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The Benefits of Green and Blue Spaces in the Urban Environment

CONTEXT

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Reconnecting people with nature and promoting regular physical activity in green and blue spaces are two of the strategies that can best contribute to reducing the adverse effects that various aspects of the urban environment can have on health.

Well-managed green and blue urban spaces are ecologically, environmentally, socially and economically advantageous, but a good diagnosis of the city’s green infrastructure will generate further environmental benefits and also positively affect our physical and mental health.

Numerous recent studies show how the presence of green spaces in cities, when properly planned and managed, may have highly favourable effects for both the physical and the mental health of the population (Gascon et al. 2016). Similarly, contact with blue spaces (rivers, seas, lakes, fountains) has also been found to improve mental health and increase physical activity (Gascon et al. 2017). As a whole, natural spaces offer an ideal location for social interaction and contribute to the social cohesion of the neighbourhood, resulting in personal health benefits (Frumkin et al. 2017).

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In recent years, in-depth analyses have been conducted on the effects that the biodiversity of natural spaces may have on human health, that is, how the richness of natural heritage can positively affect people. In this sense, a wide range of scientific evidence indicates that a higher degree of biological diversity, normally associated with an increased presence of nature and the conservation of green and blue spaces, leads to an improvement in people's internal microbiota (the set of microorganisms that live in the human body) and in their immune systems (Gascon et al. 2015).

The soil of urban environments is remarkably heterogeneous and strongly conditioned by human activity. It has received increasingly more attention in recent years, posing a series of questions and challenges in relation to human health. Firstly, it is good to have a public space with large expanses of permeable soil with a good capacity for water retention and infiltration. These two factors propitiate savings in irrigation water and mitigate the effects of global change, especially in areas subject to flooding, which tend to channel and accumulate water when there is torrential rain. And secondly, the transpiration of the water from the soil contributes to improving the conditions of the microclimate (relative humidity, temperature) and has positive effects on our health. Although in some cases soil may accumulate pathogenic agents and toxic and radioactive products that cause a variety of intoxications and diseases (Steffan et al., 2017), it seems that research into the connections between urban soil and human health will be a growth area in the near future.

In short, the reasons why green (and blue) spaces contribute to improving our health are as follows:

  1. they increase physical activity
  2. they reduce stress and a sensation of recovery can be produced just by observing natural spaces
  3. they provide ecosystem services, given that plant life absorbs atmospheric contamination and offers shade and cooling thanks to the evapotranspiration of water, among other factors
  4. they generate a space where the community can carry out activities that contribute to greater social cohesion, a better quality of life and personal satisfaction,
  5. they foster biodiversity and stimulate the response of the immune system
    (Gascon et al., 2015; Rook, 2013; Sugiyama et al., 2008; WHO, 2016b; Wolf and Robbins, 2015).
 

OBJECTIVE

  • Improve the environmental quality of the city by establishing a network of green and blue spaces that are suitably planned and preserved.
  • Guarantee equal access to green and blue spaces for the entire population in order to foster the development of physical activity and social cohesion.

PROPOSALS AND RECOMMENDATIONS

  • Foster an increase in high-quality green and blue spaces. Guarantee fair distribution throughout the entire city so that every citizen can reap the benefits of these spaces.
  • Actively favour the presence of spaces with the highest possible degree of natural elements, given that this increases the diversity of species and the beneficial effects to people’s health.
  • Implement measures for the management of green and blue spaces to favour the diversity of habitats and species, minimising, for example, the use of pesticides, using indigenous species and natural materials, and fostering the maximum naturalisation of the spaces, wherever possible.
  • Increase the surface area of permeable soil in order to favour the infiltration of water in the case of torrential rain and to regulate the microclimate.
  • Foster the natural regeneration of unoccupied spaces, facilitating their naturalisation with low-intensity, low-impact and low-cost measures to favour the recovery of habitats and species.
  • Connect green and blue spaces to peri-urban natural spaces and the region's entire natural heritage, creating what is known as green infrastructure. To this effect, it is necessary to ensure continuity between the spaces and foster green and blue corridors, which, moreover, bring nature closer to the public and encourage physical activity.
  • Ensure, as per the WHO’s recommendations, that there is an urban green space of at least half a hectare at a linear distance of no more than 300 m from every citizen.
  • Ensure that the parks are equipped with infrastructure (benches, public toilets, fountains, adequate signage, lighting, visible accessibility, bins, etc.) to allow people to walk, cycle and exercise, given that it is associated with a greater degree of intensity and enjoyment of physical activity (Gladwell et al. 2013).
  • Ensure, wherever viable, that the majority of streets have plant life (at least ten trees per block) to create healthier routes with shade and improve the aesthetics of the built environment (Kardan et al. 2015).
  • Plant the most suitable species in accordance with the width of the pavements and the buildings. The species to be chosen should preferably contribute to an increase in biodiversity, be indigenous, generate very little pollen and be deciduous, allowing sunlight to shine through into houses in winter and generating shade in summer (Cariñanos & Casares-Porcel 2011).
  • Increase air purity through plant life (e.g. increase plant cover by planting shrubs under the crowns of the trees). Trees are an efficient means of reducing numerous contaminants.
  • In areas with high levels of surface air pollution (e.g. on urban streets), plant cover should be located along the street without fully covering it. This allows the contaminants to disperse from a high level and increases purification by the adjacent trees.
  • Plant life can be used to attenuate noise. The tree cover in this case should be high density, the trunks of the trees should be thick and the greater the distance between the streets, the vehicles and the pedestrians, the better (Van Renterghem, 2014).
  • Ensure the presence of green and blue spaces in densely-structured urban zones that are susceptible to suffering the effects of urban heat islands. These spaces help reduce the ambient temperature in urban areas (e.g. the evapotranspirational property of the plant life increases humidity and the trees generate shade).
  • Consider green facades and roofs to improve the energy and thermal efficiency of buildings.

