Urban Built Environment, Cities, and Traffic: Sources of Heat-Island Effects, Increasing Energy Demand and Air Pollution, Causing Public Health Hazrad, and Degrading Quality of Life.
The heat-island effect is often observed in cities where green, wooded, and open spaces have been replaced by a jungle of built surfaces of asphalt roads, concrete structures, and buildings. Contrary to what is commonly thought, this effect is present in both large and small cities. As the following tweet indicates even NASA claims to understand the impact of heat-island effect and is studying big cities (New York and Los Angeles examples) and expending research money to mitigate these effects where damage is clearly visible.
Research at the University of Mississippi: My current research and previous graduate research work of Dr. Kanok Boriboonsomsin in the mid 2000’s has demonstrated that the heat- island effect is present even in the small rural town of Oxford, Mississippi. Mitigation efforts should not be focused on cool roof surfaces only but growing more trees and building parks/lakes. These efforts would be much will be more effective in reducing heat-island effects. The addition of these green spaces and encouraging citizens to grow their own plants and vegetables will help increase the likelihood that the general public will join in heat-island mitigation and promote a more sustainable healthy life style.
The White House Initiative: Some months ago First Lady Michelle Obama invited families to participate in planting and gardening activities on the White House grounds. I wish this great enthusiasm and initiative of the First Lady to promote sustainability practices in our own backyard would become a national campaign. Unfortunately to my knowledge, this initiative was not followed by EPA, department of education, and other federal and state agencies, non-profit organizations, public leaders, and media.
Example from Arid Region: In the small arid country of the United Arab Emirates (UAE) one city “Dubai” chose to follow the example of vertical growth of large U.S. cities. This resulted in very high density growth and poor air quality due to the lack of attention paid to increased traffic congestion and the reduction of open green areas. This observation is shown in photos on the left taken when I visited UAE in August 2004. On the other hand, the green city “Abu Dhabi” was developed just 120 km away where the former ruler’s love of greenery and biodiversity led to sustainable urban development with lots of green spaces.
Adverse Impacts of Heat-island Effect: Key points follow from my presentation on the subject made at the 2009 Annual Meeting of the Transportation Research Board of the National Academies.
- Carbon emission data of the U.S. from 2003 is 15% above 1990 levels.
- Both in 1990 and 2003, California, Texas, Florida, New York, and Pennsylvania had with the highest emissions.
- These states had large urban areas and a larger share of vehicle-miles driven.
- Warming of 2.2 °C (4 °F) could increase ground-level ozone (O3) concentrations by about 5%.
- EPA estimated (June 15, 2004) that 126 nonattainment areas for the 8-hour ozone criterion included 474 counties which were home to 159 million people.
- Increased demand of energy by large urban areas causes more carbon emissions and consequently more adverse impacts on greenhouse gas (GHG) emissions.
- Increased ambient temperature in a city causes extra usage of electricity and an increased demand on power consumption.
- Increased emissions from power plants cause increases in air pollution and GHG emissions.
- Mortality and morbidity rates due to urban air pollution are significant and cause substantial societal costs related to public health problems and lost productivity.
USAID/National Academies Project Example of a Coastal Megacity: My graduate students used geospatial analysis of submeter resolution satellite imagery to create a comprehensive road and landuse map of southern Karachi. The Karachi part area landuse map was mapped for surface temperatures using my temperature prediction model. This type of surface temperature map is a vital indication of heat-island severity and extent.
Example of Madrid, Spain: In my previous post about the 2012 European Green City Award given to a Spanish city, a video link shows how Madrid has converted concrete and asphalt roads to a park by moving a segment of city traffic corridor underground. This is a great example of reducing built up area’s heat-island and traffic impacts and enhancing biodiversity and quality of life. http://infrastructureglobal.com/?p=2589
Dr. Uddin’s note: I discussed the impacts of area and transportation sources on greenhouse gas and other air pollution in prior posts. I discuss these topics in detail in my Chapter 23 on “Mobile and Area Sources of GHG” published in Climate Change Mitigation Handbook, Springer, 2011.