Modelling Cities According to Isobenefits

Simulating future societies in Isobenefit Cities: Social isobenefit scenarios(16 page pdf, Luca D’Acci, Futures Journal, Sep. 25, 2013)

Today we review a paper about a model of various urban forms that are evaluated according to the benefits that each confers to its citizens. The forms include a traditional Central Business District form where the population and economy is highest in the centre and radiates outward to a second form where there are several sub centres or sub cities of activity to a third form where there is a ring city surrounding .The isolines of benefits (isobenefits) are based on formulae which estimate such things as benefits to pedestrians and cyclists (pedestrian and bike paths for example) and specific examples from cities around the world are tested. Results indicate the types of cities that could be designed as well as what might be done to existing cities to improve benefits. The optimum one seems to be a multi-centre city.


To see Key Quotes and Links to key reports about this post, click HERE

How Does Waste Heat from MegaCities Affect the Global Atmospheric Circulation?

Energy consumption and the unexplained winter warming over northern Asia and North America(5 Page pdf, Guang J. Zhang, Ming Cai and Aixue Hu, Nature Climate Change, Jan 27, 2013)

Also discussed here: Cities change temperatures for thousands of miles(UCAR ATMOS News, Jan. 27, 2013)

And here: City heat affects temperatures 1,000 miles away(The Times of India, Jan. 28, 2013)

Today we review global climate modeling research that examined the contribution of the waste heat produced by buildings and vehicle emissions in very large cities. Although this heat is small compared to the warming from greenhouse gasses in the atmosphere for the entire world, the model simulations reveal large changes in the regional circulation near these cities which may intensify local weather events such as droughts or extreme storms.


To see Key Quotes and Links to key reports about this post, click HERE

Where Does Air Pollution Gather in the Urban Environment?

The geometry of inertial particle mixing in urban flows, from deterministic and random displacement models (Abstract, Wenbo Tang, Brent Knutson, Alex Mahalov, and Reneta Dimitrova, Physics of Fluids, American Institute of Physics , Jun. 25, 2012)

Also discussed here: Wind Concentrates Pollutants With Unexpected Order in an Urban Environment(ScienceDaily, Aug. 24, 2012)

Today an interesting paper is reviewed that describes a physical-mathematical urban wind model  that showed how the shape and form of the urban structure affect where pollutants tend to accumulate or gather. This is doubly important – first, as a clue on where to locate pollution monitors and, second, where to expect higher levels of pollutants with health impacts. The implications for urban design and planning are obvious.

Town roads Mystic urban area : Towns of Stonin...To see Key Quotes and Links to key reports about this post, click HERE

Pollution “Radar” and the London Olympics

Sensors to create 3D map of Olympic pollution levels  (Mark Prigg, London Evening Standards, Apr. 30, 2012)

Also discussed here: UK develops technology to study traffic impact during London Olympics (Road Traffic Technology, May 1, 2012)

And  here: CityScan – The Pollution Radar

And here: 3-D Map of Air Pollution in London (London Air, King’s College London)

The site of each Olympics, it seems, is in or near a large city with high pollution levels.This year is no different with London following Beijing. By no coincidence, national authorities take steps to monitor and  improve the air quality not only for the competing athletes but also for the millions of visitors to the event. Today we review progress on the development of a compact optical device, a “pollution radar”, which can produce time sequenced 3D maps of  NO2 for the entire city with a resolution of 50m and 5 minutes from three monitoring sites.

To see Key Quotes and Links to key reports about this post, click HERE

Hamilton’s Air Pollution Hot Spots

Mobile Air Quality Monitoring to Determine Local Impacts  (39 page pdf, Denis Corr, Rotek Environmental Inc. July 2011)

Also discussed here: Unique study maps neighbourhood air pollution  (Hamilton Spectator, Jan. 20, 2012)

And here: A Public Health Assessment of Mortality and Hospital Admissions Attributable to Air Pollution in Hamilton  (3 page pdf, School of Geography and Geology and McMaster Institute of Environment and Health, 2011)

From the city of Hamilton, a leader among Canadian cities in the assessment of urban health, comes a report on a local neighbourhood air quality monitoring study. Results indicate almost 12% increased mortality risk as an average across the city for all pollutants, with the highest increased risk (+18%) near the 6 lane highway (403) that bisects the city. The breakdown of risk by pollutant may also be used to identify and reduce pollution sources.

