Friday, September 28, 2012

Traffic Air Pollution and Heart Disease in Denmark

Traffic air pollution and mortality from cardiovascular disease and all causes: a Danish cohort study (29 page pdf, Ole Raaschou-Nielsen, Zorana Jovanovic Andersen, Steen Solvang Jensen, Matthias Ketzel, Mette Sørensen, Johnni Hansen, Steffen Loft, Anne Tjønneland and Kim Overvad, Environmental Health, Sep. 5, 2012)

Today’s review concerns the link between air pollution from traffic near residences of people in Denmark and heart disease, taking into account the other effects of noise, diet and other items. Results indicate a significant link with air pollution which is lessened in those with a higher diet of fruits and vegetables.  

Key Quotes:

 “air pollution could affect the risk for cardiovascular disease through mechanisms involving systemic oxidative stress and inflammation, which could drive atherosclerosis progression and other long-term effects as well as serve as triggers of events through changes in vascular function”

 “among those living at locations with high NO2 levels, more were single or divorced, were smokers and exposed to environmental tobacco smoke, less physical activity, used hormone replacement therapy and were exposed to a higher noise level”

 “Dietary intake of fruit and vegetables modified the association between NO2 and mortality, so that the association was strongest for people with a low intake of fruit and vegetables and weakest (or absent) among people with a high intake.. A possible mechanism for a protective effect of fruit and vegetables that are rich in antioxidants and related compounds is scavenging of free radicals and reactive oxygen species generated by exposure to air pollution before they can affect vascular function”

 “Traffic air pollution is associated with mortality from cardiovascular diseases and all causes, after adjustment for traffic noise. The association was strongest for people with a low fruit and vegetable intake”
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Wednesday, September 26, 2012

Evaporating Traffic

Disappearing traffic? The story so far(10 page pdf, S. Cairns, S. Atkins and P.Goodwin, Proceedings of the Institution of Civil Engineers Municipal Engineer 151, March 2002)

 Also discussed here: Traffic Evaporation(One Street Blog, Resources for Increasing Cycling)

And here: Reclaiming city streets for people - Chaos or quality of life?(52 page pdf, European Commission, And here: Braess's paradox(Wikipedia)

In past reviews, we have looked at how congestion pricing reduces both congestion and improves air quality in the urban core. Today we examine another approach, widely used in Europe over the last 20-30 years, which combines the removal of road capacity and adding pedestrian areas to the space freed up. The results from 70 case studies in European cities and New York City point to the many improvements and reduced congestion with examples from the UK, Germany, France, Denmark, Belgium and other countries. Vehicle emissions in downtown areas decreased by 15-30% one year after road removals.  

Key Quotes:

 “taking away space for cars can improve traffic while making the city safer and more enjoyable for everyone on foot. There are sound theories that help explain why this happens -- concepts like traffic shrinkage and Braess's paradox which are getting more and more attention”

"For each point of a road network, let there be given the number of cars starting from it, and the destination of the cars. Under these conditions one wishes to estimate the distribution of traffic flow. Whether one street is preferable to another depends not only on the quality of the road, but also on the density of the flow. If every driver takes the path that looks most favorable to him, the resultant running times need not be minimal. Furthermore, it is indicated by an example that an extension of the road network may cause a redistribution of the traffic that results in longer individual running times." (Braess’s Paradox)
  • When roadspace for cars is reallocated, traffic problems are usually far less serious than predicted.
  • Overall traffic levels can reduce by significant amounts.
  • Traffic reduction is partly explained by recognising that people react to a change in road conditions in much more complex ways than has traditionally been assumed in traffic models.”
“‘Instead of wide, noisy streets in and out of the city and six storey underground parking all over the city centre, Copenhagen has opted for fewer cars and an extremely attractive city centre... Today the city of Copenhagen has over 96 000 m2 (of which 33 % is street and 67 % city squares) of car-free space.. In the city centre, 80 % of all journeys are made on foot, and 14 % by bicycle.Car traffic in the city core has been reduced and congestion is not a problem.”

 “[Nuremburg, Germany]After one year, traffic monitoring revealed that overall traffic flow in the historic city was reduced by up to 25 %, and the increase in traffic in adjacent streets proved very limited, ranging between 4 and 19 %, well below experts’ forecasts (in some cases a decrease was observed)..there was an overall reduction of approximately 10 000 vehicles between 1989 and 2000, despite an overall increase in car ownership during this period ….in the historic city centre emissions of nitrogen dioxides decreased by about 30 %, carbon monoxide and particulate matter by about 15 % — this was predominately driven by pedestrianisation..”
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Monday, September 24, 2012

The Status of Road Tolls in Europe

Tolling of cars in the European Union (Road pricing, Aug. 30, 2012)

Also discussed here: Truck tolls/HGV road user charging in the European Union (Road Pricing, Aug. 29, 2012)

Today we summarize a post from the blog “Road Pricing” that describes the present state of tolls in the 27 countries that make up the European Union (excluding Norway and Switzerland) which are divided into two categories: cars and trucks and into two approaches: charging by time (vignette) or distance (VMT). At present there are 13 countries with tolling systems for cars and 7 for trucks with 1 more planning for cars
  and 4 more for trucks.

