Friday, May 31, 2013

Measuring Health Rate Variability near Traffic

English: Oxidative stress process Italiano: Pr...
English: Oxidative stress process Italiano: Processo dello stress ossidativo (Photo credit: Wikipedia)

PM2.5, oxidant defence and cardiorespiratory health: a review(15 page pdf, Scott A Weichenthal,Krystal Godri-Pollitt, Paul J Villeneuve, Environmental Health, May 4, 2013) 

Today we review research aimed at seeing if there is a significant link between oxidative stress and the cardiovascular health impacts, arising from exposure to high levels of PM2.5- and if so, the value of oxidative burden as a metric. Results indicate there is an inverse relationship between heart rate variability (HRV) and PM2.5 which may be useful when assessing health threats from proximity to vehicle emissions in heavy traffic.  

Key Quotes: 

“Of the plausible biological mechanisms explaining PM2.5 health effects, oxidative stress is often cited as playing an important role in both respiratory and cardiovascular outcomes”

 “Here we review epidemiological evidence related to the role of oxidative stress (and oxidant defence) in PM-induced cardiorespiratory morbidity.” 

“stronger inverse associations were observed between PM2.5 and HRV among subjects with genetic polymorphisms that impaired oxidant defence;” 

“a polymorphism in the enzyme needed to produce reduced glutathione (important for oxidant defence) was found to modify the impact of PM2.5 exposure on lung function growth among children,” 

 “Conceptually, PM oxidative burden is an appealing exposure metric for epidemiological analysis as it aims to capture the ability of PM to modify a biological process known to contribute to adverse cardiorespiratory health effects…. little evidence is available to gauge the potential role of this metric in ambient air quality management.” 

“oxidative potential measures from this assay have been shown to vary with proximity to important sources of air pollution such as traffic..and further evaluation of an expanded set of health outcomes with both acute and chronic exposure intervals are required before the validity of this measure can be fairly assessed.”
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Wednesday, May 29, 2013

How the Six Cities Paper was a Game Changer for Clean Air – a Lesson for Addressing Climate Change?

Prevailing winds - A decades-long fight to bring clean air standards in line with environmental health science offers lessons for today.(Harvard School of Public Health News, Fall 2012)

Also discussed here: An Association between Air Pollution and Mortality in Six U.S. Cities(7 page pdf, Douglas W. Dockery, C. Arden Pope, Xiping Xu, John D. Spengler, James H. Ware, Martha E. Fay, Benjamin G. Ferris, Jr., and Frank E. Speizer, The New England Journal of Medecine, Dec. 9, 1993)

And here: Harvard Six Cities Study Follow Up: Reducing Soot Particles Is Associated with Longer Lives(Harvard School of Public Health Press Release, Mar. 16, 2006)

Today we recall a paper published 20 years ago that caused a major shift in national public policy for regulating cleaner air and lowering emissions of fine particulate matter. Until it was published (in 1993), the link between mortality and air quality had not been established. After it was published, based on the survival rates in six cities over 14-16 years, new PM 2.5 standards were introduced that “would prevent 15,000 premature deaths annually”.

What is particularly interesting and relevant today to the “debate” about climate change is the need to present scientific data in a clear unambiguous manner (as it was in the six cities case) to avoid the delays introduced deniers looking for insignificant errors in raw data (which has been the situation for the last decade with the climate change issue). The International Panel on Climate Change (IPCC)
should  pay attention!
 six cities graph

Key Quotes:

“We provided the basis for quantifying how many hospital visits, how many asthma attacks, how many COPD [chronic obstructive pulmonary disease] cases, how many heart attacks, and how many deaths were associated with these air pollutants,”

“Residents of Steubenville, Ohio—the city with the dirtiest air—were 26 percent more likely to die prematurely than were citizens of Portage, Wisconsin, the city with the cleanest air.” “The effects of air pollution were about two years’ reduction in life expectancy….It was much, much higher than we had expected.”

“The EPA claimed the new PM2.5 rules would prevent 15,000 premature deaths annually and produce other huge benefits, among them preventing 250,000 incidences of aggravated asthma, 60,000 cases of bronchitis, and 9,000 hospital admissions every year.”

“because of Six Cities, it is conventional wisdom that particulate matter contributes significantly to a wide variety of illnesses across the spectrum of life, from asthma and bronchitis to sudden infant death syndrome and lung cancer.”

“We knew that if we released the data, it would be endless aggravation and defending against attacks….To have a hostile group combing through your data looking for anything to attack you about was not something any of us relished.”

“In 2009, Dockery and colleagues Arden Pope (now at Brigham Young University) and Majid Ezzati (now at Imperial College London) demonstrated that from 1980 to 2000, reductions in exposure to fine particulate matter had increased average American life spans by 1.6 years…If you got rid of all cancers, the net effect on average life expectancy would be two years.”
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Monday, May 27, 2013

How Healthy is the Air in Subways?

