The Main Question for Urban Planners to Resolve- Sprawl or Densification?

Although an important factor, there is a complex relationship between urban densities and car use. (Photo credit: Wikipedia)

Density: Drivers, Dividends and Debates (32 page pdf, Greg Clark, Emily Moir, Urban Land Institute, Jun. 23, 2015) Also discussed here: Density: Drivers, Dividends and Debates (Catherine Anderson , Urban Land Institute, Jun. 23, 2015) 

 A compact city tends to be more environmentally sustainable and has generally cleaner air than one that is spread out with emphasis on making it easier for people to drive to the centre of town with emphasis on roads wherever it allows them to drive more quickly. Today we review a research paper that examines the meaning(s) of urban density, explores the many myths about sprawl and intensification and suggests better designed and more sustainable cities for the future. Cities are categorized in terms of the density of their urban core, inner city and suburbs as Low-High-Low (typical of Europe), Low-Low-Low (typical of sprawled cities in USA/Canada/Australia), Low-Low-High (Toronto, Oslo), Medium-High- High (developing world cities). High density cities enjoy a number of advantages over low density ones, including walkability, natural habitats and economic waste disposal but fears of lower livability, traffic congestion and noise/pollution in high density cities need to be mitigated. Oslo and Toronto are seen as large cities where the balance is more nearly found. 

Key Quotes:
“54 percent of the world’s population, some 3.9 billion people, live in urbanised areas. By 2050 the urban proportion of the population is projected to grow by 2.5 billion, reaching 66 percent of the total
“ how to deliver successful densification is not so obvious and is one of the most important topics of this urban decade. Good density will mark out the next generation of winning cities”
“The Downtown and Central Waterfront area [of Toronto] is the key area for both residential and commercial development, with close to 40% of approved new developments in the city. … Toronto had more high rise buildings under construction than any other city in North America from 2012 to 2014.”
“The key combination is density with place-making and infrastructure. If you have both you get a really successful city like London. If you have density without place-making you get a different kind of city.”
“Vienna and Paris stand out as higher density cities which perform strongly on the positive benchmarks ….Mexico City on the other hand is a high density city that is the worst performer on both ‘good’ and ‘bad’ density indicators. …. Although less dense overall than the majority of the case study cities, Toronto is particularly successful in minimising the negative effects of density. “
some typologies:

• Low-High-Low cities:are cities which are characterised by high density cores, but much lower density …European cities
• Low-Low-Low cities:are those cities with expansive suburbs and high levels of car dependence, as well as spacious downtown zones. Many North American cities..
• Low-Low-High cities:are those cities which have made conscious efforts to densify particular neighbourhoods or districts…Toronto and Oslo..
• Medium-High-High cities:are both sprawling and dense, with crowded informal housing on the peripheries and particular pockets of very high density, around transit hubs for example… developing world cities..”

“Environmental aspects:

• Energy consumption is reduced in compact cities.
• denser cities are more walkable, and can provide more viable public transport options.
• More compact urban forms have smaller physical footprints, preserving greenfield sites and natural habitats.
• Waste disposal and management services can be more viable and economical to construct and operate at high density”

“liveability concerns (fear of overcrowding, noise and pollution, traffic, lack of green space) .. most important contemporary reasons for resistance to density, ahead of social concerns (crime, segregation) or economic concerns”

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"Avoid, Shift, Improve" - Decarbonizing Quebec’s Transportation Sector

Energy policy 2016-2025 - Decarbonization of Road Transport (73 page pdf, Gouvernement du Québec Ministère de l’Énergie et des Ressources naturelles, 2015)

Today we review a background paper prepared by the Quebec Ministry of Energy and Natural Resources, outlining plans to reduce the emission of carbon emissions by the transportation sector in that province, 76% of which comes from road transport. Recognizing that 99% of the province’s energy is produced from renewable energy sources, principally hydro, the main emphasis of the Avoid, Shift, and Improve plan, is on reducing travel in privately owned vehicles, shifting to use of a 95% electrified public transit and improving engine efficiency and increase the use of non carbon biofuels, propane and natural gas. Encouragement to convert to hybrid or totally electric vehicles (18% or 1.2 million by 2020 from under 6,000 today), and make more use of shared cars with an eye toward driverless or autonomous cars in the future that make fewer demands on the road infrastructure.