To see Key Quotes and Links to key reports about this post, click HERE

The State of Air Pollution in Europe

The European Environment – State and Outlook 2010 – Air Pollution (46 page pdf, European Environment Agency, 2010)

The report reviewed today is an overview of the progress (or lack of progress) being made or forecast in Europe to meet EU objectives. Clearly, the main challenge has to do with particulate matter and nitrogen dioxide and managing the main sources: hydro plants and transportation. One striking observation is that as electric vehicles are introduced to reduce urban emissions, rural areas may suffer as the sites of expanded electric generating utilities.

To see Key Quotes and Links to reports about this post, click  HERE

The Application of Air Quality Models in Europe

The application of models under the European Union’s Air Quality Directive: A technical reference guide  (76 page pdf, European Environment Agency, Sep. 2011)

Today’s focus is on the application of air quality models in Europe, noting the limitations and benefits of models in combination with ground-based or space-based monitors. There are several very useful tables showing the policy standards for a range of air pollutants for various applications and scales.

To see Key Quotes and Links to key reports about this post, click HERE

Can Simulation Modelling Steer Us toward Sustainability?

Cover of "The Limits to growth: A report ...

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Virtual Sustainability (16 page pdf, Sims Bainbridge, W. Sustainability 2010, 2, 3195-3210, Sep. 30,2010)

Models simulating  the ways that people interact with the natural world and themselves have long been used to create scenarios that allow environmental and economic policies to be tested. The World 2 model was developed Jay W. Forrester in 1970, using system dynamics techniques to examine global energy and consumption trends, and led to the “Limits to Growth” book from the Club of Rome. The article reviewed today takes that concept further by examining social interactions in an online multi-player environment to test such propositions as telecommuting.

To see Key Quotes and Links to key reports about this post, click HERE

Classifying Assessing Health Impacts from Urban Air Pollution Differences

Time series: random data plus trend, with best...

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Implications of different approaches for characterizing ambient air pollutant concentrations within the urban airshed for time-series studies and health benefits analyses (26 page pdf, Matthew J Strickland, Lyndsey A Darrow, James A Mulholland, Mitchel Klein, W DANA Flanders, Andrea Winquist and Paige E Tolbert, Environmental Health 2011, 10:36, May 11, 2011)
Today’s review article examined the consequences in terms of health impacts in using a single centrally located urban air quality measurement compared to several measurements and how these measurements were weighted. Cautions are noted that centrally located monitors may indicate higher levels of pollutants than the average of several. When assessing health impacts of vulnerable subpopulations, such as the elderly and children, a weighting system that takes this into account would likely more useful than an unweighted average.

To see Key Quotes and Links to key reports about this post, click HERE

Modelling Exposure to Health Risks from Air Pollution

Combining Regional- and Local-Scale Air Quality Models with Exposure Models for Use in Environmental Health Studies (12 page pdf, Vlad Isakov, Jawad S. Touma, and Janet Burke, Danelle T. Lobdell, Ted Palma, Arlene Rosenbaum, Haluk Ozkaynak, Journal of the Air & Waste Management Association, Vol. 59:461– 472, Apr. 2009)


Today’s focus is on ways of measuring the exposure of humans to air pollution and the models being used to assess the health risks, including the EPA’s Community-Focused Exposure and Risk Screening Tool (C-FERST), the Hazardous Air Pollutant Exposure Model [HAPEM] and the Stochastic Human Exposure and Dose Simulation [SHEDS] model. The noted links point to reports that describe how each functions. One conclusion is that the complex patterns and gradients in air pollution across a city requires more than one or two representative measurement points if one needs to adequately define the health risk to urban communities.

To see Key Quotes and Links to reports about this post, go to the new internet platform for Pollution Free Cities by clicking HERE

An Urban Air Pollution Simulator

Smog City

Today’s review is about a computer simulator from California showing ozone levels over a day as a function of population, temperature, amount of cars and trucks, industry etc.

To see Key Quotes and Links about this post, go to the new internet platform for Pollution Free Cities by clicking HERE

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Neural Network Modelling and Residential Building Energy Consumption

Analysis of a Residential Building Energy Consumption Demand Model (13 page pdf, Wei Yu, Baizhan Li, Yarong Lei and Meng Liu, Energies 2011, 4(3), 475-487, Mar. 10, 2011)


One of the largest sources of greenhouse gas emissions world-wide is the fuel used to heat (or cool) residences. Today’s review article uses advanced neural network modelling to analyse energy consumption for a large (32M population) city in southwestern China (Chongqing), using a set of 16 filtered indicators. Comparison of model results with actual ones showed less than 3% error and promise for further applications to optimize building energy consumption.

