Does urban greenery improve our health?

Can the fact that you live on a tree-lined street or that you are within a few minutes' walk from a park impact your physical and mental health? This question has drawn a lot of interest in recent years, especially with the concerns of climate change, pollution and overpopulation, and it is undeniable that more and more research points to strong connections between urban greenery and public health.

One study of note by the University of Exeter Medical School, published in the journal Environmental Science & Technology, found that parks and greenery do have a big impact on the mental health of nearby residents. They examined 1,000 participants who had either moved to a greener urban area or to one with less greenery and found, according to lead author Ian Alcock, "that individuals who move to greener areas have significant and long-lasting improvements in mental health."

Urban greenery's impact on memory and mood was the subject of a study at the University of Michigan where they found that students who walked through an urban arboretum were found to score higher than those students who walked on city streets.

Many other studies also have been coming to the similar conclusion that we need to pay more attention to the importance of greenery in our urban landscapes. A review of academic studies by Danish researchers for the International Federation of Parks and Recreation Administration found that: "The direct health benefits for which we found evidence on positive effects included psychological wellbeing, reduced obesity, reduced stress, self-perceived health, reduced headache, better mental health…reduced cardiovascular symptoms and reduced mortality from respiratory disorders."

Green living in Philly

Here in Philadelphia, a team at Drexel University is doing its own work on the impact of urban greenery on health.

A new team of faculty from the School of Public Health and Westphal College of Media Arts & Design is looking at the connections between urban design and natural systems with public health through several community-based projects in West Philadelphia. In December, Drexel's Urban Design and Health Team was selected as one of 11 inaugural members of the American Institute of Architects (AIA)'s Design & Health Research Consortium which will provide them support and resources through workshops and discussion forums.

The Drexel researchers' central hypothesis is that aspects of natural systems can be woven into existing urban systems to create healthier populations through design. They will be placing special focus on the Mantua neighborhood.

On why they chose Mantua as the focus of their projects, Dr. Yvonne Michael, an associate professor in the School of Public Health, one of the principal investigators of the new team, said, "They are our neighbors here at Drexel and the neighborhood has relatively high levels of poverty, poor health and other disadvantages."

The projects will include a clean, sustainable and safe playground to be built at the Morton McMichael Elementary School in Mantua beginning in summer 2015, three community gardening initiatives, and a walking program at the Mantua Presbyterian Apartments, a low-income senior housing complex, where Drexel students have already designed and built an urban garden. Lap markers will be placed in the garden to help the residents get their steps in.

The team hopes to generate data that is useful to city residents and policy makers in understanding and addressing the causes of urban health problems and health inequalities.

Dr. Michael herself has been studying for years the effect the natural environment has on our health.

"There is growing evidence linking the natural environment to human health," she said. "It has been shown to affect our cardiovascular, respiratory, mental and overall self-reported health."

"In 'Physical Activity Resources and Changes in Walking in a Cohort of Older Men', a study for the Osteoporotic Fractures in Men Study Group, we looked at people's access to parks and trails, specifically community-dwelling older men (65 and older)," she reported.

The research team of which she was a member tracked the older men's physical activity levels over a two year period and found that those who lived closer to parks and trails were more likely to maintain or improve their physical activity compared to men living further away.

According to Dr. Michael, urban greenery can also affect birth outcomes. In "Urban trees and the risk of poor birth outcomes," she was a member of a group that investigated in Portland, Oregon whether greater tree-canopy cover is associated with reduced risk of poor birth outcomes like low birth weight and restricted growth of the baby. They found that a 10% increase in tree-canopy cover within 50m of a house reduced the number of small for gestational age births by 1.42 per 1000 births.

She was also involved in a national study, "The Relationship between Trees and Human Health: Evidence from the Spread of the Emerald Ash Borer," that used the Emerald Ash Borer, a parasitic beetle lethal to Ash trees, to measure how trees affect cardiovascular health. This particular beetle is known to decimate Ash trees which are the most common trees in urban areas so researchers looked at areas infested with the beetle and found that the lack of trees did seem to be linked to an uptick of lower-respiratory tract disease (LRTD) and cardiovascular disease (CVD) mortality rates. According to the report, "the borer – a marker for tree loss - was associated with an additional 6113 deaths related to illness of the lower respiratory system, and 15,080 cardiovascular-related deaths."

This increasing evidence of the need for more green spaces within the city has highlighted the importance of the design of built environments here in Philadelphia.

Teaching informed design

Debra Ruben, an associate professor and director of interior design programs in the Westphal College of Media Arts & Design said, "Design and public health has always had a strong connection and the consortium is a perfect way to foster this type of collaboration underscoring the important role that the built environment plays in the health and well-being of the community."

Ruben as part of the Urban Design and Health Team is working on the McMichael School playground project. D.S. Nicholas, an assistant professor in the department of Architecture & Interiors in the Westphal College is working on the Presbyterian Gardens

"As an AIA member myself, this is a good fit. I have already been thinking a lot about informed design," Nicholas said. "Being user-focused, current trends in design are looking at how research can help inform design."

Ruben added, "As a designer, I haven't been trained on getting quantitative measurements so this collaboration with Public Health is very important to me. It is a way to document the impact our design has on people's behavior."

She explained further that at the school playground at McMichael they will be measuring the physical and social activities on the blacktop currently there now and repeating these measurements after the playground is built to see if there is an improvement.

"Our projects will not only help us understand how built environments impact our users' health, but their behaviors as well," Nicholas added.

Community involvement will be a big part of these projects according to Dr. Michael. "Poor neighborhoods have fewer resources. We want to empower the community to help them be involved with identifying problems and finding solutions, and perpetuate a cycle of positivity."