September 1, 2023

Urban health equity is a priority for the UHC, particularly as evidence mounts that climate change will have a greater toll in disadvantaged neighborhoods. A growing body of research points to greenspace in cities having an equigenic effect – that is, the ability to promote health equity through the neighborhood environment. According to this theory, adding certain amenities to neighborhoods, such as parks and tree cover, could have more significant effects on the health of disadvantaged residents than on residents with more advantages. For example, having access to a park could allow people who can’t afford a gym membership more opportunities to increase physical activity – as well as opportunities to relax and socialize, which can be just as beneficial to health.

A recent study led by UHC Affiliate Leah Schinasi, PhD, MSPH explores how greenspace in Philadelphia can modify prevalent socioeconomic and racial/ethnic inequities in all-cause and cardiovascular disease mortality. Does Urban Greenspace Reduce Mortality Inequalities Based on Poverty, Race, or Both in Philadelphia, PA?, recently published in the Journal of Urban Health, used a range of measures of greenspace, including an area’s overall greenness, the proportions of tree canopy, grass and shrub cover, and residents’ self-reported access to or comfort using local greenspace. 

“In our paper, we investigated the hypothesis that urban green space availability is associated with weaker inequities in all-cause and cardiovascular disease mortality rates, across Philadelphia census tracts,” Dr. Schinasi tells us. “Our results support the hypothesis that urban green space may reduce racialized or poverty-based inequities in mortality.”

Their findings underscore the potential of greenspace to ease inequities in urban mortality rates. As the article’s authors remind us, racism in U.S. cities can affect people’s access to greenspace. “The most substantial reductions were in association with inequities that may be rooted in historical and present-day systems of marginalization, such as racialized residential segregation," Dr. Schinasi explains. Historically redlined and redlined racially segregated neighborhoods often have fewer trees – an observation borne out by Dr. Schinasi and team, who found that greenspace measures were higher in wealthier, whiter areas of Philadelphia. Additionally, the expectation of personally-mediated racism can prevent people from visiting these spaces. 

Here in Philadelphia, a number of a number of studies by UHC researchers have shown the health-protective effects of greenspace in our communities:

• Living in an area with more tree canopy cover can reduce income-based differences in self-reported mental health conditions – an effect that was shown to be especially valuable during the height of the COVID-19 pandemic, when visiting greenspace was shown to protect Philadelphians’ mental and physical health.
• Perceived access to greenspace and tree canopy cover can be protective against cardiovascular disease.
• The proportion of greenspace in a neighborhood could be a factor in infant mortality rates, as infant mortality was 27% higher in less green compared to more green tracts.

Philadelphia’s Office of Sustainability’s Greenworks Plan includes a program to increase tree canopy coverage to 30% in every neighborhood. A health impact assessment co-authored by Dr. Schinasi and published in Lancet Global Health found that this policy could prevent about 400 premature adult deaths in Philadelphia every year, with the most benefit seen in neighborhoods with lower socioeconomic status.

“Results from our work contribute to a mounting body of evidence suggesting the importance of green interventions for health and health equity promotion. Our results may be useful to stakeholders who are interested in promoting greening policies and programs in Philadelphia, or in other similar urban settings.”

However, cities must take care when developing plans to green neighborhoods. Adding greenspace to under-resouced neighborhoods can result in gentrification, which can ultimately cause residents to feel excluded from these spaces or even priced out of their neighborhoods. As the study authors note, “Increasingly, cities are using greenspace interventions to promote health and equity; understanding the types of greenspace that provide the greatest benefits is critical.”

Dr. Schinasi's co-authors included UHC researchers Janelle Edwards, MPH, Jane E Clougherty, MSc, ScD, Anneclaire De Roos, PhD, MPH, and Usama Bilal, PhD, MPH, MD. 

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