   

Key Quotes :

“in 2011, the road, air, maritime, rail and off-highway transportation sector generated 36 MT of CO2 equivalent, i.e. 44% of total emissions in Québec. Road transport alone accounted for 76% of transportation-related GHG emissions, i.e. 34% of total emissions.”

“The 2011-2020 Action Plan for Electric Vehicles…proposes ambitious targets including sales of hybrid or electric vehicles equivalent to 25% of annual new light-duty vehicle sales by 2020…in 2030, 1.2 million electric vehicles will operate on Québec roads (18% of registered light-duty vehicles), which will reduce gasoline consumption by 1.5 billion litres and GHG emissions by 3.5 million tonnes.” “the 158 000 heavy-duty road vehicles—including buses—represent a small proportion of the vehicles registered in Québec (roughly 2.6%), they consume nearly one-third of the petroleum products used for road transportation, mainly diesel. They account for one-third of GHG emissions and 80% of the particulate emissions attributable to the sector”

Avoid-Shift Improve Approach:

“Avoid This component comprises initiatives to avoid or reduce passenger travel and to shorten travel distances….  

Shift This component refers essentially to the transition from solitary use of a privately-owned motor vehicles to public transit or carpooling services..

 Improve 1) the enhancement of the energy efficiency of existing motor vehicles; 2) the use of alternative fuels with lower carbon dioxide footprints, in particular biofuels and natural gas; 3) the replacement or assistance of an internal combustion engine powered by a battery or a fuel cell (hydrogen).”

“nearly twice as many Quebecers appear to rely on bicycles for recreational purposes or travel than the North American average…the number of bicycle trips rose by 33% in Montréal’s central neighbourhoods between 2008 and 2013.”

“Fully autonomous vehicles are being tested and certain of their features will soon be incorporated into mass-production vehicles. Google announced the launching, in December 2014, of its autonomous car ready for testing on North American roads starting in 2015. Moreover, numerous automakers such as Audi, Toyota, Nissan, General Motors and Mercedes-Benz are carrying out autonomous car projects.”

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How Does Traffic Related Air Pollution Affect Children's Health?

English: Southern end of the High Street, Keynsham, on a busy Saturday. (Photo credit: Wikipedia)

Blood Pressure and Same-Day Exposure to Air Pollution at School: Associations with Nano-Sized to Coarse PM in Children (6 page pdf, Nicky Pieters, Gudrun Koppen, Martine Van Poppel, Sofie De Prins, Bianca Cox, Evi Dons, Vera Nelen, Luc Int Panis, Michelle Plusquin, Greet Schoeters, and Tim S. Nawrot, Environmental Health Perspectives, Jul. 2015)

Today we review research into the links between short term exposure to particulate matter of various sizes and impacts on blood pressure of school-age children who are particularly vulnerable because their higher breathing rate, as well as their generally greater activity than older people. Results indicate a clear association with Ultra Fine Particulates (diameter 20-30 nm) and higher blood pressure. In addition, repeated exposure to particulates may result in long-term chronically elevated pressures, as well as a chronic increase in arterial stiffness in children due to traffic-related air pollution.

