Unequal Green Space - Candice Powers
Countries around the world are witnessing increasing urbanization as people are pulled towards cities with the promise of more job opportunities and greater prosperity. Half of the global population currently resides in an urban setting and it is projected that two-thirds of people will live in urban areas by 2050. However, city living inherently reduces one’s access to nature and green spaces. The location and quality of these natural spaces are associated with numerous demographic factors, including the socioeconomic status (SES) and racial or ethnic background of surrounding inhabitants. Disproportionate access to green spaces is not only a matter of environmental justice, but also a pressing public health concern as natural spaces provide an array of mental and physical benefits. In our continuously urbanizing world, it is essential that we identify which populations are in greatest need of gaining access to green spaces and that we understand the abundance of health benefits they can confer to their visitors.
Two of the greatest problems facing the world today are poverty and environmental degradation. These two issues converge in our nation's cities and threaten human health, especially in the face of global climate change. For instance, concentrated energy use in cities leads to greater air pollution, with urban regions consuming 67%-76% of global energy and producing almost 75% of global carbon emissions. Green cover is a resource that usually moderates temperature and helps to curb the detrimental effects of urban heat islands. Individuals living within a heat island are more likely to experience heat stress as urban areas are 5-11°C warmer than surrounding rural landscapes. However, urban impediments to root growth, such as underground infrastructure, chemical contamination, and extensive cement, prevent the expansion of such beneficial urban tree cover.
As compared to buildings and concrete sidewalks, canopy cover has a greater capacity to reflect solar radiation, which can lower heat mortality by 40-99%. We can help increase urban tree growth by planting trees in previously designated green spaces and transforming vacant, cement-dominated urban spaces into plots where plant species can thrive. A greater presence of carbon-capturing photosynthesizers can support a cleaner atmosphere while protecting against the hazards posed by extreme temperatures
Along with their critical environmental benefits and ecosystem services, green spaces are important communal features for fostering better mental, social and physical health in human populations. The National Recreation and Parks Association, as well as the Trust for Public Land and the Congress for New Urbanism, advocate for having parks located within 400 meters of all urban residents. Notably, there is evidence that access to urban park resources is often stratified by class and ethno-racial dimensions. Information regarding which areas are most deprived of quality natural spaces is crucial when approaching urban planning and development, processes that have implications for the health of surrounding communities.
The evolution of property development in the United States is inherently intertwined with histories of ethno-racial oppression. Consequently, green spaces are often unequally distributed between white communities and those composed of racial minorities. A widespread review by Wolch et al. found that people of color are typically located where green space is scarce or of poor quality. An on-site survey of 911 visitors to Chicago’s Lincoln park found that 80% of white users came from neighborhoods adjacent to the park while only 60% of minority users came from these same areas of close proximity. Additionally, while 42% of white respondents reported visiting the park “virtually every day,” only one-third of black users identified themselves as “heavy users'' who visit over 25 times per year.
The various factors that determine green space accessibility were further investigated in Atlanta, Georgia, a city where only 15% of census-recorded citizens are within 400 meters of green spaces. The study examined the location of 890 green spaces within 564 census tracts in the ten core counties of the Atlanta Metropolitan Statistical Area and used “estimated travel time along road networks to green spaces” to determine the accessibility in each census tract. The neighborhoods that had significantly poorer access to these natural spaces had higher percentages of black citizens, more households with more than one occupant per room, more carless households, and more populations below the poverty line than communities with easy access. Although both socioeconomic status and race factor into this phenomenon, the study found that green space disparities were stronger among different races than among different SES, with African Americans experiencing a clear deprivation of access to natural spaces.
These disparities in accessibility can translate into differential mental well-being. A study conducted in the United Kingdom quantified green space in English urban settings and subsequently collected personal mental health data from 12,818 individuals who responded to a short-form, 12-item General Health Questionnaire. They found that individuals living in urban areas with more access to green space had lower mental distress and higher overall well-being than those with less access to green space.
A study conducted in Wisconsin analyzed the relationship between green space exposure and mental health across both rural and urban environments. Data from the 2008-2011 cohorts of the Survey of the Health of Wisconsin displayed that better mental health outcomes were associated with higher levels of neighborhood green space. This correlation held true even when controlling for a multitude of individual and neighborhood confounding factors. They found higher levels of depression, anxiety, and stress in areas with less than 10% tree canopy cover. Specifically, for every 25% increase in tree canopy cover, the Depression Anxiety Stress Scale (DASS) score decreased by one point.