To see Key Quotes and relevant articles, go to the new site for Pollution Free Cities by clicking HERE

Modelling Rush Hour Emissions for Ottawa’s Major Roadways

Carleton University as seen from the Rideau River

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Development of a Methodology for Estimating Vehicle Emissions (416 page pdf thesis, Jennifer Armstrong, Carleton University, AMICUS service of Library and Archives Canada, Aug. 2000)


The report reviewed today is a ground-breaking thesis by a graduate student at Carleton University’s engineering school which won awards from the Ontario Ministry of Environment and the Professional Engineers of Ontario in 2001. The research brought together the vehicle emission data for the national capital area which included Origin-Destination municipal survey data, travel demand modelling, emission modelling and GIS mapping to produce maps of pollutants at peak travel times across the cities of Ottawa and Hull (now Gatineau). It shows quantitatively the importance of vehicle emissions particularly in the congested downtown and near the 6 –8 lane Queensway that  bisects the city of Ottawa.

To read more about this post, click HERE to visit the new internet platform for Pollution Free Cities

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Health Outcomes of Reducing the Local Air Pollution Burden

Feasibility of Assessing Public Health Impacts of Air Pollution Reduction Programs on a Local Scale: New Haven Case Study (31 page pdf, Lobdell DT, Isakov V, Baxter L, Touma JS, Smuts MB, Özkaynak H, Environ Health Perspect, 18 Feb.18, 2011)



Today’s review article examines the feasibility of applying air quality modelling to the task of estimating health benefits resulting from improvements in air quality at the local level as a result of various strategies and programs. The conclusions point to the usefulness of this approach which was tested by scenarios running out 20 years into the future. This appears to a very useful tool as well for evaluating policy choices for improving urban air quality.

To read more of this post click HERE at Pollution Free Cities new internet platform

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3D Forecasts of Air Quality – PREV’AIR

PREV’AIR -An Operational Forecasting and Mapping System for Air Quality in Europe (11 page pdf, Bulletin of American Meteorological Society, Jan. 2009)

Also discussed here: PREV’AIR

Key Quotes:

“[French] local authorities in charge of air pollution can now inform the public and take emergency decisions related to air pollution control not only on the basis of measurements, but also by accounting for numerical forecasts”

“three main functions of the PREV’AIR system:

  1. The “forecasting” function delivers forecasted atmospheric concentrations of ozone, particulate matter (PM10 and PM2.5), and nitrogen oxides, simulated throughout Europe at low resolution (0.5° × 0.5°) and over France with a higher resolution (0.15° × 0.1°).
  2. The “analysis” process uses available near-realtime observations to build the “analyzed” maps that are considered as the most realistic description of pollution patterns.
  3. The “performance evaluation” function of the system uses observation data that are routinely acquired for continuous evaluation of the model forecasts, with descriptive indicators given online. Every day, statistical skill scores (bias, errors, percentage of errors lower than a certain level, and correlation) are calculated and updated on the PREV’AIR Web site”

“In case of a pollution episode, when concentrations exceed the regulatory thresholds, PREV’AIR forecasts are broadcast on television channels to enhance public information.“

“system provides real-time information about air pollutant concentrations throughout Europe, with a focus on France, which is particularly relevant to health prevention in acute pollution episodes.“

“Air quality forecasting and mapping is an efficient tool for authorities in charge of air quality management. Anticipating pollution events with concentrations exceeding regulatory levels allows them to inform the general public and to decide emergency control measures.”

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Atmospheric Chemistry Processes in Smog Formation

Predicting Smoggiest Days: Experiments Improve Accuracy of Ozone Predictions in Air-Quality Models (Science Daily, Oct. 28, 2010)

Also discussed here: Rate of Gas Phase Association of Hydroxyl Radical and Nitrogen Dioxide (Abstract, Science, Vol. 330. no. 6004, pp. 646 – 649, Oct. 29, 2010)

Key Quotes:

“The reaction of OH and NO2 to form gaseous nitric acid (HONO2) is among the most influential in atmospheric chemistry….We demonstrate the impact of the revised value on photochemical model predictions of ozone concentrations in the Los Angeles airshed.”

“The key reaction in question in this research is between nitrogen dioxide and the hydroxyl radical.. Until about the last decade, scientists thought these two compounds only combined to form nitric acid, a fairly stable molecule with a long atmospheric life that slows ozone formation”

“researchers found the loss of hydroxyl radical and nitrogen dioxide is slower than previously thought-although the reactions are fast, fewer of the radicals are ending up as nitric acid than had been supposed, and more of them are ending up as peroxynitrous acid.”