REFERENCE EXPERIENCES

Information only available in Catalan

 

 

 

LEGISLATION

  • There is no specific legislation. However, the European Commission has approved various communications in relation to green infrastructure (see references section).
  • WHO recommendations (guarantee the presence of a green space of at least half a hectare at a linear distance of 300 m from every point).

STUDIES AND TECHNICAL DOCUMENTATION


Scientific papers:

  • Basagaña, X. et al. 2011. Heat waves and cause-specific mortality at all ages. Epidemiology, 22(6); 765-772.
  • Cariñanos, P., Casares-Porcel, M., 2011. Urban green zones and related pollen allergy: A review. Some guidelines for designing spaces with low allergy impact. Landscape and Urban Planning, 101(3).
  • Frumkin, H., et al., 2017. Nature contact and human health: A research agenda. Environmental Health Perspectives, 125(7), 1-18.
  • Gascon, M. et al., 2015. Mental Health Benefits of Long-Term Exposure to Residential Green and Blue Spaces: A Systematic Review. International Journal of Environmental Research and Public Health, 12(4).
  • Gascon, M. et al., 2016. Residential green spaces and mortality: a systematic review. Environment International, 86.
  • Gascon, M. et al., 2017. Outdoor blue spaces, human health and well-being: A systematic review of quantitative studies. International Journal of Hygiene and Environmental Health, 220(8).
  • Gladwell, V. et al., 2013. The great outdoors: how a green exercise environment can benefit all. Extreme Physiology & Medicine, 2(3), 1-7.
  • Hamra, G., et al., 2015. Lung cancer and exposure to nitrogen dioxide and traffic: A systematic review and meta-analysis. Environmental Health Perspectives, 123(11), 1107-1112.
  • Héroux, M., et al., 2015. Quantifying the health impacts of ambient air pollutants: recommendations of a WHO/Europe project. International Journal of Public Health, 60(5), 619-627.
  • Kardan, O. et al. 2015. Neighborhood greenspace and health in a large urban center. Scientific Reports, 5(11610), 1-14.
  • OMS, 2016. Urban green spaces and health: A review of evidence, Copenhagen.
  • Pugh, T., et al., 2012. Effectiveness of green infrastructure for improvement of air quality in urban street canyons. Environmental Science and Technology, 46(14), 7692-7699. 
  • Santamouris, M. et al., 2015. On the impact of urban heat island and global warming on the power demand and electricity consumption of buildings - A review. Energy and Buildings, 98, 119-124.
  • Steffan, J.J.; Brevik, EC; Burgess, L.C.; Cerdà, A. (2018) The effect of soil on human health: an overview. Eur J Soil Sci. 2018 Jan;69(1):159-171.
  • Vert, C., et al. 2017. Effect of long-term exposure to air pollution on anxiety and depression in adults: A cross-sectional study. International Journal of Hygiene and Environmental Health, 220(6), 1074-1080.

OTHER LISTINGS OF THE GUIDE

  • Fitxa  "Impactes sobre la biodiversitat i el patrimoni natural".

More information about addressing the Public Health Service: entornurbasalut@diba.cat

Date of last update:
dg., 09 de maig 2021 07:40:03 +0000