Air quality improvement

Fondo Unido Chihuahua, in collaboration with its corporate partners, is committed to raising awareness about environmental care and reforestation. One of its flagship initiatives is the annual tree-planting campaign, "Planting Today to Have Oxygen Tomorrow," organized by United Way Chihuahua in Ciudad Juárez. This environmental initiative focuses on improving the quality of different urban green spaces (parks, school grounds, streets) while fostering ecological awareness in vulnerable communities across the city. The primary objective is to plant a significant number of trees throughout Ciudad Juárez, using native species that are water-efficient and well-adapted to the local climate and soil. In 2022 the initiative aimed to reforest 18 parks located mainly in the south-eastern part of this border city with 1,000 trees. In 2023 and 2024 the intervention focused on planting 850 trees scatted all over the city.

The campaign brings together donations and volunteers through partnerships with various stakeholders, including local and regional governments, private companies, community organizations, and the general public.
United Way Chihuahua oversees the planning, coordination, and logistical efforts for the campaign. On planting days, volunteers gather at designated sites, guided by the organization to ensure successful planting efforts and community engagement (Ref 1-4).

The Miraflores Bicentennial Park has been built on the Malecón de la Reserva and the Quebrada de Armendáriz. It was inaugurated in June 2022 as one of the created projects within the framework of the commemorations of the 200 years of Independence celebrations (1). It is considered a new green lung of Lima (2), as it has a green area of 30,400 square metres and stands on one of the cliffs of the Costa Verde (1). It has a system of terraces that replicates the construction model of the Incas, which has made it possible to additionally reinforce the soil and the slopes with the use of retaining walls up to 10 metres high, with horizontal geogrids and vertical geocells (1, 2). It was structured on a stabilised slope in order to mitigate the risk of landslides (4), and an irrigation system was implemented to stabilise the soil (4).
This space was built as a biodiversity garden with more than 160,000 xerophilic coastal species with low water consumption, 300 trees and 80 palm trees. It also offers places for tourism, such as viewpoints and squares, where cultural events, open-air activities and rest areas are held (1). It also aims to connect aspects of landscape conservation, preservation of biodiversity in the city, and the construction of a cultural landscape in which human action is complementary and friendly to the natural environment (9). Finally, it seeks to contribute to the reduction of the municipality's carbon footprint by reducing the harmful effects of urban expansion on the Lima cliff ecosystem, such as deforestation, water pollution and loss of biodiversity (9).

For a Forest in Your Neighborhood" is an afforestation campaign by the DDOR insurance group, launched in 2022 as part of their Environment, Society, and Governance (ESG) commitments (Ref. 1). Site selection was based on online votings, with thousands of votes being casted from 188 towns across Serbia (Ref. 2). In the end, the fifteen most popular cities were selected for project implementation. As a result, hundreds of trees were planted, including 25 trees along the promenade of Belgrade’s Ušće Park in 2023 (Ref. 3). Ultimately, the initiative aims to create and enhance urban green spaces, to improve air quality and living conditions in Serbian cities (Ref. 5). The success of the campaign encouraged DDOR to extend the campaign in 2024, financed through their eco-insurance schemes (Ref. 4)

Due to rapid urbanization and development, cities in China, including Kunming, face challenges in managing neglected urban spaces, particularly vacated demolition sites and leftover land (Ref 1, 2, 3). To address this issue and enhance residents' well-being, Kunming has created 400 pocket parks since 2022, transforming forgotten corners into vibrant green spaces (Ref 4, 5).
One of these parks, Wenxing Pocket Park in Xishan District, was built in 2023 on 2.3 hectares of land (Ref 6). Located next to a secondary school and two protected historical relics, the park not only preserves historical heritage but also reflects cultural value (Ref 6, 7). In addition to increasing urban green spaces, the park provides recreational and physical facilities for residents, children, and students (Ref 6). Its design is inspired by traditional architectural styles and incorporates wood craftsmanship, as well as ecological sponge facilities (Ref 6, 7).
The park also features science gardens, promoting awareness and knowledge of herbs and sustainability (Ref 6). The project employs methods such as infiltration, stagnation, storage, purification, and drainage to manage rainwater effectively. By utilizing the natural terrain, it creates ecological dry streams and sunken gardens that absorb and store rainwater, helping to control runoff. This approach aligns with the "sponge city" concept, promoting natural water accumulation, infiltration, and purification.
Additionally, the integration of various plants enhances the microclimate, supporting local wildlife and creating a healthy, vibrant public space. The Wenxing Pocket Park has been implemented by the Municipality of Xishan. (Ref.6,7)

