How do Travel Demand and Economics Affect the Development of Urban Road Networks?

A Model of the Rise and Fall of Roads (33 page pdf,  Zhang, LeiLevinson, David M, Systems Symposium at the Massachusetts Institute of Technology, Mar. 2004)

Today we review a seminal paper from over a decade ago that examines the dynamics of road development in a major mid-West American city (Minneapolis-Saint Paul) using a model that combines measures such as travel demand statistics (usually found on Origin Destination studies) with the economics of road pricing or tolls, geographical constraints (such as rivers and mountains) and how these change with newer technology over time (in this case over 20 years). Roads represent both figuratively and physically the link that join the issues addressed in this blog: how traffic is linked to pollution and how pollution is linked to health. Of particular interest is the way that travel demand and road volume capacity (VC) interact with road tolls and the cost of road construction and the resulting revenue that may be used to ease congestion, in addition to the overall design of the road network and design for a major urban area.

road-links

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The Tire and Brake Share of Traffic-Related Air Pollution

Air pollution: Tyre and brake fatigue compound an exhausting problem (OECD, Shayne MacLachlan, OECD Environment Directorate, Sep.8, 2016)

Today we review research into the impact of particles generated from tires and brake wear. The amount of particulate matter for an average urban arterial road with 25K vehicles per day can produce up to 9 kg of dust per km- bigger roads or highways with 100K VPD can produce four times that. Recycled tires from the billion cars in the road globally into materials used in playgrounds is being called the new asbestos. Banning petrol powered cars from cities to encourage e-cars and cycling means less emissions from the tailpipe and good for carbon emission reduction but it also means the same wear and particles from brakes and tires, in terms of air pollution and health, even from bicycles!

Studded tyre Español: Neumático de invierno co...

Studded tyre Español: Neumático de invierno con clavos, modelo Nokian Hakkapeliitta 4 (Photo credit: Wikipedia)

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How Can Cities Reduce Methane Emissions?

Mitigation of methane emissions in cities: how new measurements and partnerships can contribute to emissions reduction strategies (39 page pdf, Francesca M. Hopkins, James R. Ehleringer, Susan E. Bush, Riley M. Duren, Charles E.Miller, Chun-Ta Lai, Ying-Kuang Hsu, Valerie Carranza, James T. Randerson, Earth’s Future, Sep. 10, 2016)

Today we review research into methane emissions from cities which along with other greenhouse gases contributes to climate warming. Cities themselves account for 70% of GHG emissions globally.  Unlike CO2 however, methane emissions are more easily managed at the city level whether they come from transportation and the increased shift to natural gas as a fuel for city vehicles or, secondarily, from landfills where methane is emitted from decomposing organic materials or, thirdly, from leaks in the systems delivering natural gas to users. One of the major problems is the lack of accurate inventories of methane emissions which in some cities results in an underestimate of 50%. Some efforts being made in the transportation sector to reduce CO2 emissions include shifts to the use of propane or natural gas but these may have unintended consequences in terms of their contribution as a radiatively active gas to the greenhouse effect. Landfill emissions may be reduced by simply reducing the amount of waste generated though pricing of garbage or encouraging home composting.

methane-emissions

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The Future of the World and Cities in It

Urban futures: anticipating a world of cities (6 page pdf, Geci Karuri-Sebina, Karel-Herman Haegeman and Apiwat Ratanawaraha, Foresight, Sep. 10, 2016)

Today we review an introduction to a series of papers on cities from a foresight point of view. It begins with a prediction that the city has evolved from the city-state in Ancient Greece to city-worlds in the next 100 years. By 2050, 70% of the world’s population will live in urban areas, compared to 54% today. While cities can improve economic prosperity, reducing poverty and becoming more inclusive socially, there are also downside risks of unemployment and poverty, as well as tensions based on religion, race and values – in addition to the major health threats that resulting congestion and emissions from downtown traffic where city government has not taken steps to alleviate. While cities are good at generating problems they also have a problem solving capability. The paper ends on an optimistic note: “In a world that increasingly appears ungovernable, cities – not states – are the islands of governance on which the future world order will be built”- something that those who try to come to grips with climate change and urban air pollution need to acknowledge and take count of in reducing carbon emissions and adapting to the challenge.