Key Quotes:

“Short-term elevation in particulate air pollution has been associated with an increased risk for acute myocardial infarction and stroke”

“this is the first study of differences in children’s blood pressure in association with different size fractions of PM on the same day.. "

“In this study, children’s systolic blood pressure was positively associated with ambient UFP[ultra-fine particulates] measured in their school’s playground on the same morning”

“children might be more sensitive to air pollution because of their relatively higher ventilation rate and metabolic turnover, as well as the fact that some of the organ systems including the immune system are still in development… greater physical activity, spending more time outdoors, and their closer proximity to traffic exhaust emission sources compared with adults, might add to their vulnerability towards hypertensive effects of airborne particles”

“particle size is a determining factor in the effectiveness of particulate pollutants to cause rapid changes in the blood pressure of 6- to 12-year-old children”

 “repeated particle-induced elevations in blood pressure also lead to repeated increases in arterial wall stress and may result in long-term chronically elevated pressures. Epidemiological evidence exists for a chronic increase in arterial stiffness in children due to traffic-related air pollution”

 “Due to specific characteristics (high surface area, particle number, metal and organic carbon content) of UFP[ultra-fine particulates], they may be transferred directly into the circulation and cause systemic inflammation and peripheral vascular oxidative stress resulting in reductions of nitric oxide, enhancing vasoconstriction and as such change blood pressure.”

"Children attending school on days with higher ultrafine particulate concentrations (diameter < 100 nm) had higher systolic blood pressure. This association was largely dependent on particle size and was not confounded by the PM2.5 mass concentration.”

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Links between Air Pollution and Premature Deaths in the Netherlands

Air Pollution and Mortality in Seven Million Adults: The Dutch Environmental Longitudinal Study (DUELS) (8 page pdf, Paul H. Fischer, Marten Marra, Caroline B. Ameling, Gerard Hoek, Rob Beelen, Kees de Hoogh, Oscar Breugelmans, Hanneke Kruize, Nicole A.H. Janssen, and Danny Houthuijs, Environmental Health Perspectives, Jul. 2015)

Today we review research into the links between mortality of the adult Dutch population and exposure to NO2 and PM10 that establishes a new basis for that country. Results indicate a higher general mortality association with PM10 than previously estimated and with NO2 for all mortality except circulatory disease.

   

Key Quotes:

 “In this large Dutch nationwide population cohort of > 7 million adults we observed positive significant associations between estimated long-term exposure to air pollution (PM10 and NO2) at the home address and nonaccidental, circulatory disease, respiratory disease, and lung cancer mortality”

“the median PM10 concentration was 29 μg/m3 [5th–95th percentile, 24 μg/m3–32 μg/m3; interquartile range (IQR) = 2.4]; the median NO2 concentration was 31 μg/m3 (5th–95th percentile, 19 μg/m3–44 μg/m3; IQR = 10.0 μg/m3). We estimated HRs per 10-μg/m3 increase in the pollutant concentration..the range (and IQR) in NO2 concentrations is larger than the range in PM10 concentrations, because NO2 is more influenced by local (traffic) emissions than PM10, which is more affected by long-range transport.”

“we found particulate matter to be associated with all outcome measures that we have analyzed. Our relative risk estimate for PM10 on total mortality is higher than the relative risk estimate from a recent published study based on 19 European cohorts”

“For NO2 we found statistically significant associations with all outcomes except for circulatory disease mortality”

 “Our estimates for lung cancer mortality for PM10 and NO2 are higher than those published recently in the national cohorts”

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How do Fireworks Affect Local Air Quality?

Effects of Independence Day fireworks on atmospheric concentrations of fine particulate matter in the United States (7 page pdf, Dian J. Seidel, Abigail N. Birnbaum, Atmospheric Environment, May 30, 2015)

Also discussed here: July 4 fireworks spark astonishing spike in air pollution, NOAA study finds (Jason Samenow, Washington Post, Jun. 30, 2015)

Today we review a nation-wide assessment of the impact of fireworks on local air quality in the USA. Results indicate tht the particulates emitted during these displays increased particulate pollution by 42% on average, although individual cities had increases of 400% temporarily and other venues such as the International Fireworks Competition in Montreal and New Years Eve in Germany showed increases of 40 to 50 times more. As the particulate emissions from these eruptions last only for a few hours, the higher pollution levels are not counted in either the national air quality regulations (such as National Ambient Air Quality Standards for PM2.5 in the USA or European Union PM10 air quality standard). Clearly short term air quality forecasts could be improved using the results from this study. In addition, spectators would be well advised to stay upwind from the fireworks to avoid polluted air and the health impacts that may result from breathing it.