There are a host of other studies that bolster the claim that nature, outdoor access, and surrounding greenness are associated with increased general mental health and well-being. In Perth, Western Australia, Wood et al. investigated the mental health of 565 residents. They found that for every additional park added to a neighborhood, the Warwick-Edinburch Mental Well-Being Scale (WEMWBS) scores of neighbors increased by 0.11. Overall, the number of parks and total park area were positively associated with mental well-being. Finally, Tang et al. found that, as compared to urban landscapes, simply viewing natural environments can have a positive effect on mental health.
More specifically, attention restoration theory predicts that experiences in natural environments have the ability to reduce mental fatigue, thereby restoring the capability for directed attention. This is because interactions with nature can facilitate fascination attention: an involuntary state that does not require as much effort as directed attention. It is important that we seek out increased engagement with our fascination attention as our modern, fast-paced, urban environments are not always conducive to this variety of thought. In the context of Tang’s study, observing water or mountain environments relaxed the attention system by reducing activation of the visual brain area, improving mental elasticity and well-being.
Mental health is of elevated concern in children and adolescent populations as they are still in the process of developing essential attributes. The CDC reported in 2016 that one in every seven children in the US between the ages of 2-8 suffered from a mental, behavioral, or developmental disorder. Examples include ADHD, depression, anxiety, and learning delays. This same report found that half of adolescents in the US have a mental disorder, and ¼ have a severe impediment as a result of the disorder. Children of today's generation are also spending less time in nature and more time in front of screens watching TV and playing video games. With these phenomena in mind, researchers have investigated the possible connection between time spent in green space and mental disorders in children.
Amoly et al. explored the impact of green space contact on behavioral development and symptoms of ADHD in schoolchildren aged 7-10 in Barcelona. The children’s parents responded to questions about time spent playing in green spaces,sociodemographic factors, and household characteristics, along with completing a Strengths and Difficulties Questionnaires regarding their child’s behavior. Additionally, teachers rated the ADHD symptom criteria of each student. They found that high quality and quantity green space was associated with fewer total difficulties, emotional symptoms, and peer relationship problems. Kuo and Taylor also conducted a study looking at the impacts of green spaces on symptoms of ADHD, but in children between 5-18 across the United States. Again, parents were asked to rate the child’s symptoms of ADHD, but this time specifically in relation to the aftereffects of common after-school and weekend activities. For these kids, activities in green outdoor settings reduced inattention and hyperactivity.
Beyond these apparent behavioral advantages, exposure to green space has been shown to benefit cognitive development and performance on standardized tests. A study conducted on 3rd grade students across elementary schools in Massachusetts found that surrounding greenness in March–the month when most schools administer the standardized exam– was associated with achievement in English and Math, as measured by the Massachusetts Comprehensive Assessment System. Wu et al. also found that higher exposure to greenness for the balance of the year yielded better academic performance. The researchers adjusted for income levels, gender, and levels of urbanization, yet still found a significant association between the Normalized Difference Vegetation Index (NDVI) and performance.
In addition to bolstering mental health, green spaces foster the development of physical wellness. This issue of physical activity is pertinent as less than half of US adults meet daily exercise recommendations. Significantly, a review of 38 studies reported strong evidence for the ability of park-based and greenway intervention to promote physical activity. Another review of over 143 studies supports this conclusion that exposure to green space is associated with better physical health since heart rate, risk of type II diabetes, and all-cause mortality all decreased with increased green space access. When summed over an entire population, the health gains can become substantial.
Notably, the impression of neighborhood safety is critically important for realizing the positive effects of green space. In Weimann’s study of 28,198 participants, the greenness score of communities was positively associated with physical activity, but only in the group that perceived their neighborhood as safe. Despite the breadth of benefits that can be provided by expanding the quality and quantity of green spaces, efforts to confer these advantages will go unrewarded if planners don’t incorporate the holistic concerns and needs of the citizens they’re trying to help.