“a small but significant impact on the predictions of computer models used to assess air quality, regulate emissions and estimate the health impact of air pollution,”

“the laboratory results suggest that, on the most polluted days and in the most polluted parts of L.A., current models are underestimating ozone levels by 5 to 10 percent”

“a 10 part-per-billion increase in ozone concentration may lead to a four percent increase in deaths from respiratory causes-any increase in expected ozone levels will be important to people who regulate emissions and evaluate health risks”

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Modelling Air Quality in an Urban Canyon

Estimation of CO concentrations for an urban street canyon in Ireland (8 page pdf, Air Quality, Atmosphere & Health, Mar. 5, 2010)

Today’s review article looks at the performance of two canyon air quality models – STREET and OSPOM – when compared with stationary monitor located near a busy roadway in Dublin. In addition an assessment is made using emission factors (HEF for hourly and CEF for Composite) to judge the models as to the emissions from the source

Key Quotes:

“The WHO has estimated that 1.4 billion urban residents in developing countries breathe air in which pollutant concentrations exceed WHO air quality guidelines (WHO 1992). Urban air pollution episodes are associated with sudden incidences of high concentrations of pollutants, which are generally governed by local meteorology, emissions and dispersion conditions (Mayer 1999). The major source groups responsible for urban air pollution are primarily motor traffic and industries”

“In most European cities, traffic is the most important source of air pollution, with the highest ambient concentrations often found on streets in urban centres. Vehicular pollution dispersion models are therefore essential computational tools for predicting the impacts of emissions from road traffic”

“two urban street canyon models, namely STREET and Operational Street Pollution Model (OSPM), were investigated at Pearse Street, an important traffic route in the centre of Dublin city

“Hourly background concentrations were obtained from an urban air quality monitoring station.. approximately 100 m from the nearest trafficked street. All this recorded parameters were used in computing the modelled CO concentrations. These were then compared with measured CO concentrations”

“An emission factor is the relationship between the amount of pollution produced and the amount of raw material processed or burned. For road traffic, it is the relationship between the amount of pollution produced and the number of vehicle kilometres travelled (grams per kilometre). By using the emission factor of a pollutant and specific data regarding quantities of materials used by a given source, it is possible to compute emissions for the source”

“This paper tries to highlight the STREET model as a suitable screening model for the prediction of CO concentrations in an urban street canyon. When compared with monitored data, concentrations calculated using STREET and OSPM both successfully predict observed variations in air quality”

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Neuro-fuzzy Urban Air Quality Modelling

Haze over Kuala Lumpur.
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Adaptive neuro-fuzzy modeling for prediction of ambient CO concentration at urban intersections and roadways (10 page pdf, Air Quality, Atmosphere & Health, May 19, 2010)

Modelling of urban air pollution has developed from purely statistical to deterministic but today’s article focuses on neuro-fuzzy techniques which bridges the use of “expert” modelling techniques from artifical intelligence research to estimate extremes as well as average concentrations- in this case, for carbon monoxide at the street/intersection level.

Key Quotes:

“There has been a substantial growth in road traffic over the years and that has resulted in increase in air pollution. In many cities across Europe, USA, Japan, China, and Singapore, vehicular exhaust emissions (VEEs) are now considered as one of the most important sources of urban air pollution”

“screening, assessment, and prediction of ambient air pollutant due to VEE in such urban corridors has become an essential requirement as a part of an efficient local/episodic urban air quality management plan”

“environmental damage is caused both by extreme as well as by the average concentrations of pollutants. Hence, the models should predict not only ‘extreme’ ranges but also the ‘middle’ ranges of pollutant concentrations, i.e., the entire range.”

“Two types of forecast models have been developed. The first model uses a fuzzy expert system and forecasts the possibility of high O3 concentration. The second model uses a neural network system to forecast daily maximum concentration of O3 on the following day”

“The fuzzy models are capable of analyzing linguistic information and efficiently carry out programming/processing with improved knowledge representation and uncertainty reasoning. In addition, the neuro-fuzzy modeling technique can interpret and analyze any kind of information (numeric, linguistic, and logical) and possesses self-learning, self-organizing, and self-tuning capabilities, thus improving the quality of forecasts. The present study was under taken to develop models for CO based on neuro-fuzzy approach for different seasons”


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Life-Cycle Assessment of Nanotechnology and Health