Key Quotes:  

The clear trends are to either have extensive conventional (manual) tolled highway networks, or to charge for access to their networks either by time or distance”  

For Cars

Toll with physical barriers (distance-based charge) - 6 Member States have extensive toll road systems, using manual tolls (universally with electronic options). These being Ireland, France, Spain, Italy, Greece and Poland”

Vignette (time-based charge) - 7 Member States have vignette systems, whereby access is bought in advance for periods ranging from 4 days to one year. These countries are Austria, Czech Republic, Slovakia, Slovenia, Hungary, Romania and Bulgaria”

 “Vignette under preparation - Belgium is the only EU Member State currently considering introducing a vignette for private cars”

Electronic Network wide toll (distance based charge) - Curiously, Portugal gets this classification because it does have a growing number of fully electronic free flow toll roads”  

For trucks:

Vignettes (a charge based on pre-paying for access to the network for a period ranging from one day to one year). At present Bulgaria, Romania, Hungary and Lithuania have national vignette systems”

 “Countries developing vignette systems. At present, the UK and Latvia are both developing vignette systems”

 “Electronic network wide tolling (with distance charging) In the US this might be called "VMT". This covers both GPS based and DSRC based distance tolling. It includes the well known examples in Germany, Austria and the Czech Republic”

 “Countries developing electronic network wide tolling. Denmark, Belgium, France and Hungary”

Manual tolls. This seems to only include countries with significant amounts of tolling, as it includes Ireland, France, Spain, Italy, Slovenia and Greece only”
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Friday, September 21, 2012

Pollution Standards in the UK

Diesel Pollution(38 min, podcast, British Broadcasting Corporation Radio 4, Aug. 7, 2012)

Also discussed here: Transcript of “File On 4” – “Diesel Pollution” (20 page pdf, British Broadcasting Corporation Radio 4, Aug. 7, 2012)

 Today we review a broadcast on the BBC that includes interviews with leading British scientists involved with monitoring air quality, vehicle emissions and their impacts on health. Among several startling assertions is the observation that 40 out of 43 assessment zones fail to meet Euro 5 standards. Also, despite attempts by manufacturers to reduce diesel exhaust tail pipe emissions by improved filters, nitrogen dioxide emissions have increased five times due to start and stop driving and idling in increasingly congested
urban areas.


Key Quotes:

“While local measures to combat air pollution don't come cheap, it's the impact of bad air on health that costs the taxpayer most. Britain has the second highest death rates from some common respiratory diseases”

 “Modern diesel vehicles, to attempt to clean up the emissions of particles, they have had particle filters added and these are there with a primary purpose of reducing the tail pipe emissions of particles…But in urban driving conditions, with lots of stop-start driving and emissions during idling phases, they're not effective and therefore emissions of oxides of nitrogen are much higher”

 “at how many other sites in the city are the EU limit values being breached, do you think? PARRY: All the sites that we‟ve got on main arterial roads into the city, there's problems with the nitrogen dioxide”

“a major or the major factor prompting bronchiolitis among babies in the winter here is nitric oxide and most of it comes from vehicles? EVERARD: That would be our expectation”

 “Forty out of the UK‟s forty-three assessment zones are failing to meet EU targets”
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Wednesday, September 19, 2012

Where Does Air Pollution Gather in the Urban Environment?

Town roads Mystic urban area : Towns of Stonin...
Town roads Mystic urban area : Towns of Stonington-Groton, Connecticut / prepared by the Connecticut State Highway Department ; in cooperation with the Bureau of Public Roads, Department of Commerce 1956 (Photo credit: uconnlibrariesmagic)

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.  

Key Quotes:
pollutant particles, rather than scattering randomly, prefer to accumulate in specific regions of the urban environment and even form coherent structures”

 “researchers were able to verify this by using a new mathematical formula, the first of its kind, to simulate the long-term random motion of pollutant particles as would be found in the real world”

“The results can be used to generate maps of well and poorly mixed regions and highlight urban areas that are most susceptible to high concentrations of pollutants”
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Monday, September 17, 2012

Monitoring Air Pollution in Schools

Hand-held CO2 monitors could improve school air quality(Helen Albert, medwireNews, Aug. 23, 2012)

Also discussed here: Portable FID Model 115 (4 page pdf, Portable FID For Method 21 and Environmental Monitoring of VOC’s including methane, PID Analyzers)

As one of the most vulnerable to air pollution impacts, school children may be exposed to levels of pollution that present a health hazard. Today we review a new portable monitor that can be used to monitor these levels and if they are elevated, take measures to control or reduce them. The device provides for up to three
  weeks without recharging.

Key Quotes:

"Poor air quality in school classrooms is a growing concern.. as over exposure to carbon dioxide (CO2) can result in excessive drowsiness, inattentiveness, and in the worst cases hypercapnia."

“in the past, the typical number of air exchanges in a school classroom was in the range of four to six per hour, whereas a more modern "energy efficient" classroom may only have one to two air exchanges per hour”
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