   

Key Quotes:

“Every July 4, the 14,000-plus dazzling fireworks displays across the nation have a toxic effect on our atmosphere…they temporarily increase particulate pollution by an average of 42 percent. "

“PM2.5 concentrations peaked around 9-10 p.m. on July 4 at more than twice their average concentration before dropping back to background levels by around noon on July 5.”

“[in Washington DC] Between about 8 and 10 p.m., PM2.5 levels surged by over 400 percent compared to average before gradually returning to background levels the next day” “At one site adjacent to fireworks, hourly PM2.5 levels climb to ~500 mg/m3, and 24-hr average concentrations increase by 48 mg/m3 (370%).”

“Increase in PM2.5 by up to a factor of 50 within the fireworks plume and within 2 km of the launch site during the 2007 Montreal International Fireworks Competition” “Increase in sub-micron particle mass concentration by a factor of 10 or greater for about an hour following the 2005 New Year's celebration fireworks in Mainz, Germany, and a daily average concentration on January 1 exceeding the European Union PM10 air quality standard of 50 mg/m3”

 “Designated exceptional events are not included in determining compliance. Some fireworks events have been allowed exceptional event Designation..While the EPA does not regulate fireworks, the agency does recommend that people who are considered sensitive to particle pollution try to limit their exposure by watching fireworks from upwind – or as far away as possible,”

“Current air quality prediction efforts in the US address PM2.5, but the national prediction models do not currently include fireworks as source of particulate emissions … although local forecasters may account for fireworks effects in communications with the public.”

Short-Term Impacts on Health from Multiple Pollutants in an Urban Environment

Exploring associations between multipollutant day types and asthma morbidity: epidemiologic applications of self-organizing map ambient air quality classifications (13 page pdf, John L. Pearce, Lance A. Waller, James A. Mulholland, Stefanie E. Sarnat, Matthew J. Strickland, Howard H. Chang and Paige E. Tolbert, Environmental Health, Jun. 23, 2015)

Today we review research conducted in Atlanta on the relationship between exposure to groups of up to 10 pollutants and the health impacts brought on by asthma. Results indicate the same high relationship between adverse health impacts and higher levels of pollution that has been seen in examining the impacts of a single pollutant. When groups of pollutants were examined, the highest asthma morbidity was seen on days that were warm and dry with emissions from vehicles one of the three highest classes. This shows the value of looking at the combined impacts of several pollutants.  

Key Quotes:

“extreme NO3 days that occurred 7 % of the time under cool, wet, stable conditions. This agrees well with understanding of how low temperatures and high relative humidity contribute to the formation of nitrate rich aerosols in Atlanta”

“11 % of days … were dominated by well-above average to extreme conditions for several primary pollutants such as CO, NO2, NOX, EC, and OC. Consistent with these relatively cold dirty days are the high pressure, low wind speeds, and low humidity conditions suggestive of poor atmospheric mixing and potential inversions”

“high ratios of OC/EC .. are indicative of days dominated by mobile source emissions from gasoline..however, .. is far less frequent (3.3 % of days) and highlights days when several pollutants are two to three times higher than average – a scenario we might a priori describe as the most hazardous air quality scenario in our study."

“We found significant associations of increased asthma morbidity for (1) days that were most warm, with low winds and humidity .. and very high levels for secondary pollutants (O3 and ammonium sulfates); (2) days that were the driest and most stable .. with very high primary pollutants from vehicles (CO, NOx, EC, and OC), and (3) days that were generally warm, stable and dry .. with elevated levels for both primary and secondary pollutants.”

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