Pollution Free Cities

Monday, December 16, 2013

How Does Population Dynamics Affect the Vulnerability and Resilience of Cities to Climate Change?

The Demography of Adaptation to Climate Change(204 page pdf, Martine, George and Daniel Schensul (eds.), United Nations Population Fund (UNFPA), IIED and El Colegio de Mexico, Oct. 2013)

Also discussed here: (1hr 49 min You-Tube, Woodrow Wilson Center, Oct. 2, 2013)

Today we review a comprehensive and up to date book on population trends and dynamics and how they affect the resilience and vulnerability of cities to climate change, the vulnerability of coastal cities to storms, cities in drylands to water shortages and how urbanization and sprawl combine with a lack of mobility to affect the poor, especially during severe climate events which may occur at greater frequencies. Although the focus is on urban areas in developing countries in Africa, Asia and Latin America, many of the conclusions or predictions apply equally well to highly developed countries, such as after Hurricane Katrina where the New Orleans poor could not afford fuel to flee disaster even if they had cars. “Climate change is a spatial phenomenon” but the link with urban population vulnerability is hampered because censuses are based on administrative divisions, not environmental risk which is becoming more definable by the advent of Geographic Information Systems and satellite mapping imagery.

Key Quotes:

“Mobile populations have more adaptive capacity, to the extent that mobility is a component of adaptation by way of reducing exposure”

“The high estimates of international climate migrants have been largely dismissed as unfounded by migration researchers … this crisis narrative is ideologically rooted and obscures more legitimate concerns about how the burdens of climate change are being distributed”

“in 2005, about 40 million inhabitants (about a tenth of the total population in these port cities) were exposed to one-in100 year coastal flood events…by 2070, climate change, subsidence, population growth and urbanization would increase this figure to about 150 million.”

“Overall, drylands cover 40 per cent of the world’s land area and, in 2000, contained about a third of the world’s urban population and also about a third of its rural population”

“densities in the built-up urban areas declined at about 2 per cent a year, though with a small but significant decline in urban fragmentation..more densely settled cities are likely to emit less carbon than otherwise comparable low-density cities. Concentrated settlements also create opportunities for increasing resilience to climate change”

“supporting migration as adaptation to climate change can only be successful if the context-specific links between migration and vulnerability are also addressed.”

“Urban areas are, on the whole, more resilient to climate variability because they favour economic productivity, the generation of employment and, on the aggregate, greater access to social benefits—all of which enhance the capacity of urbanites to adapt to climate change… urban areas are adding growing masses of population groups that are often the most vulnerable to climate change—the urban poor in exposed areas”

“The collision course between massive traffic problems and increasingly violent climatic events as a result of global climate change presages a magnification of the progressively more severe man-made ‘natural’ disasters in large Brazilian cities. Already, flash floods periodically wash away cars and pedestrians caught on lower-level street areas, while also invading households and buildings in the area.”

Friday, December 13, 2013

How will Future Ways to Produce Energy Impact Water Supply?

The Water Demand of Energy: Implications for Sustainable Energy Policy Development(14 page pdf, Saeed Hadian and Kaveh Madani, Sustainability, Nov. 5, 2013)

Today we review a paper that examines the type of sources needed to meet the 40% increase in global energy demand and what this implies in terms of a 37 to 66% increase in demand for fresh water. While the search for pollution-free cities in this blog has been on ways of reducing air pollution and usually concludes that non-polluting renewable energy sources are optimum, some of these sources (such as corn and ethanol) have a disproportionate demand for water - as high as 400 times higher than from conventional fossil energy sources. Some sources, such as solar energy, appear to have few if any negative impacts from energy generation but, if one looks at the water impact from the manufacture of photo-voltaic cells, the overall impact changes. The impact on water from fracking natural gas also needs scrutiny from this aspect. The paper being reviewed is based on a water footprint index made up of a blue, green and grey components, referring to the rainwater or surface water consumed during production or the water used for dilution to maintain water quality standards.

Shares of energy sources in world’s total energy supply (a) 2012; (b) 2035.

Key Quotes:

“global energy consumption is estimated to rise from 77 million BTU (81.2 GJ) per capita in 2012 to 91 million BTU (96 GJ) per capita in 2035, resulting in 40% increase in global energy use in the next two decades “

“ecological footprint exceeded biocapacity by 44% in 2006 and is estimated to exceed the biocapacity by 100% in 2030”

“In the U.S., the energy sector is expected to be the fastest growing water consuming sector, being responsible for 85% of the increase in domestic water consumption in the 2005–2030 period “

“Water footprint is a reliable measure for this purpose and represents the amount of freshwater used to produce one unit of energy from a given energy source:

blue water footprint, which is the volume of surface and ground water consumed in the energy production process;
green water footprint, which represents the volume of rainwater consumed during the production process (related to evapotranspiration and the rainwater incorporated in crop or wood);
gray water footprint, which represents the amount of freshwater required to dilute the pollutants such that the quality of water remains above given water quality standards. “

“governmental ethanol subsidies and mandates in the U.S. are aimed to increase the biofuel supply while the water footprint of this type of energy might be 70–400 times higher than the water footprint of conventional fossil energy sources. “

"the amount of water required for total energy production in the world will increase by 37%–66% during the next two decades, requiring extensive improvements in water use efficiency of the existing energy production technologies, especially renewables.”

Wednesday, December 11, 2013

How can Mobile Phones be used to Estimate Air Pollution Exposure?

