Pollution Free Cities

Thursday, July 21, 2016

Microspatial Hotspot Variability of Urban Air Pollution

Use of an exposure model to explore the impact of residential proximity to a highway on exposures to air pollutants of an ambient origin (Abstract, Woodrow Pattinson , John Langstaff, Ian Longley, Simon Kingham, Atmospheric Environment, May 2016)

Today we review research into the distribution of air pollution at a higher resolution than many urban studies, looking at how it changes during the day and within neighbourhoods and between streets in New Zealand’s capital city of Auckland. Fixed air monitoring stations either close to traffic or away from it tend to miss high resolution pollution hotspots both in time and space. In this study, a specially instrumented bicycle was used to measure carbon monoxide (CO) and particulate matter (PM10) over different times of the day and for different streets in an area that was subdivided by a highway with traffic. Results indicated that while emissions from highway traffic dominated the morning rush hour, that the queued stop and go nature of street level pollution reached a peak during the mid-day and afternoon. Studies such as this need to be considered for the placement of populations whose health is at risk due to air pollution, such as early childhood centres and the elderly in retirement homes (which should be separated by at least 100 m from major roads).

Key Quotes:

“For major highways …long-term average concentrations of UFPs, nitrogen oxides (NOx) and black carbon (BC) tend to be at least 50% higher within the first 50-100 m than sites further from the highway …This results in significantly elevated long-term exposures for residents living within this zone of influence.”

“studies have reported an association between poor urban air and diabetes prevalence, exacerbation of asthma in young children and more rapid cognitive decline in the elderly.. Where possible, the placement of …early childhood centres, schools, retirement homes and social housing projects next to high-emission zones should be avoided. Some researchers are now advocating for a complete separation of at least 100 m between all residential buildings and major roads”

“mobile monitoring methods are becoming increasingly popular due to the relative low-cost and ability to capture data at high spatial resolutions.”

“diurnal change in PM10 for both areas, with some evidence of highway-traffic increasing concentrations during the morning rush hour. The mobile plots also show evidence of heavy vehicle influence at the arterial routes during the midday …and afternoon periods"

“local street traffic has a dominant influence during the day and domestic burning at night/early morning, in turn diluting the signal from the road network …CO emissions factors are in fact lower for highway traffic than for street traffic due to the highest emissions occurring under heavy acceleration, and the stop-go nature of street level driving, possibly explaining the peak events within our CO plots.”

“We have also been able to clearly illustrate the shifting spatial impact of the freeway (decreasing during the day) and the importance of arterial routes during the midday and afternoon periods….due to a combination of higher winds trapping plumes within street canyons and the direct emissions from queued stop-start traffic within the canyons themselves.”

Tuesday, July 19, 2016

What Impact Do Local Emission Controls have on Air Pollution?

Response of SO2 and particulate air pollution to local and regional emission controls: A case study in Maryland (16 page pdf, Hao He, Konstantin Y. Vinnikov, Can Li, Nickolay A. Krotkov, Andrew R. Jongeward, Zhanqing Li, JeffreyW. Stehr, Jennifer C. Hains, and Russell R. Dickerson, Earth’s Future, AGU, Apr. 12, 2016)

Today we review the changes that emission controls implemented in the state of Maryland with the Healthy Air Act in 2009, had on the concentration of SO2 and PM2.5 using measurements from satellites in space as well as ground measurements over the last 10 years. Results indicate that emissions from (coal burning) power plants were reduced by 90% while concentrations of SO2 were reduced by 50% and PM2.5 by 25%- with all of the decline of PM2.5 due to a reduction in sulphur. Results were striking in the decrease of the seasonal peak of SO2 in mid summer when there is a higher power demand. The difference between the greater SO2 emission reduction and concentration reductions shows the added input to the pollution from other than power plants (such as diesel vehicle emissions).

Key Quotes:

“SO2 has been linked to respiratory ailments ..Its residence time, also called atmospheric lifetime, in the lower atmosphere ranges from ∼2 days in the winter to less than 1 day in the summer .. anthropogenic SO2 emissions come mainly from power plants and other coal combustion facilities and have decreased by ∼6%/yr in the last decade…. Sulfate aerosols from SO2 usually peak in summer …and historically account for 50%–60% of the ground-level PM2.5 observed in the eastern United States “

“PM2.5,the main source of air pollution mortality in the United States..is mainly removed in precipitation processes and has an atmospheric lifetime of about 10 d. PM2.5 is also responsible for haze, which usually dictates the limit of visual range .. impacts the hydrological cycle ..and affects the weather and climate” “Peak PM2.5 concentrations are observed in the summer, when the rate of oxidation of gaseous precursors, SO2, and volatile organic compounds (VOC) to particulate matter peaks.”

