Why Cities Need Green Space More than Ever?

[This article has been published together with Diputació de Barcelona]

As a result of the COVID-19 pandemic and subsequent lockdown, we have seen an increase in stress, poor mental health, gender violence and calls for divorce. The confinement together with the economic downturn, resulting in many lay-offs, are some of the obvious causes.

Numerous studies have shown that the presence of greenness and visits to green space can reduce stress and improve restoration of the brain, and thereby improve mental health (Gascon et al 2015). Green space is essential for good physical and mental health.

Greening cities has many health benefits including longer life expectancy, fewer mental health problems and better cognitive functioning

During the lockdown in Catalonia, there was 90% reduction in green space visits as a result of the restrictions (Google 2020), reducing people's resilience

But unfortunately, in cities, we see often too little green space such as parks, forest or trees in roads. The World Health Organisation recommends that everyone has a green space of at least 0.5 hectares within 300 metres of their house (WHO 2016), but many people don’t, particularly in poorer areas.

Englischer Garten, Munich, Germany. (Ignacio Brosa / Unsplash)

Greening cities has many health benefits including longer life expectancy, fewer mental health problems, better cognitive functioning, better mood and healthier babies (Nieuwenhuijsen et al 2017). It also mitigates air pollution, heat and noise levels. It adds to CO₂ sequestration and therefore helps in our fight again the climate crisis. And green space can improve ecosystems and increase biodiversity in cities, particularly through well designed green infrastructure through the city (Coutts and Hahn 2015).

Replacing roads and car parking with green environments can be one way forward to change an environment from detrimental to beneficial for sustainability, liveable and health

A study showed that children who went to a school with more green space had a considerably better cognitive functioning than those who went to a school with less green space (Dadvand et al 2015), while another study found that early childhood exposure to green space leads to fewer mental health problems in adult life (Preuß et al 2019).

Multiple studies have found that green space reduces premature mortality, and increasing tree canopy from 20% to 30% in a city like Philadelphia could avoid more than 400 premature deaths annually (Kondo et al 2020). Particularly poorer neighbourhoods would benefit.

Click on the image for a better resolution.

Replacing roads and car parking with green environments can be one way forward to change an environment from detrimental to beneficial for sustainability, liveable and health (Nieuwenhuijsen 202). Before the COVID-19 pandemic, in a city like Barcelona, 60% of public space was taken up by infrastructure for the car (Ajuntament de Barcelona 2020). New urban models like the Barcelona Superblocks could increase green space and thereby improving health (Mueller et al 2020).

But it is not only green space that has many benefits, but also blue space like rivers, lakes and the sea, as they could provide space for restoration (Gascon et al 2017).

More than ever there is a need for more and larger outdoor natural public spaces [...] as they not only reduce the transmission risk of COVID-19 but also reduce stress and improve restoration

Some of the most effective measures to reduce the transmission of COVID-19 are physical distancing measures (1.5 metres distance), hygiene (e.g. hand washing) and being outdoors as the transmission risk of COVID-19 is very low compared to indoors. More than ever there is a need for more and larger outdoor natural public spaces such as parks, forests, road trees, rivers, lakes and seas, as they not only reduce the transmission risk of COVID-19 but also reduce stress and improve restoration. They are a great resource for people and society and an increased effort should be made to maintain and improve them to improve our mental health.

Aerial view of Barcelona. (Shai Pal / Unsplash)

References

• Ajuntament de Barcelona 2020 (Consultado el 12/05/2020)
• Coutts C and Hahn M. Green Infrastructure, Ecosystem Services, and Human Health. Int. J. Environ. Res. Public Health 2015, 12, 9768-9798
• Dadvand P, Nieuwenhuijsen MJ, Esnaola M, Forns J, Basagaña X, Alvarez-Pedrerol M, Rivas I, López-Vicente M, De Castro Pascual M, Su J, Jerrett M, Querol X, Sunyer J. Green spaces and cognitive development in primary schoolchildren. Proc Natl Acad Sci 2015;112(26):7937-42
• Gascon M, Triguero-Mas M, Martínez D, Dadvand P, Forns J, Plasència A, Nieuwenhuijsen MJ. Mental Health Benefits of Long-Term Exposure to Residential Green and Blue Spaces: A Systematic Review. Int J Environ Res Public Health. 2015;12:4354-4379
• Gascon M, Zijlema W, Vert C, White MP, Nieuwenhuijsen MJ. Outdoor blue spaces, human health and well-being: A systematic review of quantitative studies. Int J Hyg Environ Health. 2017; S1438-4639(17)30269-9.
• Google 2020 (Consultado el 21/05/2020)
• Kondo MC, Mueller N, Locke DH, Roman LA, Rojas-Rueda D, Schinasi LH, Gascon M, Nieuwenhuijsen MJ. Health impact assessment of Philadelphia's 2025 tree canopy cover goals. Lancet Planet Health. 2020 Apr;4(4):e149-e157.
• Mueller N, Rojas-Rueda D, Khreis H, Cirach M, Andrés D, Ballester J, Bartoll X, Daher C, Deluca A, Echave C, Milà C, Márquez S, Palou J, Pérez K, Tonne C, Stevenson M, Rueda S, Nieuwenhuijsen M. Changing the urban design of cities for health: The superblock model. Environ Int. 2020; 134:105132
• Nieuwenhuijsen MJ, Khreis H, Triguero-Mas M, Gascon M, Dadvand P. Fifty Shades of Green: Pathway to Healthy Urban Living. Epidemiology. 2017;28: 63–71
• Nieuwenhuijsen MJ. Urban and transport planning pathways to carbon neutral, liveable and healthy cities; A review of the current evidence. Environ Int. 2020 Apr 6:105661.
• Preuß M, Nieuwenhuijsen M, Marquez S, Cirach M, Dadvand P, Triguero-Mas M, Gidlow C, Grazuleviciene R, Kruize H, Zijlema W. Low Childhood Nature Exposure is Associated with Worse Mental Health in Adulthood. Int J Environ Res Public Health. 2019 May 22;16(10). pii: E1809.
• WHO. (2016). Urban green spaces and health. A review of evidence. Copenhaguen.

Other References

• Nieuwenhuijsen M 2020a
• Nieuwenhuijsen M 2020c