Jay Wright Forrester
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Sustainable Nanotechnology: Through Green Methods and Life-Cycle Thinking (16 page pdf, Sustainability 2010, 2(10), 3323-3338, Oct. 25, 2010)

Before futurist Jay W. Forrester at MIT, developed the “World” model for the Club of Rome in 1970, he focussed on the same Systems Dynamic approach by applying it to an urban setting.  Many years later, we are still learning that a cradle-to-grave approach is needed to build pollution-free sustainable cities, especially with the advent of electronic devices such as TVs and cell phones, whose lifetimes are measured in weeks or months. The result of this and even greater miniaturization is an ever growing mountain of highly toxic materials which form part of either urban waste centres or shipments to even bigger mountains in China, India and other countries, as discussed in this post E-Waste

The article reviewed today assesses the life cycle of nanotechnology with some interesting observations such as the need to identify health impacts as soon as possible in development of these devices.

Key Quotes
“Sustainability and futures studies are linked to each other; the time scales involved may be different from the individual viewpoints of stakeholders, depending on whether they are futurists environmentalists. Futures thinking calls for planning in the time scale of hundreds of years whereas the environmental research community may think in terms of a few decades at the most”

“the need to conduct ―life cycle-based assessments as early in the new product development process as possible, for a better understanding of the potential environmental and human health consequences of nanomaterials over the entire life cycle of a nano-enabled product”

“The wide-ranging applications of nanotechnology have an equally widespread potential to adversely affect human health and the environment, through various exposure routes of nanoparticles, including occupational exposure”

“nano-based products that seem environmentally preferable over other alternatives in the Use stage may not actually turn out to be so when the whole life cycle is considered”

“the effects on human health and the environment are characterized based on environmental loadings… calculated using formulas based upon quantities of pollutants discharged to air, water, and land.”

Risk Assessment goes from quantities of pollutants discharged to analyzing their effects under ambient conditions, through various exposure pathways”

“current Life-Cycle Assessment methodology, developed for use with conventional bulk materials, needs to be reconsidered and modified, if necessary, to make it suitable for evaluating nanomaterials”

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Modelling Urban Air Pollution Hot Spots

Modelling Urban Traffic Air Pollution Dispersion (The International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences. Vol. XXXVII. Part B8. Beijing 2008)

The article being reviewed today addresses the need for local authorities to know the distribution of urban air pollution both in the horizontal, as reported in Ottawa Air Quality Information System and in the vertical. The result is a system which authorities can use to identify the extent of hot spots and potential health threats along roadways, as well as vertically in buildings along the road.

Key Quotes:

“The prime aim of this research is to support decision making, e.g., air quality impact analysis, human health assessment, through spatially modelling traffic-induced air pollution dispersion in urban areas at street level. “

“composed of basically three parts: an urban base data model, a dispersion model with a spatial database and a 3D GIS environment for visualisation. “

“local authorities are facing the challenge of being responsible for effective counter measures if limit values of air pollution are exceeded.. need ‘high-resolution’ information on air pollution levels that give not only the pollution levels for few measurement stations within a city (macro-level) but also pollution levels for the individual streets (micro-level). “

“Providing information about traffic air pollution and finding out its distribution is therefore a crucial starting point for planning effective measures to improve air quality…The location of hot spots of high pollution levels that exceed a certain threshold has besides a horizontal also a vertical dimension; the latter is usually neglected. ”

“a warning line that represents where pollution limit value is exceeded can be used to calculate the number of floors affected as well as allow an estimation of the number of influenced inhabitants. “

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Speed vs. Frequency- what counts most?

Applying Highway Concepts to Transit (Human Transit, Apr. 16, 2010)

Also discussed here: Illusions of Travel Time in Transit Promotion (Human Transit, Mar. 28, 2010)

Secondary reference:  AASHTO GREEN BOOK – A Policy on Geometric Design of Highways and Streets, 5th Edition

When assessing options for transit , there is need to think differently than for road traffic management according to a very interesting post by Jarrett Walker on his blog – with consequences when it comes to the impact on air quality that results from inefficient choices. On a related topic access vs. mobility, Walker points out the need to live close to those things that are desirable.

Key Quotes:

“when people talk about vehicle speed as though it were much more important than frequency.  For cars it is.  For most urban transit it isn’t, with the exception of the most rigidly scheduled commutes.”

“An interstate highway has great mobility (manifested as high speeds), but poor accessibility (wide spacing in interchanges).  Meanwhile local streets have the opposite – poor mobility (low speeds), but high accessibility (numerous intersections, curb cuts, etc).”