Beyond the initial barrier of outcompeting housing, transport, and other uses for vacant urban areas, urban green spaces must be strategically planned in order to avoid gentrification and benefit the communities that need them most. For instance, a survey of 250,782 Dutch adults revealed that those in lower income brackets and without private health insurance suffer from greater anxiety, stress, and depression. Therefore, making green spaces accessible to these groups would be of great service.
When incorporating more natural space into a community, the area will intrinsically become more attractive and desirable. In turn, housing costs are likely to go up and displace current inhabitants who were part of the population that the intervention was targeting. Since this process of “green gentrification” can have negative social and public health implications, it is essential to develop strategies to implement changes that are “just green enough” to promote greater welfare while upholding the original community. This means listening to various community concerns and desires when formulating projects as well as prioritizing the underprivileged who would be helped the most. Further, interventions that are of smaller scale or in scattered locations are less likely to foment rounds of gentrification as there will not be one focal point for property development. This approach is supported by the finding that an increase in the number of small, district, and regional parks were all positively associated with high WEMWBS. With local, small-scale alterations, residents are more likely to be exposed to the benefits of having nature in close proximity.
Overall, research supports urban green space interventions for the promotion of environmental and human health and well-being. The pathways through which green spaces are thought to improve mental health include: (1) the facilitation of physical activity, which promotes positive mood and reduces stress, (2) providing locations for planned and coincidental social interactions which improve mental well-being, and (3) supplying a site to relax and recuperate from stressful activities. Notably, the burden on healthcare facilities could potentially be reduced through the increased development of green spaces that promote better physical and mental health. Through identifying underserved areas and populations, mainly urban poor minority residents, it is easier to decide where efforts to enhance access to green space should be focused.
The results of studies investigating the distribution and benefits of green spaces provide key considerations for public policy making, urban planning, and efforts to mitigate health and wellness inequalities. Along with larger-scale interventions, low-cost, ‘soft measures’ such as signage and promotional events have shown to effectively engage communities in using green space. In relation to childhood health, greater quality and quantity of green space should be promoted as a means to diminish the symptoms of certain behavioral disorders, such as ADHD, and increase academic performance. Finally, the enhanced ability of water environments, as compared to other natural landscapes, to decrease respiratory rates and increase mental restoration indicates that planners should attempt to include water features in green spaces if possible. In conclusion, there are very few, if any, public health interventions that are able to achieve such sweeping enhancements of environmental and human well-being as equitable urban greening.
Recommended Reading
Dahmann, N., Wolch, J., Joassart-Marcelli, P., Reynolds, K., & Jerrett, M. (2010). The active
city? Disparities in provision of urban public recreation resources. Health & place, 16(3), 431-445.
Dai, D. (2011). Racial/ethnic and socioeconomic disparities in urban green space accessibility:
Where to intervene? Landscape and Urban Planning, 102(4), 234–244. https://doi.org/10.1016/j.landurbplan.2011.05.002
McCormick, R. (2017). Does Access to Green Space Impact the Mental Well-being of Children:
A Systematic Review. Journal of Pediatric Nursing, 37, 3–7. https://doi.org/10.1016/j.pedn.2017.08.027
Sister, C., Wolch, J., & Wilson, J. (2009). Got green? addressing environmental justice in park provision. GeoJournal, 75(3), 229–248. https://doi.org/10.1007/s10708-009-9303-8
Twohig-Bennett, C., & Jones, A. (2018). The health benefits of the great outdoors: A systematic
review and meta-analysis of greenspace exposure and health outcomes. Environmental research, 166, 628-637.
Wolch, J. R., Byrne, J., & Newell, J. P. (2014). Urban green space, public health, and
environmental justice: The challenge of making cities ‘just green enough.’ Landscape
and Urban Planning, 125, 234–244. https://doi.org/10.1016/j.landurbplan.2014.01.017
About the Author
Candice is a senior in the College majoring in Environmental Biology and minoring in Women’s and Gender Studies. She is passionate about marine conservation, environmental justice, and the intersections of gender and sustainability. Her upbringing in coastal Maine has fostered her dedication to protecting our natural spaces and commitment to ensuring equitable access to the great outdoors. In her free time, Candice enjoys hiking, sea kayaking, walking her dog Ted, and watching NPR Tiny Desk.