Liquid 3 is the first urban photo-bioreactor in Serbia, developed by an interdisciplinary team at the Institute for Multidisciplinary Research at the University of Belgrade (Ref. 1,2,3). Prompted by an appeal of the United Nations Development Programme (UNDP), the team was eager to find novel approaches to combat the city's severe air pollution issues while being space efficient and providing year-round benefits (Ref. 3). The key to the bioreactor are algae which are very efficient in sequestering carbon and filtering heavy metals from the air (Ref. 2). A Liquid 3 feature can be quickly set and occupies a plot of only 3 m². Some of its benefits include its ability to withstand high levels of air pollution and its ease of installation on surfaces like walkways and other sealed infrastructure (Ref. 2,3). Additionally, by design, Liquid 3 integrates amenities such as power outlets, a bench, and nighttime lighting (Ref. 1). The selected strain of algae can tolerate temperatures between 5-35°C making it deployable all year. However, monthly maintenance is required, during which the water and algae are replaced—both of which can be repurposed, for example, as fertilizers (Ref. 6).The project has received global media coverage as well as a prize for the best innovative and climate-smart solution in Serbia. Its success has prompted the installation of two more such bioreactors in Serbia, with interest coming from other countries such as Hungary and the UAE (Ref. 1,4).

In the city of Ciudad Juárez, the municipality, in collaboration with UN-Habitat, aims to design and create a park that encompasses the yards and unmaintained areas surrounding the railway station, transforming these spaces into an accessible and safe public area. This project covers over 500,000 square meters and addresses not only degraded areas but also several public squares. Described as "a coordinated urban recycling strategy," this initiative seeks to repurpose existing public squares and rehabilitate neglected spaces into vibrant green areas that feature universal accessibility, native vegetation, and urban furniture designed to enhance safety. The project also aims to provide increased recreational opportunities, improve permeability, and introduce additional shaded areas. A key component of improving permeability involves the restoration and incorporation of acequias—traditional historical irrigation systems that absorb and manage excess rainwater, thereby reducing the likelihood of flash floods.
Additionally, the project focuses on the restoration and promotion of significant historical buildings, such as the old railway station and the whiskey factory, integrating them into a larger cultural and sports facility area at the municipal scale. The overarching goal is to revitalize the site through effective coordination with the relevant authorities responsible for the spaces adjacent to the railway station, stretching from Plaza Misión de Guadalupe to Blvd. Municipio Libre. This collaborative effort aims to accommodate both sports and cultural facilities while also creating a green corridor.
Furthermore, the project intends to reforest, redesign, and enhance Plaza Misión de Guadalupe, Plaza Monumento a Benito Juárez, and other residual public spaces and gardens. This initiative aligns with its Public Space Strategy, which emphasizes the development of gender-inclusive and resilient public spaces.(Ref 1, 3, 4).

The Silk District is a real estate project by Prime Kapital in partnership with MAS P.L.C., integrating green spaces into its urban design (1-10). It focuses on regenerating a brownfield site, an abandoned industrial area left undeveloped in one of Iasi's neighborhoods (1). The project aims to revitalize the area, improving its aesthetics, reducing pollution, and repurposing it into a commercial and residential space (1). A key feature of the project is the incorporation of green spaces throughout its design (1).
The development spans 101,000 square meters, with 40,500 square meters (combined) dedicated to green spaces and "car-free" open areas (1, 2, 6, p.2). These green elements are designed to offer spaces for relaxation, recreation, and social interaction, while also contributing to environmental benefits such as air filtration, temperature regulation, rainwater drainage, and soil erosion prevention, all promoting better health for residents (1, 2, 4, 6, p.12). The landscape design includes “green islands” and vegetation-covered roofs for parking structures (4).
Launched in 2021 after receiving municipal approval, the project is ongoing and has already made significant progress, with over 10,000 perennial plants and 401 trees planted (4, 9). Upon completion, the landscape will feature 7,100 square meters of perennials, 3,000 square meters of shrubs, and an urban forest containing 2,400 trees (6, p.12).
The total investment in the project is €20,000,000 (7). In 2024, one of the completed office buildings earned a BREEAM green certification, achieving one of the highest possible scores, in collaboration with the consulting firm BuildGreen (5, 8). The landscape design was carried out by the architectural firm Beros Abdul+ (4). Before receiving approval, the project was opened for public consultation, and an independent online survey showed strong support from the community (15, 16).