“the balance between distance (which requires speed) and stop spacing (which causes delay)”

“frequency, a concept of paramount importance in transit that has no analogue in motoring, apart from the small waits required by signal cycles”

“mobility is how far you can go, while access is how many desirable things you can do”

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Global Mortality Impact of Air Pollution

An Estimate of the Global Burden of Anthropogenic Ozone and Fine Particulate Matter on Premature Human Mortality using Atmospheric Modeling ( 36 page pdf, Environ Health Perspect, 09 April 2010)

A key reference and estimate of the overall impact of particulate matter and ozone on worldwide deaths.

Key Quotes

“estimate the global burden of mortality due to O3 and PM2.5 from anthropogenic emissions using global atmospheric chemical transport model simulations of preindustrial and present day (2000) concentrations to derive exposure estimates.”

“Using simulated concentrations rather than previous methods based on measurements allows the inclusion of rural areas where measurements are often unavailable and avoids making assumptions for background air pollution.”

“While O3 and PM2.5 concentrations have increased most in industrialized areas, observations show that background concentrations have also increased in remote regions“

“PM2.5 mortality estimates are about 50% higher than previous measurement-based estimates based on common assumptions”

“Estimated PM2.5 mortalities are five times O3 mortalities, suggesting PM2.5 is the dominant contributor to the global health burden of outdoor air pollution.“

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Air Pollution – Health Effects Methodology

Air pollution
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Case-Crossover Analysis of Air Pollution Health Effects: a Systematic Review of Methodology and Application (47 page pdf, Environ Health Perspect, 31 March 2010)

Key Quotes:

“systematic review of case-crossover (CCO) designs used to study the relationship between air pollution and morbidity and mortality, from the standpoint of methodology and of application..first systematic review to cover the application of case-crossover designs to the study of the health effects of air pollution.“

“The dependent variables most frequently analyzed were those relating to hospital morbidity, while the pollutants most studied were those linked to particulate matter.“

“The papers published by Lee et al. (1999) and Neas et al. (1999) were the first studies to report the relationship between air pollution and mortality, using a CCO design. These studies performed a re-analysis of the effects of air pollution and mortality in the cities of Philadelphia and Seoul, respectively, obtaining a relationship that proved statistically significant.“

“The use of CCO designs has undergone considerable growth, with the most widely used designs being those that yield better results in simulation studies, namely, symmetric bidirectional and time-stratified CCO”

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London Air Pollution in 3D

This short video shows the relationship between roadside emissions and the city of London‘s topography and building architecture- as well as the future direction of the merging of Geographical Information System (GIS) data bases with air pollution monitoring and mapping.

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Can Highway Barriers Contain Pollution from Traffic?

Tracer studies to characterize the effects of roadside noise barriers on near-road pollutant dispersion under varying atmospheric stability conditions (Atmospheric Environment, Volume 44, Issue 2, January 2010, Pages 204-214)

Discussed here: Highway Barriers Stifle Sound, Sight, and Soot (Science Daily, Jan. 5, 2010)

Also discussed here Highway Barriers Stifle Pollution (the earthy report, Jan. 8,2010)

Key Quotes:

“to systematically and comprehensively investigate the role of atmospheric stability in real world conditions on the movement of pollutants near highway barriers”

“the barriers ..reduce high concentrations of pollutants from those vehicles by lifting and channeling them away from the adjoining areas, often a residential area,”

“Researchers were able to conduct tracer studies in unstable, neutral and stable atmospheric conditions in tightly controlled circumstances, to quantify the effects of roadside barriers on pollutant dispersion”

“We also found that the barriers tended to trap pollutants in the area of the roadway itself, especially at night in low wind speed conditions.. The amount of pollutants was much higher on roadway areas flanked by barriers than in areas without them.”

“The study did not assess the impact on drivers who are exposed to higher levels of pollutants while driving through these barriers”

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Satellite-based Estimates of Aerosol Optical Depth and Particulate Matter

What Can Affect AOD–PM2.5 Association? ( 2 page pdf, Environ Health Perspect,  Mar.1, 2010)

Also discussed here:

Limitations of Remotely Sensed Aerosol as a Spatial Proxy for Fine Particulate Matter (6 page pdf, Environ Health Perspect, June 2009)

Key Quotes:

“The columnar measurement of AODS consists of aerosols generated by anthropogenic (human) sources …is influenced by moving large air masses and observes a strong spatial and temporal structure.”