“Essentially, all of the improvement in PM2.5 can be attributed to the decline in sulfate. The decrease (1.7 μgm−3, 42% out of 4.1 μgm−3) in sulfate is smaller than that for total PM2.5 (2.5 μgm−3, 20% out of 12.7 μgm−3), but most of the sulfate in the eastern United States is neutralized, and when corrected for the greater molecular weight of (NH4)2SO4 (132 g/mole) compared to SO4 2– (96 g/mole), the resulting change is −2.4 μgm−3 and can account for most (93%) of the observed drop in PM2.5.”

“The Healthy Air Act, implemented in Maryland in 2009–2010, provided an exceptional opportunity to test the impact of a step change in local emissions on ambient pollution levels. This Maryland regulation reduced in-state power plant emissions of SO2 by ∼90%; long-term aircraft measurements, surface observations, and satellite products showed a reduction in column SO2 of ∼50%, while PM2.5 and AOD showed a reduction of ∼25%.”

Thursday, July 14, 2016

What Links Urban Metabolic Energy Flows and Urban Ecosystems – a literature review.

Eight energy and material flow characteristics of urban ecosystems (12 page pdf, Xuemei Bai, Ambio, Apr. 22, 2016)

Today we examine a review of current literature about two apparently conflicting urban concepts: one that is concerned with the material energy flows, the other with the ecology of wildlife and plants in a city environment. As cities become more complex and larger these concepts become more important in themselves, as well as between each other with intercity distributions and the regulation of processes across large urban areas and estimating the capacity of a city when to comes to the flow of materials, such as waste Approaching cities in this way also allows for a better defined environmental footprint, as demonstrated in one example in Barcelona, where a park designed for carbon sequestration was found after analysis to be one twelve the size needed to produce the desired absorption of carbon emissions from the city. The concluding words are worth noting: “A better understanding of the interactions between anthropogenic material and energy flows and ecosystem processes can help reduce unintended consequences of narrowly focused policy and management decisions.”

Key Quotes :

« The concept of urban metabolism has been widely used to study energy and material flows into and out of cities… recent urban energy and material flow studies have extended far beyond the original metaphor of cities as organism, and started to reveal important characteristics of urban system features and interactions.. Urban energy and material flow efficiency can be defined as how much social/economic services per unit of resource consumption or waste generation can support. It shows how efficient the urban system is in supporting its function, and is an important system performance indicator.”

“The input part of the urban metabolism includes various tangible materials such as food, water, construction and other materials, products, energy, as well as inflow of energy, capital, information, and people. Such input supports societal activities and drives urban functions within a city; forms urban stocks such as housing, building, infrastructure, and green parks; and produces products and services, as well as managed and unmanaged waste and emissions.”

“The output part consists of industrial products, services, knowledge, and various wastes and emissions. The magnitude, distribution, and internal interactions and feedbacks are regulated by policy, governance, culture, and individual and collective behaviour of the urban system.”

“Understanding biogeochemical budgets of ecosystems, in particular nutrients such as carbon, nitrogen, and phosphorus, has been one of the crucial elements of urban ecology” “The metabolic budget can be used to assess the total ecological footprints of cities”

“The total budget and pathways of material and energy flows reveal the magnitude of impacts and other important characteristics of urban system, such as the functional role of the city, development stages (i.e., mature or growing city), level of infrastructure and development, income, and other socioeconomic characteristics of the city”

Tuesday, July 12, 2016

What is the Impact of Hydraulic Fracturing?

Fracking Communities (22 page pdf, Colin Jerolmack and Nina Berman, Climate Change and the Future of Cities: Mitigation, Adaptation, and Social Change on an Urban Planet, Public Culture, Duke University Press, May 2, 2016)

Also discussed here: Fracking Hits Milestone as Natural Gas Use Rises in U.S. (Bobby Magill, Climate Central, May 6, 2016)

Today we review an article that chronicles the impact fracking has and is having on rural communities and the natural forests and parks that lie among them. Although fracking natural gas (and closing coal plants) has been credited with the 12% reduction in CO2 in the USA from 2007 to 2012, the process involves over 1,000 truckloads of water for just one well and 1,020 shale wells have been approved in Pennsylvania alone. More than 15 million Americans in 11 states live within a mile of a fracked well. New York is the only state where municipal bans are legal. As methane is 20 times more radiatively active in the atmosphere than CO2, leaks of more than 3% from a well eliminate the greenhouse gas benefit that methane enjoys over emissions from coal.