Tempelhofer Feld stands as an innovative green solution in the heart of Berlin, addressing several issues of environmental justice, biodiversity, and urban resilience. Within the S-Bahn ring, only one in 20 residents lives in areas well-served by green spaces, and districts like Neukölln, Kreuzberg, and Tempelhof would face even greater scarcity without this vast expanse. Many residents in these neighborhoods lack access to private green spaces such as gardens or balconies. Without nearby parks, people are compelled to travel to other districts, exacerbating the congestion of green spaces and increasing local traffic.
Since its opening in 2010, Tempelhofer Feld has provided Berlin with over 300 hectares of open, green, leisure, and recreational space, making it one of the largest urban open spaces globally. Once the site of bustling air traffic, it is now a sanctuary for activities such as skating, strolling, gardening, picnicking, birdwatching, kiteboarding, and more. These wide-ranging uses showcase its transformation into an accessible, multifunctional green space that serves as a social equalizer, particularly for disadvantaged neighborhoods, a significance amplified during the Covid-19 pandemic.
The field is not just a recreational haven but also a vital ecological refuge. With over two-thirds of its area designated as green space, it hosts diverse ecosystems, including extensive natural meadows, lawns, and protected habitats for birds and other species. Certain areas are closed to the public to preserve these sensitive environments, emphasizing the balance between human activity and ecological conservation. Since 2019, animal landscape keepers, including around 100 resident sheep, have contributed to sustainable land management practices, promoting biodiversity and ecological health (Ref. 2).
Managed collaboratively by political, administrative, and societal actors, the site exemplifies integrated citizen participation in urban planning. (Ref. 3)

The World Health Organization estimates that 80% of the population in developing countries use medicinal plants for health prevention and care, primarily in rural areas (3). These plant species have therapeutic potential in treating various diseases, and they are considered safe and effective medications with fewer side effects and affordable prices (3). In Peru, medicinal plants have historically been used to treat respiratory, gastrointestinal, and digestive ailments. To this day, they continue to be used by both native and urban communities (3).
To promote, develop, and encourage research, innovation, and technologies related to the use, preservation, conservation, and employment of medicinal and food plants, the National Center for Social and Intercultural Research in Health (CENSI) of the National Institute of Health (INS) has inaugurated its medicinal and food plant nursery located in one of its facilities (Chorrillos) in Lima (1, 3). The primary objective of this project is to adapt various species from the coast, mountains, and jungle of the country and initiate a plant production program that contributes to improving public health, environmental quality and the revitalization of the ancestral knowledge of indigenous, Amazonian, Andean, and Afro-Peruvian communities (1). Additionally, it aims to contribute to mitigating the effects of climate change by creating green areas, reducing atmospheric carbon dioxide levels through plant photosynthesis, improving soil quality, and promoting the responsible use of water resources, among others (3).
For the development of this project, the INS is working in collaboration with the International Organization for Migration to benefit not only the health and well-being of the Peruvian community but also promote the integration and care of the migrant population in the country (2).

In Lisbon's Areeiro district, Urbem, a non-profit organization, is leading the creation of a 2500m2 Miyawaki mini-forest in Casal Vistoso Urban Park. This initiative involves densely planting native species to rapidly establish a diverse, self-sustaining forest ecosystem. Supported by the Lisbon City Council, the project aims to enhance urban biodiversity, improve air quality, and contribute to climate resilience. Volunteers from the local community play a crucial role in every stage, from preparing the land to planting and maintaining the forest. Despite initial challenges, such as a 40-50% plant survival rate, the forest is expected to become self-sustaining within three years. The project focuses on environmental restoration and seeks to engage and educate the community, fostering a sense of ownership and connection to these new green spaces (Ref 1; Ref 2; Ref 3; Ref 4).