Green Roofs - Living Architecture Monitor - Winter 2012 - (Page 35)
BACK TO PLANNING’S ROOTS
lanning to protect the public’s health, safety and welfare began as a tool to address poor sanitation, overcrowded, dark urban tenements and poor working and living conditions. Many planners across North America believe it’s time to reconnect with our roots and more clearly align urban planning and public health issues. This approach is being pursued through programs which seek to make our towns and cities more amenable to pedestrians while concurrently addressing obesity though programs such as safe routes to school which encourage walking to school. Another aspect of this trend are programs to grow and deliver fresh fruit and produce in urban areas. I urge planners and public health officials to take a closer look at greening urban rooftops and walls as a means of achieving both public health and planning policy goals. Greening our urban rooftops and built up areas through the use of vegetated roofs and walls deploys a tool to address multiple public policy and public health goals. These include increasing public parks and open space in urban areas, providing a new location for urban agriculture,
storm water management (including reduction of combined sewer overflow), improved livability, improved air quality, and reduction of urban heat island effect. The connection between plants in urban areas and reduction of air pollution is pretty straight forward. At its most basic level plants absorb CO2 and produce oxygen. If we can reduce air pollution we will have cleaner air production reducing poor air quality events which concurrently reduces public health costs. Let’s look at the Urban Heat Island (UHI) effect. UHI results in increased incidence of smog throughout summer months with negative effects on air quality and respiratory health. Air quality is directly linked to the UHI effect through airborne pollutants such as NO2, NOx, SOx, CO2, CO and Particulate Matter (PM). Green roofs lower extreme summer temperatures with plants trapping particulate matter (especially PM10), and capturing gases, particularly carbon monoxide. A 10-20% increase in greened surface area on downtown buildings would contribute significantly to the social, economic, and environmental health of the municipality and its citizens (Currie, 2005).
Translating these public health benefits into dollars and cents has been addressed by Corrie Clark, Peter Adriaens and Brian Talbot in Green Roof Valuation: A Probabilistic Economic Analysis of Environmental Benefits published in Environmental Science and Technology 2008 and excerpted in the Living Architecture Monitor (LAM) spring 2008 article, The Big 3. Clark et al take a net present value approach to quantify the storm water, energy saving and public health benefits of installing a 2000 m2 green roof in Michigan. They use an EPA estimate health impact valuation between $1680 and $6380 per ton of NOx based on economic benefit from fewer premature deaths and fewer cases of chronic bronchitis. They used peer reviewed literature to establish the ability of green roofs to take up NOx at 0.27kg NO2/m2/y. This resulted in public health benefits for the 2000 m2 green roof on a one story building in Michigan ranging between $890 and $3390 per year. They note that results will vary based on different climates. They conclude that greening just 10% of Chicago roofs would result in city-wide public health benefits due to reduced air pollution of
$29.2 million to $111 million annually. For Detroit, 10% coverage would result in $24.2 million to $91.9 million annually – all thanks to cleaner air. Those are impressive numbers. It’s part of the planners’ role to bring this type of emerging information to the attention of decision makers. It moved me to recommend connecting public health and public policy goals to the Devens Enterprise Commission by adopting regulations which require 30% green roof coverage for any firm requiring an air quality permit that locates within the Devens Regional Enterprise Zone. By reconnecting public health with other public policy issues a stronger case is made for their adoption. By looking back to planning’s public health roots we can move our communities forward into the 21st century. Peter Lowitt, FAICP. Mr. Lowitt is Director of the Devens Enterprise Commission and former chair of Green Roofs for Healthy Cities. He also teaches a half day Green Roof Policy course for GRHC. Information on the DEC and its vegetative roof construction policies can be found at www.devensec.com/devserv.html
LIVING ARCHITECTURE MONITOR / WINTER 2012 / 35
Table of Contents for the Digital Edition of Green Roofs - Living Architecture Monitor - Winter 2012
Green Roofs - Living Architecture Monitor - Winter 2012
From the Founder
New Kid on the Green Roof
New Incentives for Green Roofs
On the Roof with Ben Flanner
Award Winning Green Roof and Wall Projects Represent!
Awards of Excellence Profiles
CitiesAlive 2012 – Building a Legacy of Outstanding Performance in Chicago!
Recognizing the Pioneer that was Malcolm Wells
Green roof and wall performance standards volunteers required!
Plant Profile: Thymus
Project Profile: Green Wall Maintenance Madness
GRP in Focus: Mary Ann Uhlmann
Project Profile: Healthy Haven for Community Members
A Positive Outlook for Urban Greening of Vacant Lots
A Green Space is a Clean Space
The Ambassador Program
New Corporate Members
GRHC Buyers Guide
Back to Planning’s Roots
Green Roofs - Living Architecture Monitor - Winter 2012