Mobile phone tracking: in support of modelling traffic-related air pollution contribution to individual exposure and its implications for public health impact assessment(26 page pdf, Hai-Ying Liu , Erik Skjetne, Mike Kobernus, Environmental Health, Nov. 4, 2013)

Today we review a paper that explores an approach that uses personal mobile phones equipped with GPS tracking ability to estimate the exposure of a group of individuals to air pollution and make these estimates available in real-time at low cost. Such a method could be applied in developing countries where expensive monitoring equipment is often unaffordable. The potential of gathering information such as this from a wide segment of society also opens up very large opportunities for progress in public health by collective tracking of large numbers of people.

Key Quotes:

“Based on a synthesis of the best available evidence, the HEI (Health Effects Institute) identified that an exposure zone within a range of up to 300 to 500 metres from a major road as the area most highly affected by traffic emissions”

“we propose a conceptual framework to improve exposure assessment by using existing, low cost mobile phone data to obtain individual trajectories to further estimate the concentration of the traffic emission in the roadway network and its contribution to exposure for the urban population.”

“This approach is promising due to the following characteristics:

Low cost: There is no cost from the observation part. .. Combination of low cost and standardized mobile phone data makes it is feasible to do population-wide traffic pollution studies….
Near real-time: The system is based on fully automatic calculation and real-time data. One may obtain real-time pollution/exposure fields. This allows identification of high vehicle density congestion events that may contribute significantly to health risk
Effortless citizen participation: Each trajectory reflects one individual citizen. … We believe that using the trajectories of individual mobile phones opens up new perspectives on urban dynamics and public health research.

Monday, December 9, 2013

Is There a Need for Standards for Brief Peaks of Air Pollutants?

Peak event analysis: a novel empirical method for the evaluation of elevated particulate events(12 page pdf, Aaron Orkin, Pamela Leece, Thomas Piggott, Paul Burt, Ray Copes, Environmental Health, Nov. 1, 2013)

Today we review research into the occurrence of brief peaks of suspended particles (or dust), how often they occur (in a rural area of southern Ontario) and if the results point to a need for standards for periods of less than an hour- the shortest time period currently used in Canada and many other countries. The resulting analysis showed that peak values of PM10 twenty to one hundred times greater than values averaged over an hour which were within the current standards. Although the aim of the research was to examine single events with high associated levels of pollution, one cannot help but wonder what the health impacts would be for people exposed to repeated doses of high pollution for shorter periods than are covered by existing standards, such as proximity to roadside emissions at rush hour each day. If there is a definable health impact, that would both call for standards for shorter periods- say 10 minutes or one minute- and might explain the degree of mortality associated with traffic (which has been estimated as about 1/3 of all deaths from outdoor air pollution in a study conducted by the City of Toronto Medical Officer of Health).

Key Quotes:

“In occupational settings, brief and even singular exposures to high levels of irritant dust, vapour, fume or smoke has, in patients with no prior history of respiratory disease, been described as the causative agent in reactive airways dysfunction syndrome and irritant-induced asthma, resulting in symptoms of airway inflammation and bronchial reactivity without a latency period”

“Canadian standards identify 1-hour mean limits for sulphur dioxide, ozone, nitrogen dioxide, and hydrogen sulphide, but do not place limits on relatively brief peak allowances for PM2.5 or PM10 by defining limits at the 98th percentile or through 24-hour and annual means”

“We analysed these data from a public health perspective in order to determine if local air quality complaints could be traced to elevated particulate levels.”

“Our novel methodology revealed extreme outlier events above the 99th percentile of readings, with peak PM10 and TSP levels over 20 and 100 times higher than the respective mean values.”

Friday, December 6, 2013

How Quickly are Cities Growing and What are the Environmental Consequences?

Choking on their own growth(24 page pdf, Lars Martin Hjorthol, pages 17-20, Gemini, NTNU, spring 2013)

Today, we review an article in « Gemini », the magazine of NTNU, the technical university located in Trondheim, which has formed a multidisciplinary group of researchers looking at “urban ecology”. The article looks at the population growth of cities, especially in Africa and Asia, over the last 50 years, how urban development has proceeded and what needs to be done in the future. A major observation is that traditional Western development policy with its accent on sprawling suburbs, has unfortunately took hold in some cities. Urban development must be adapted bottom-up to the particular needs of the inhabitants who see secure property ownership as most important along with health safety and transportation.

Key Quotes :

"Almost the entire global population increase over the next decades will take place in the cities of the south. The population in cities has increased fivefold since 1950, increasing by 60 million a year, according to UN figures…By 2050, there will likely be well over nine billion people on Earth, 70–75 per cent of whom will live in cities …In 1950, all of Africa’s cities combined had a population of 33 million. But that number may grow to as much as 1.3 billion by 2050,”

“Everything seemed chaotic. And I thought like a traditional urban planner, with ready made solutions to what I perceived as the main problems. But what we first thought was most important to people in the area, proved to be far down on their priority list. Their top priority is more secure property ownership and tenancy,”

“Instead of asking what does not work, we start with what they have, and build on local resources. We have to build on their strengths, not their weaknesses,”

“The greater the degree of urbanization, the stronger the economy. Europe and the US have an urbanization rate of nearly 90 per cent. China passed the tipping point of having 50 per cent of its population as city dwellers in January 2012 and will probably exceed 70 per cent by 2050.”

“Internal inequality is a major cause of many problems in rapidly growing cities, when it comes to health, safety, transportation and other infrastructure,”

“But the Chinese are still stuck in a traditional Western planning paradigm, with suburbs and car-based land use. This approach is already about to collapse in several places. We see almost no bicycles in Beijing anymore. Instead, cars are stuck in endless queues, and move much more slowly than bikes used to do,”

“Major cities in developing countries often have higher emissions of greenhouse gases per person than in rural areas (while the opposite is often true in developed countries).”

“Urbanization has not been covered in this way in previous IPCC reports. Now there’s a chapter on urbanization in both the sub-report on emissions reductions and in the chapter on adaptation,”