined case areas within Amsterdam and generate an overview for decision-makers on what interventions can be made regarding sustaining urban green and increasing climate resilience within the city.

Urban vegetation – encompassing all trees, shrubs, lawns, and other vegetation in cities –, if adequately managed, can play an important role to ensure a good quality of life and meet the challenges set by Agenda 2030, helping to reach 15 Sustainable Development Goals: indeed, in urban environments it can provide several ecosystem services, such as air purification, global climate regulation, temperature regulation, run-off mitigation as well as recreational opportunities, increasing aesthetic values. In a few words, urban vegetation can help make cities safer, healthier, wealthier and more attractive, with benefits grouped in social, communal, environmental and economic categories. This key role is now being threatened by climate change impacts and extreme weather conditions, that limit urban vegetation lifespan and so its ability to provide ecosystem services. Among other cities worldwide, a clear example of this can be seen in Milan, Italy. Indeed, last July, the city has been hit by a tremendous storm - strong winds over 100 km/h, more the 40 mm of rains in just 10 minutes - causing huge damages and losses to the city, including the urban vegetation (high percentage of trees down). We have been called to quantify and assess this vegetation loss, and propose compensation actions. In doing that, we proposed and are now applying a new methodology to first screen the damages, and then to quantify the environmental loss. The methodology encompasses two layers: a field one, to collect punctual data (e.g., species and dimension of the damaged trees) and a analytic one, leveraging on European Space Agency images, to evaluate the difference before and after the storm in terms of tree coverage, with a resolution of 50 cm. This procedure helped to clarify most hit areas within the city, counting the tons of Carbon no more stored in the trees and other lost ecosystem services, and it has been useful now to properly plan new urban forests around the city, setting clear and verifiable goals in term of tree cover, helping the city to recover. Therefore, from a negative event and incredible loss, thanks to this innovative approach, Milan is now ready to reshape its urban greenery and to become more sustainable than before. The same methodology can be applied to new neighborhood or building projects, to keep track of urban greenery changes and benefits.