“The concentration of PM2.5, however, can vary significantly within short distances. Therefore, there is a significant mismatch in the magnitude and extent of spatial and temporal variability of AODSn and AODS”

“Recent literature suggests that 1-km and 5-km AODS observe a significantly better association with PM2.5 monitored on the ground than the 10-km AODS”

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Forecasting Air Pollution with Artificial Neural Networks

3-Day-Ahead Forecasting of Regional Pollution Index for the Pollutants NO2, CO, SO2, and O3 Using Artificial Neural Networks in Athens, Greece (15 page pdf, Water Air Soil Pollut, 29 Aug 2009)

Key Quotes:

The goal of this study is the construction of models, using ANNs, which give the possibility of forecasting the maximum daily value of an ambient air pollution index for NO2, CO, SO2, and O3, for seven different measuring sites of Greater Athens Area (GAA) and for the next three consecutive days, as well as the daily number of consecutive hours with the pollutants above a threshold concentration.

ANNs are a branch of artificial intelligence developed in the 1950s aiming at imitating the biological brain architecture. They are parallel-distributed systems made of many interconnected nonlinear processing elements (PEs), called neurons

we created two different ANNs. The first one (ANN#1) was trained in order to forecast the daily maximum value of the ERPI (for the pollutants CO, NO2, SO2, and O3) for seven different measuring sites in GAA, at the same time, 3 days ahead. The second one (ANN#2) was trained in order to forecast the number of the hours, during the day, with at least one of the pollutants concentrations (CO, NO2, SO2, and O3) above a threshold according to directives of European Union,

The models ability to predict reliably 3 days ahead, the excesses or non-excesses days (days with the limit value of ERPI50), for the year 2005, according to the values of the success index ranges between 84.6% (Liossia 3-day-ahead prediction) and 92.2% (Patission 1-day-ahead prediction).

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The benefits of reducing 1 ton of air pollution

The influence of location, source, and emission type in estimates of the human health benefits of reducing a ton of air pollution (8 page pdf)

Key Quotes

“The benefit per ton ($/ton) of reducing PM2.5 varies by the location of the emission reduction, the type of source emitting the precursor, and the specific precursor controlled. This paper examines how each of these factors influences the magnitude of the $/ton estimate.”

“This heterogeneity is a product of source location, meteorology, mix of pollutants emitted, and atmospheric conditions, including baseline atmospheric concentrations of pollutants.”

“Three inter-related sources of heterogeneity affect the magnitude of PM2.5 $/ton estimates.

The first relates to the chemical processes that govern the formation of PM2.5 in the atmosphere….

The second source of heterogeneity relates to the characteristics of the emitting source…

The third factor that may influence the heterogeneity in PM2.5-related $/ton estimates is the size of the population exposed to PM2.5 and the susceptibility of that population to adverse health outcomes.”

“It should be noted that, while NOx reductions may occasionally generate PM2.5 disbenefits in certain urban areas, because NOx is also an O3 precursor, additional NOx reductions—even in areas where PM2.5 disbenefits are possible—may produce a downwind O3 benefit.”

“The PM2.5 $/ton estimates in this paper reflect three principal sources of heterogeneity:

Variability across precursors. The $/ton for certain pollutants, such as directly emitted PM2.5, is much higher than others…

Variability across sources. Certain sources may emit a common precursor, but may produce very different $/ ton estimates…

Variability across location. The $/ton for a given pollutant showed some degree of variation based on the urban area in which the pollutant was emitted.”

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Planning Future Cities

A new urban planning tool, MetroQuest ,  is being used to create scenarios for the next few decades and examine the future trends and links between transportation, housing, water, education, jobs, air quality, and many other quality-of-life issues.

Regional Air Quality Snapshot (51 page pdf- May 2009) for Chicago.


“This Regional Air Quality Snapshot describes current air quality conditions, sources, regulations, and efforts specific to northeastern Illinois. Our region is currently in nonattainment with federal standards, meaning it does not meet the requirements of the Clean Air Act and exceeds healthy air pollution levels. But the region’s air quality has shown improvement, and there are numerous efforts in the region and the state to improve air quality.”

The Chicago Metropolitan Agency for Planning (CMAP) has a web site which demonstrates how this tool is being used for their GO TO 2040 Plan.


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The Greenhouse Effect (1896)

On the Influence of Carbonic Acid in the Air upon the Temperature of the Ground (22 page pdf)

“Arrhenius’s paper is the first to quantify the contribution of carbon dioxide to the greenhouse effect and to speculate about whether variations in the atmospheric concentration of carbon dioxide have contributed to long-term variations in climate”

Arrhenius estimated that if the combustion of fossil fuels were to result in a doubling of atmospheric CO2 levels, global temperatures could rise 5 deg. C,  just a little more than recent estimates over 100 years after his research was published.