Indoor and Built Environment

Indoor and Built Environment (Photo credit: Wikipedia)

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How is Air Pollution Linked to Type 2 Diabetes?

Association Between Long-Term Exposure to Air Pollution and Biomarkers Related to Insulin Resistance, Subclinical Inflammation and Adipokines (Abstract, Kathrin Wolf, Anita Popp, Alexandra Schneider, Susanne Breitner, Regina Hampel, Wolfgang Rathmann, Christian Herder, Michael Roden, Wolfgang Koenig, Christa Meisinger, Annette Peters, KORA-Study Group, Diabetes, Aug. 8, 2016)

Also discussed here: Air pollution a risk factor for diabetes, say researchers (ScienceDaily, Sep.8,  2016)

And here: Diabetes Research – Risk Factor Air Pollution (Press Release, Helmholtz Zentrum München, Sep. 8, 2016)

And here: Air pollution exposure found to be risk factor for type 2 diabetes (Green Car Congress, Sep. 8, 2016)

Today we review research from Germany which examined the level of air pollution at the places of residence of 3,000 participants and how this relates to blood marker levels such as impaled glucose metabolism and the risk of Type 2 diabetes. Results indicate that a 7.9μg/m3 increment in particulate matter <10μm was associated with insulin resistance and that NO2, in particular, had a highly significant effects with pre-diabetic individuals as opposed to those who were either diabetic or not.

type-2-diabetes-and-pm

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Must Cities Shrink to be Sustainable, even with Increased Urbanization?

Sustainability for Shrinking Cities (9 page pdf, Dustin L. Herrmann, William D. Shuster, Audrey L. Mayer and Ahjond S. Garmestani, Sustainability, Editorial, Sep. 7, 2016)

 

Today we review an overview (and editorial) focused on sustainability for cities in the face of increasing urbanization worldwide and to the recent trend toward shrinking cities because of economic depression and the hollowing out of city centres as a result. Many large growing, economically-healthy cities tend to replace urban greenspace and urban parkland with high income residential or commercial developments with significant negative impacts on a healthy environment. Shrinking economically poor cities on the other hand are faced with vacant downtown lots some of which steer toward sustainable cities through improved water filtration, dampening of urban flash floods and carbon sequestration. For many coastal cities, sea level rise and threats to human health from more frequent hot spells as a result of climate warming are other issues on cities to adapt sustainably with more thoughtful urban planning.

shrinking-city

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Can the Paris Agreement on Climate Change Work?

The Paris Agreement and the New Logic of International Climate Politics (28 page pdf, Robert Falkner, International Affairs, Aug.31, 2016)

Today we review an analysis of the international negotiations from the top-down 1996 Kyoto Accord that today applies only to 15% of global carbon emissions, to the 2009 Copenhagen Accord that failed to reach consensus on a global emission reduction goal but managed to provide an umbrella for all participating countries for future negotiations. To the bottom-up Paris Agreement in 2015, signed by 195 nations, combines domestic politics with international commitments through a “naming and shaming” approach, voluntary national commitments,  rachet-up reviews every five years and, perhaps most importantly, definition of a long term goal to reach “net-zero” emissions or “emission neutrality” between 2050 and 2100. As these voluntary commitments would result in a global warming of 2.7 C above pre-industrial levels, further reductions beyond the pledges are needed. The author cautions that “the Paris Agreement cannot be expected to ‘fix’ the climate problem; it can only provide a supportive framework within which states and other actors can achieve the required emissions cuts.”

Carbon emissions from various global regions d...

Carbon emissions from various global regions during the period 1800–2000 AD (Photo credit: Wikipedia)

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