$fracking traffic$

Key Quotes:

“While it has long been known that vast reserves of natural gas (and oil) lay locked in layers of shale a mile or more underground, most of it remained inaccessible until this century, when the process of hydraulic fracturing — also known as fracking — was combined with horizontal drilling. "

“for the first time last year, natural gas contributed about the same level of greenhouse gas emissions as coal, the globe’s largest single source of greenhouse gas emissions driving climate change…Sixty-seven percent of natural gas produced in the U.S. came from fractured wells in 2015, according to the data. That represented a total of 53 billion cubic feet of natural gas per day, up from 50 billion cubic feet in 2014”

“because methane (the primary component of natural gas) is a greenhouse gas whose potency is more than twenty times that of CO2 over a hundred-year period, even a relatively small rate of methane leakage (i.e., 3 percent) from the production and distribution of shale gas could “offset or even reverse the entire apparent greenhouse gas benefit of fuel switching from coal to natural gas”

“the proposed culprit in most reports of health impacts is air pollution, resulting from gas wells, compressor stations (which serve as nodes for area wells that pressurize the gas), and diesel engines venting volatile organic compounds — including known toxins such as benzene and formaldehyde — into the atmosphere next to residences, communal gathering places, and parks”

“more than 15 million Americans in eleven states live within one mile of a fracked well … approximately 700,000 acres of state forest are “available” for natural gas development… has approved 232 well pads (each capable of hosting up to twenty-four wells) and 1,020 shale gas wells since 2008”

“It takes over one thousand truckloads just to deliver the water needed to frack one well, and a single well pad can host as many as eighteen to twenty-four gas wells”

“the tragedy of the commons engendered by private oil and gas leasing in rural communities works directly against the kind of collectivist politics needed to prevent our planet from lapsing into abrupt and irreversible climate change”

“For shale gas extraction to be “sustainable,” it must do more than burn “cleaner” than coal: it should foster the resilience of common-pool resources and the communities that host it.”

Thursday, July 7, 2016

How Could the USA Become Carbon Neutral by 2050?

100% clean and renewable wind, water, and sunlight (WWS) all-sector energy roadmaps for the 50 United States (Abstract, Mark Z. Jacobson, Mark A. Delucchi, Guillaume Bazouin, Zack A. F. Bauer, Christa C. Heavey, Emma Fisher, Sean B. Morris, Diniana J.Y.Piekutowski, Taylor A. Vencill and Tim W.Yeskoo, Energy and Environmental Science, May 27, 2015

Also discussed here: Here's what it would take for the US to run on 100% renewable energy (David Roberts, Vox Energy and Environment, May 3, 2016)

Today we review a report that details how the USA could reach 100% renewable energy sources by 2050 and what cost and benefits would be needed to accomplish that. 80-85% of existing carbon energy sources would be replaced by 2030 and the rest by 2050 with 49% wind power, 45% solar power and the remainder hydroelectric, geothermal, tidal and wave power. Benefits include $7.1 trillion per year in avoided climate impact losses due to US emissions and $600 billion per year in avoided health costs. The approach includes more emphasis on public transit and safer walking and cycling, mandating battery electric vehicles for short and medium distance driving, an expansion in the number and distribution of electric charging sites as well as a time of use that favours night time charging, and electrification of freight rail.

Key Quotes:

“This study presents roadmaps for each of the 50 United States to convert their all-purpose energy systems (for electricity, transportation, heating/cooling, and industry) to ones powered entirely by wind, water, and sunlight (WWS). The plans contemplate 80–85% of existing energy replaced by 2030 and 100% replaced by 2050.”

“Year 2050 end-use U.S. all-purpose load would be met with ∼30.9% onshore wind, ∼19.1% offshore wind, ∼30.7% utility-scale photovoltaics (PV), ∼7.2% rooftop PV, ∼7.3% concentrated solar power (CSP) with storage, ∼1.25% geothermal power, ∼0.37% wave power, ∼0.14% tidal power, and ∼3.01% hydroelectric power.”

