The AIRFRESH project to reduce air pollution from trees in the city for a better well-being of citizens

Mass urbanisation is one of the challenges of the 21st century, 82% of the population of the European Union will live in urban areas by 2030. The air pollution peaks and heat waves of summer 2019 in Europe, as well as the COVID-19 pandemic, have raised public awareness of the importance of wooded areas in cities for mitigating the effects of air pollution and climate change, as well as for the well-being of citizens. This awareness has initiated massive planting strategies as in Milan with a target of 3 million trees planted by 2030, or in the Southern region: target of 1 million trees planted by 2022. However, the planting of trees in cities must be the subject of prior expertise so that it is not counterproductive, particularly in terms of air quality.

The AIRFRESH project (2020-2025) is led by the Franco-Italian consortium composed of ARGANS, a company specializing in Earth observation, and Air Climat, which leads the GREC SUD in France, and two Italian public research institutions, ENEA (New Technologies, Energy and Sustainable Development) and l’IRET-CNR (Institute for Research on Ecosystems). The project is supported by the European LIFE programme. The city of Aix-en-Provence, the Aix-Marseille-Provence metropolitan area and the SUD region, together with the Nature For City LIFE project team, are stakeholders in the project.

Urban or peri-urban reforestation can help to improve air quality and meet air quality standards. To effectively reduce the levels of air pollutants in cities, municipalities and urban planners need a concrete, realistic and quantified assessment of the role of trees on air quality and an appropriate selection of tree species. Two pioneering cities have been selected as living laboratories : Aix-en-Provence (143,000 inhabitants) and Florence (380,000 inhabitants) whose populations are regularly exposed to pollution levels exceeding the protection limits set by the European Union and the World Health Organization.

In each city, a test area will be reforested (in 2022, equivalent to 1 ha). Campaigns to measure the concentrations of atmospheric pollutants and air temperature and humidity will be carried out before and after the trees are planted. The AIRFRESH project aims to :

- Measure and quantify the capacity of urban trees and shrubs to eliminate atmospheric pollutants.

- Estimate and quantify the environmental and public health benefits provided by the reforested area,

- Propose recommendations for planting policies (e.g. number and species of appropriate trees) for healthier air in the city, with the elaboration of a guide to feed urban policies for sustainable urban planning (Local Urban Plan, Urban Master Plan) and improve the well-being of citizens.

A communication will be set up for vulnerable people (e.g. elderly people, asthmatic children) with the creation of a table of "good practices" in doctors' waiting rooms to reduce the effects of air pollution on health. 100 trees will be planted by citizens and students. In the end, 1000 trees will be planted in the 2 cities.

Contact : Dr Pierre Sicard, ARGANS, France :

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