Svante Arrhenius was the first Swede to win the  Nobel prize in chemistry in 1903.

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Health Effects of Near-Roadway Air Pollution (EPA)

EPA Research Focus – Health Effects of Near-Roadway Air Pollution (AWMA-Aug, 2009- 5 page pdf)

- exciting new EPA study on health impacts within 300 ft of heavy traffic. The quote below about schools near freeways needs to be considered by planners in cities, such as Ottawa and Toronto, bisected by  major highways  which run very close to many many schools with children vulnerable to exposure from the emissions.

Key Quotes:

“With the goal of improving programs and activities at the federal, state, and local levels, the plan addresses several points along the pathway from source to health outcome: characterization and apportionment of sources and emissions, air quality, exposure assessments and modeling in a variety of micro-environments, and health effects.”

“an estimated 45 million Americans live within 300 feet of a highway”

“recent research suggests that near-road exposure may even initiate asthma”

“Near-road air has higher concentrations of ultrafine particles, resulting from fresh combustion emissions, and coarse particles, resulting from tire/brake wear and resuspended road dust.”

“Something was going on close to the freeway. There was more allergenicity in the particles at 50 m.”

“Factors affecting ambient particle concentrations, such as roadway configuration and wind direction, should also be addressed.”

“When I look around and see us building more schools near freeways, I just think we have to do better as a society.”

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Traffic Congestion and Emissions

An Examination of Congestion in Road Traffic Emission Models and Their Application to Urban Road Networks

This 393 page PhD thesis by Robin Smit examines traffic emission models (such as the Canadian EMME traffic demand model)and the extent to which they represent congestion as a factor, using actual traffic data from Brisbane, the 3rd largest city in Australia.

He concludes that congestion is important in modelling such emissions as CO and Hydrocarbons (HC) while basic traffic composition is more important in modelling NO2 emissions.


posure studies, as well as urban air quality assessment and management. …

Ottawa probably has the basic tools to develop a similar GIS based mappng system here to assess health risk from trafffic

Air pollution at street level in European cities

“Air pollution at street level in European cities”
European Environment Agency, Copenhagen , 2005 (52 pages)

Executive Summary:
“Traffic-related air pollution is still one of the most pressing problems in urban areas. Evidence of the adverse health effects of fine particulate matter is continuously emerging and it is alarming that most of the traffic-related emissions are in the fine particulates range (< PM2.5). Human exposure to increased pollutant concentrations in densely populated urban areas is high. The improvement of air quality is therefore imperative. Air quality limit values, which are aimed at protecting public health, are frequently exceeded especially in streets and other urban hotspots.”

” It aims to determine which local emission reductions are needed in streets in order to reach certain air quality thresholds.”

Comment-this report has a focus on the largely unmeasured hot spots which exist in many downtown urban areas

Predicting Air Quality at Street Level – A State-of-Science Review

“Predicting Air Quality at Street Level – A State-of-Science Review”
by RWDI AIR Inc. Consulting Engineers(2008, 30 pages)

SUBMITTED TO: Mr. Gord Miller, Environmental Commissioner of Ontario

Key Quote:
“These measurement and forecast systems have proven useful to advise the public about large scale smog events, but do not deal with public exposure to pollutants at a local or street level. Large numbers of people in urban centres are exposed, at least for parts of their day, to air pollution at street level where vehicle emissions may be trapped in the canyon created by large buildings on either side. As such, the exposure to pollutants at street level is typically very different from the regional average exposure measured at monitoring stations and predicted by computer models.”

1) The MOE should consider expanding the ambient air quality network in a few select cities to better understand local air quality impacts related to major traffic corridors..”

Welcome to Smog City 2

Welcome to Smog City 2
Using an interactive air pollution simulator to control the air quality in Smog City 2, you can see how individual choices, environmental factors, and different types of land use affect air pollution. …




Within the framework of the international RTD project WEBAIR (EUREKA E! 3266 EUROENVIRON), a web-based air quality assessment and management information system is being developed in collaboration of partners from 18 countries (




A series of pioneer modeling efforts have been undertaken to study the interactions of air quality and regional climate as part of USEPA’s “Intercontinental Transport and Climatic Effects of Air Pollutants” (ICAP) project. …
– extremely interesting look at links between projected climate scenarios and air quality- such as lower air pollution in areas of projected higher precipitation


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