“Converting would further eliminate ∼$3.3 (1.9–7.1) tril. per year in 2050 global warming costs to the world due to U.S. emissions.”

“These plans will result in each person in the U.S. in 2050 saving ∼$260 (190–320) per year in energy costs ($2013 dollars) and U.S. health and global climate costs per person decreasing by ∼$1500 (210–6000) per year and ∼$8300 (4700–17600) per year, respectively.”

“Switching from liquid fuels to renewable electricity would also virtually eliminate air pollution, thus avoiding health costs to the tune of $600 billion a year by 2050.”

“ moving everything to carbon-free electricity would avoid about $3.3 trillion a year in global climate change costs of US emissions by 2050.

Tuesday, July 5, 2016

All about Carbon Pricing: Carbon Tax? Cap and Trade?

Putting a Price on Carbon: A Handbook for U.S. Policymakers (56 Page pdf, Kevin Kennedy, Michael Obeiter, And Noah Kaufman, World Resources Institute, Apr. 2015

Today we review a handbook to implement carbon pricing- either by tax or by cap and trade- in the USA. Among the points noted were that a low to moderate tax alone would be “highly unlikely” to meet the UN’s goal of keeping global warming to less than 2 C (as recommended by 195 states at COP21 in Paris). Technological innovations subsidized by government are also needed and these can be funded from carbon tax revenue as well as other benefits such as tax cuts, return of money to households and electric users, and helping those directly harmed by carbon taxes as well as reducing national debt. Canada and the USA are well behind Scandinavian countries (such as Denmark, Finland, Norway, and Sweden, beginning in the early 1990s) to establish a national carbon tax, although at the sub-national level, California and Western states, British Columbia, Alberta, Ontario and Quebec have started to price carbon in recent years. Another interesting point is that a moderate carbon tax of $28/tonne applied to the USA would impact low income earners by 2.5% (and high earners by only 1%). This identifies the need to neutralize the regression effects by subsidizing the low income group by this amount.

Key Quotes:

"A carbon price would lead to reductions in U.S. greenhouse gas emissions and create leverage to encourage other countries to reduce their emissions, both of which are necessary to prevent the more severe effects of climate change. In addition, reduced fossil fuel usage will provide “co-benefits” in the form of reduced emissions of other harmful air pollutants.”

Some Potential Benefits of Carbon Tax:

TAX CUTS. The revenues from carbon pricing could be used to fund cuts in other tax rates. …
RETURNING MONEY TO HOUSEHOLDS OR ELECTRICITY CONSUMERS. Revenue from carbon pricing could be returned to households by sending them “lump sum” payments, which could be divided equally or by some alternative metric….
DEFICIT REDUCTION….. Carbon pricing revenues could be used to reduce annual deficits and thereby help to avoid such adverse economic effects.
INVESTING IN COMBATING CLIMATE CHANGE. In addition to its potential to stimulate innovation in low-carbon technologies (for example, renewable energy), a carbon price can provide revenue to help promote the development and deployment of breakthrough technologies
TRANSITIONAL ASSISTANCE. A portion of the revenues can be used to assist those likely to be most adversely affected by a carbon price…”

“A carbon tax is in some ways simpler than a cap-and-trade program. A tax does not require the government to allocate or conduct auctions for emissions allowances, or monitor the trading of allowances, and regulated entities do not need to participate in auctions or secondary markets for allowance trading.”

“The major advantage of a cap-and-trade program is that the policy sets a firm limit on the quantity of emissions that will be allowed.”

“It is highly unlikely that a low to moderate carbon tax would achieve the level of emissions reductions the Intergovernmental Panel on Climate Change (IPCC) recommends in order to prevent the worst impacts of climate change”

“The longest-running programs are the carbon taxes established by Denmark, Finland, Norway, and Sweden in the early 1990s. National carbon taxes have also been established in recent years in France, Iceland, India, Ireland, Japan, Mexico, Switzerland, and the United Kingdom,”

“Government support of research, development, and demonstration of measures to reduce emissions from energy, transportation, agriculture, or other sectors can fill the gap created by private sector under-investment, and help bring down the costs of breakthrough technologies. This, in turn, could help to drive more cost-effective emissions reductions and reduce the cost of complying with the carbon tax.”

“CBO has found that a carbon tax of $28 per metric ton of CO2 emissions would increase after-tax costs for the average household in the lowest quintile of the income distribution by 2.5 percent; for households in the top quintile, the carbon tax would increase after-tax costs by only one percent.”