Culture-Independent Analysis of Aerosol Microbiology in a Metropolitan Subway System(32 page pdf, Charles E. Robertson, Laura K. Baumgartner, Jonathan K. Harris, Kristen L. Peterson, Mark J. Stevens, Daniel N. Frank, and Norman R. Pace, Appl. Environ. Microbiol., Mar. 29, 2013)

Also discussed here : How Gross Is the Air of the NYC Subway, Really?(Henry Grabar, the Atlantic - Cities, Apr 26, 2013)

Today we review some research into the quality of the air found in subways, not just the physical and chemical content, but also the microbiological properties in a rare glimpse in that direction. Results show that the air quality inside the tunnels closely resembles the outside air quality as a result of a highly efficient exchange of air by the movement of trains themselves called “train-pumping”. The differences that do exist are interesting: more aerosols made up of tiny metal particles generated by the metal wheels and tracks and skin flakes that are emitted by the people using the subways and generated by convection from their skins- but the density found is no worse than in similar gatherings of people in offices for example. Perhaps the most significant aspect of the study is to predefine the conditions of subway air before the possibility of a terror attack using microbiological substances. All of this is important. as more and more cities turn to Light Rail (LRT) to meet their transit needs in addition to those with Heavy Rail.


Key Quotes:

“The goal of this study was to determine the composition and diversity of microorganisms associated with bioaerosols in a heavily trafficked metropolitan subway environment.”

“There are lots and lots of regulations and pieces of information on aerosol chemicals and aerosolized particles in our society.. There’s no assessment of microbiological air quality.”

 “airborne particulate materials in subways are different from what is found on city streets or in other indoor environments. This is particularly due to aerosolized metallic dust, which most likely is generated by the action of iron train wheels on tracks”

 “our survey finds that the microbiota encountered in the NYC subway is fairly mundane, essentially a mix of outdoor air with an overlay of human-associated microorganisms typical of the skin.. this survey provides the pre-event information necessary for surveillance activities for pathogens that might occur or be introduced into the system.”

“The general uniformity of microbial assemblages throughout the system indicates good air mixing, a testimony to the efficiency of the train-pumping process.”
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Friday, May 24, 2013

The Impact of Proximity to Traffic on Birth Outcomes

Residential proximity to major roads and adverse birth outcomes: a hospital-based study (26 page pdf, Takashi Yorifuji, Hiroo Naruse, Saori Kashima, Soshi Takao, Takeshi Murakoshi, Hiroyuki Doi and Ichiro Kawachi, Environmental Health, Apr. 18, 2013)

Today we review research into the link between proximity to heavy traffic and low birth weight or preterm birth for a perinatal hospital located in Shizuoka, Japan. The results confirmed the association with proximity to high levels of air pollution as well as the influence of a second factor, low income (termed as low socio-economic position) which has also been shown to be significant.

Newborn child, seconds after birth. The umbili... 
Newborn child, seconds after birth. The umbilical cord has not yet been cut. (Photo credit: Wikipedia)

Key Quotes:

“Evidence has accumulated on the association between air pollution and adverse birth outcomes, such as preterm birth or low birth weight”
“Major roads were defined as those having total vehicle counts greater than 50,000 per 24 hours on a weekday”

“Living within 200 m from a major road increased the risk of preterm birth by 1.5 times… and LBW by 1.2 times”

Preterm births and LBW [low birth weight]were observed more often in areas closer to major roads. Additionally, younger and older mothers tended to experience more adverse birth outcomes, especially for term LBW”
“We observed that mothers from lower individual SEP[social economic position], defined by household occupation, had higher effect estimates for term LBW compared with mothers with higher individual SEP.”

“we found that maternal diabetic and hypertensive status modified the relationship between air pollution and preterm birth.”
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Wednesday, May 22, 2013

Climate Change and Urban Health in Developing Countries

Urban heat island profile
Urban heat island profile (Photo credit: Wikipedia)

Also discussed here: Addressing Urban Environmental Health and Maternal Mortality in Developing Countries(Maria Prebble, New Security Beat, Wilson Center, Apr. 24, 2013

Today we review a working paper from Norway that looks at the challenges facing urban centres in developing countries during after global climate change. While many of these cities have large slums which make the issue a matter of vulnerability and poverty, the link between climate change and health with specific impacts from heat and air pollution is the overriding challenge and what sort of governance is needed is the main question.  

Key Quotes:

Main findings from the review of climate change and health literature related to/in urban areas:
  • “is discussed as part of the broader and established research issue of environmental health;
  • there are potential co-benefits in treating climate change and health together;
  • equity issues are of concern to many authors”
“The health effects of climate change range from ‘cardiovascular mortality and respiratory illnesses due to heat waves, to altered transmission of infectious diseases and malnutrition from crop failures’”

“The health effects of climate change in urban areas have most notably been linked to the heat island effect, indoor and outdoor air pollution, coastal location, high population density and poor sanitation”

 “As ‘more than 70% of the urban population in sub-Saharan Africa live in slums’33, the focus on climate change and health in African cities is particularly concerned with vulnerable and poor populations.”

