The benefits that urban open spaces provide to
citizens can be categorized into four basic forms:
recreation,
ecology,
aesthetic value, and positive health impacts.
Psychological research shows that benefits to visitors of urban green spaces increased with their
biodiversity, indicating that "green" alone is not sufficient: the quality and variety of the urban green space are important as well.
Recreational park in
Bratislava (Slovakia) Urban open space is often held in esteem for the recreational opportunities it provides. Examples of recreation in urban open spaces include active recreation (such as organized sports and individual exercise) and passive recreation. Research shows that when open spaces are attractive and accessible, people are more likely to engage in physical activity. Time spent in an urban open space for recreation offers a reprieve from the urban environment and a break from
over-stimulation. Studies on physically active adults, middle-aged and older, show that there are amplified benefits when physical activities are coupled with green space environments. Such coupling leads to
decreased levels of stress, lowers the risk of
depression, and increases the frequency of participation in exercise.
Ecological in
Providence, Rhode Island. Green spaces may improve the air quality of urban areas and provide habitat for wildlife, improving the overall ecological health of urban environments. They may also reduce the risk of
flooding by providing
rainwater
drainage.
Aesthetic Urban spaces also hold a certain
aesthetic value. People enjoy viewing nature, especially when it is otherwise scarce, as is the case in urban environments. Therefore, open space offers the value of "substituting gray infrastructure." One researcher notes how attractive
neighborhoods contribute to positive attitudes and social norms that encourage walking and community values. Properties near urban open spaces tend to have a higher value. One study was able to demonstrate that "a pleasant view can lead to a considerable increase in house price, particularly if the house overlooks water (8–10%) or open space (6–12%)." Certain benefits may be derived from exposure to virtual versions of the natural environment, too. For example, people who were shown pictures of scenic, natural environments had increased brain activity in the region associated with recalling happy memories, compared to people that were shown pictures of urban landscapes.
Impact on health in
Kollam city,
India, is the largest open space available in any of the city limits in
Kerala state. The
World Health Organization considers urban green spaces as important to human mental and physical health. Urban open spaces often include trees or other shrubbery that contribute to moderating temperatures and decreasing
air pollution. Perceived general health is higher in populations with a higher percentage of green space in their environments. Urban open space access has also been directly related to reductions in the prevalence and severity of chronic diseases resulting from sedentary lifestyles, improvements in mental well-being, reduction in gun violence, and reductions in population-wide health impacts from
climate change.
Mechanism of urban open space health effects Access to urban open space encourages physical activity and reduces ambient air pollution, heat,
traffic noise, and
emissions. Urban open space has also been attributed to providing cleaner air quality, thus reducing rates of chronic respiratory diseases among the surrounding population. Urban open space can provide venues for outdoor physical activity which can increase lung function and be a protective factor against respiratory disease. These spaces also offer exposure to nature, which has been proven to boost the
immune system by introducing microorganisms to the human body through contact with
soil,
turf, or
forest floor.
Reductions in chronic disease rates Improved access to green space is associated with reductions in
cardiovascular disease symptoms, improved rates of
physical activity, lower incidence of
obesity, and improved
respiratory health. Lower rates of cardiovascular
biomarkers are associated with access to green space, showing a reduction in cardiovascular disease risk in populations living within 1 km of green space. Not only does access to urban green space reduce risk of cardiovascular disease, but increased access has been shown to improve recovery from major adverse cardiovascular events and lower all-cause mortality. Relationships have been found between increased access to green space, improved rates of physical activity, and reduced BMI.
Reductions in mental illness rates and improvement of social cohesion Globally,
mental illness is linked to eight million deaths each year. In
urban areas, limited access to green space and poor quality of green spaces available may contribute to poor mental health outcomes; according to some studies, people living in
cities and
towns may have weaker
mental health in comparison to people living in less crowded areas. Urban green spaces are pieces of nature in the cities designed to address this problem. The distance an individual lives from a green space or park and the proportion of land designated as open space/parks have been shown to be inversely related to the number of anxiety/
mood disorder treatments in the community. Improved mental health may therefore be related to both measures—to distance from open space and proportion of open space within a neighborhood. Even when physical activity rates do not increase with greater access to green space, greater access to green space decreases stress and improves social cohesion.
Effects on respiratory health Adequate urban green space access can be associated with better respiratory health outcomes, as long as green space areas meet certain requirements. A study showed that mortality due to
pneumonia and chronic lower
respiratory diseases could be reduced by minimizing fragmentation of green spaces and increasing the largest patch percentage of green space. Vegetation type (
trees,
shrubs and
herbaceous layers) and lack of management (
pruning,
irrigation and fertilization) has been shown to affect a higher capacity to provide the
ecosystem services of
air purification and
climate regulation within green urban spaces. The types of plants and shrubs are important because areas with large tree canopies can contribute to asthma and allergic sensitization.
Impacts on high temperatures in
Singapore Urban areas tend to have higher
temperatures than their surrounding undeveloped areas because of urban heat islands (UHIs). Urban heat islands are areas with man-made infrastructure that contribute to increased temperatures. The average temperature during the day in cities can be 18–27 degrees Fahrenheit higher than in the surrounding rural regions. Shading comes from the taller plants, such as trees, that can contribute to lowering the surface heat island effect. The shade provides protection from the sun for vulnerable populations, such as children, during periods of increased temperature, during the summer months, or during a heat wave. Tree cover prevents some solar radiation from reaching the ground with its leaves and branches. and convert CO2 into oxygen through photosynthesis. In urban green spaces, trees filter out man-made pollutants.
Air quality data collected on cities with and without urban green space has shown that areas with an abundance of trees have considerably less air pollutants, e.g.
O3, PM10,
NO2, SO2, and CO. As air pollutants accumulate in the atmosphere, vulnerable populations, such as children, may suffer from increased incidences of respiratory disease. Globally, particulate matter has increased over 28% in indoor air and 35% in outdoor air. Children spend most of their time at school, around 10 hours daily, and the indoor and outdoor air has a large impact on their health. Schools located in urban areas have higher particulate matter than schools in rural areas. Compared with children in schools located in rural areas, children who attend schools located in industrial areas and urban cities have higher levels of urinary PAHs (
polycyclic aromatic hydrocarbons) metabolites, which is linked to air pollution. Green spaces can reduce the pollution of particulate matter by preventing distribution of particulates from pollutants or by reducing the particulate matter from traveling to other places. Higher exposure to tree canopy and pollen was associated with a higher prevalence of rhinitis, allergic sensitization, wheezing, and asthma among children 7 years-old. The access to green spaces has shown an association with recreational walking, increased physical activity, and reduced sedentary time in all ages.
Impacts on mental health Children exposed to urban green spaces have the opportunity to expend energy by interacting with their environment and other people through exercise. One study has shown that without access to urban green spaces, some children have problems with hyperactivity, peer interactions, and good conduct. Interactions with nature, animals, and peers have positive influences on child development and reduction in burnout and distress related to having ADHD
Attention Deficit Hyperactivity Disorder (ADHD). Urban green space can also improve mental health by providing children access to a community. Recreational activities and playing at the park gives children opportunities to interact with other children and develop a social circle and set of social skills. A 2021 study found that higher exposure to woodland urban green spaces, or
urban forest, but not grassland spaces, is associated with improved cognitive development and reduced risks of mental problems for
urban adolescents. ==History==