 “there is still a gap in research on how to govern the health effects of climate change in urban areas in developing countries.”

 "Policy recommendations and questions that need to be addressed:
  1. what structures/actors need to be involved;
  2. how they coordinate across actors representing different sectors;
  3. the multilevel dimension to this coordination and, subsequently,
  4. the urban governance of climate change adaptation that includes health;
  5. the equity aspect of this work."
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Monday, May 20, 2013

Particulate Pollution Near Traffic and Hardening of the Arteries

Fine Particulate Air Pollution and the Progression of Carotid Intima-Medial Thickness: A Prospective Cohort Study from the Multi-Ethnic Study of Atherosclerosis and Air Pollution(9 page pdf, Sara D. Adar mail, Lianne Sheppard, Sverre Vedal, Joseph F. Polak, Paul D. Sampson, Ana V. Diez Roux, Matthew Budoff, David R. Jacobs Jr, R. Graham Barr, Karol Watson, Joel D. Kaufman, PLoS Med, Apr. 23, 2013)
Also discussed here: Air Pollution and Hardening of Arteries(Science Daily, Apr. 23, 2013)

Today we review a paper that looks at the impact of PM2.5 levels in several cities across the USA on heart disease. Higher concentrations of PM often found during exposure to vehicle emissions near heavy traffic were found to have a significant link to atherosclerosis or hardening of the arteries and give rise to a 2% greater risk of a heart attack for those who live in these areas.arteries  
Key Quotes:

“higher concentrations of fine particulate air pollution (PM2.5) were linked to a faster thickening of the inner two layers of the common carotid artery, an important blood vessel that provides blood to the head, neck, and brain.”

"Our findings help us to understand how it is that exposures to air pollution may cause the increases in heart attacks and strokes observed by other studies,"

 “The researchers were able to link air pollution levels estimated at each person's house with two ultrasound measurements of the blood vessels, separated by about three years”

 "Linking these findings with other results from the same population suggests that persons living in a more polluted part of town may have a 2 percent higher risk of stroke as compared to people in a less polluted part of the same metropolitan area,"
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Friday, May 17, 2013

How can Intelligent Transportation Systems Reduce Traffic Congestion?

Congestion Management in the GTHA: Balancing the Inverted Pendulum (Chapter 1)(pages 3-41, Baher Abdulhai, Residential and Civil Construction Alliance of Ontario, Apr. 2013)

Also discussed here: Multi-Agent Reinforcement Learning Integrated Network Of Adaptive Traffic Signal Controllers (Marlin-ATSC)(44 page pdf, Samah El-Tantawy, presentation of PhD dissertation, University of Toronto, 2011)

And here: Making Traffic Smarter - An intelligent transportation system could reduce vehicle emissions in Toronto by as much as 30 per cent(John Lorinc, UofT Magazine, Spring 2013)

Today we review a report on the use of smart traffic lights to reduce waiting times at intersections by about 1/3 which in turn equates to significant reductions in greenhouse gases and toxic pollutants in urban areas. The systems use real-time learning to adjust and optimize signaling. smart stoplights

Key Quotes:

Intelligent Transportation Systems (ITS) help increase the effective capacity of infrastructure, manage demand, and maximize efficiency. … consists of a three-pronged approach:
  • capacity expansion where warranted,… We can never build enough lanes to completely eliminate congestion at all times and everywhere. Many people see building more roads as an unsustainable alternative.
  • demand management to rationalize use.. A little more demand may cause the freeway to slip into a stop-and-go pattern and lose some 25% of its capacity. Preventing this situation by imposing a dynamically varying fee means gaining back 25% capacity at the time we are desperate for it.
  • intelligent systems to dynamically enhance efficiency of the existing system, before building more or imposing harsh restrictions on users…A computer system that monitors a freeway and dynamically sets varying congestion pricing fee in real time, such that demand never exceeds capacity, will accommodate 25% more demand.”
“When a major freeway overflows, a fairly small percentage of diversion onto the streets can cause widespread congestion. This is the reason it is important to properly maintain high-capacity major routes throughout the city.”

“Developed at the University of Toronto, MARLIN is a state-of-the-art traffic signal control system. It is AI-based control software that enables traffic lights to self-learn and self-collaborate with neighbouring traffic lights to cut down motorists’ delay, fuel consumption, and the negative environmental effects of congestion.”

“traffic data collected at 59 downtown locations in 2009, the deployment of a U of T-designed “intelligent transportation system” (ITS) could reduce wait times at intersections by 40 to 70 per cent. As a result, vehicle emissions would drop by as much as 30 per cent.”

“The training (simulation) environment shows us with good precision which intersections benefit the most and how much benefit to expect. This process helps prioritize investment and pick the best candidate intersections (or groups of intersections) to start with.”
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