Urban+Stress

= Urban Microclimate =

Examine the effects of structures and human activity on urban microclimates, including the urban heat island effect and air pollution.
What are microclimates? A microclimate is the distinctive climate of a small-scale area, such as a garden, park, valley or part of a city. The weather variables in a microclimate, such as temperature, rainfall, wind or humidity, may be both subtly different due to Albedo, Vegetation, Altitude, Slope / Aspect, Moisture content

Urban microclimates These are perhaps the most complex of all microclimates. Urban and rural environments differ substantially in their micro-climate. These climatic differences are primarily caused by the alteration of the Earth's surface by human construction the release of artificially created energy into the environment.

Defined as a distinctive climate associated with a large urban area. It is characterised by the occurrence of significantly higher temperature than the rural surroundings. This human induced climatic modification is often referred to as Urban Heat Island.

Urban Heat Island (Higher Temperature) In general, the temperatures are highest in the central areas and gradually decline towards the suburbs. In some cities, a temperature cliff occurs on the edge of town - this can be clearly seen on the heat profile below for Chester (where?) Chandler (1965) found that, under clear skies and light winds, temperatures in central London during the spring reached a minimum of 11 °C, whereas in the suburbs they dropped to 5 °C.

The term urban heat island is used to describe the dome of warm air that frequently builds up over towns and cities.

The formation of a heat island is the result of the interaction of the following factors. (a) The release (and reflection) of heat from buildings.

(b) The canyon structure that tall buildings create enhances the warming. During the day, solar energy is trapped by multiple reflections off the buildings while the infrared heat losses are reduced by absorption At night, there is more heat to release by terrestrial radiation. However, much of the heat is trapped. Only very little is filtered out of the city. This is because the vertical surfaces of building absorbs, reflect and re-radiate heat among themselves and to the ground. The low and few buildings as wooden and thatched materials allow more reflection and re-radiation of heat. This keeps the rural areas cool.

(c) The thermal properties of buildings add heat to the air by conduction. Tar, asphalt, brick and concrete are better conductors of heat than the vegetation of the rural area. These surfaces absorb and store greater quantities of heat than the softer vegetated surfaces of rural areas. These surfaces thus radiate sensible heat into the lower atmosphere.

(d) Concentration of pollutants and impurities in the air The emission of hygroscopic pollutants from cars and heavy industry - these act as condensation nuclei, leading to the formation of cloud and smog, which can trap radiation. In some cases, a pollution dome can also build up. The presence of atmospheric pollutants / impurities in cities give rise to a stronger green house effect or blanketing effect. These pollutants absorb long wave radiation from the earth’s surface and re-radiate it downward. Recent research on London's heat island has shown that the pollution domes can also filter incoming solar radiation, thereby reducing the build up of heat during the day. At night, the dome may trap some of the heat from the day, so these domes might be reducing the sharp differences between urban and rural areas.

(e) Sensible ‘waste’ heat by human activities such as combustion engine, heating and cooling systems of buildings etc.

(f) The relative absence of water in urban areas means that less energy is used for evapotranspiration and more is available to heat the lower atmosphere.

(g) The absence of strong winds to both disperse the heat and bring in cooler air from rural and suburban areas. Indeed, urban heat islands are often most clearly defined on calm summer evenings, often under blocking anticyclones.

2. Wind Local changes in pattern and speed of wind as air is funnelled between tall buildings and along narrow streets. Tall buildings within city centre act as wind breaks or wind canyons. Air circulation is broken and turbulence occurs in vicinity of tall city towers. Tall buildings can significantly disturb airflows over urban areas, and even a building 100 metres or so high can deflect and slow down the faster upper-atmosphere winds. The net result is that urban areas, in general, are less windy than surrounding rural areas. However, the 'office quarter' of larger conurbations can be windier, with quite marked gusts. This is the result of the increased surface roughness that the urban skyline creates, leading to strong vortices and eddies. In some cases, these faster, turbulent winds are funnelled in-between buildings, producing a funnel effect, swirling up litter and making walking along the pavements quite difficult. Wind velocities tend to eliminate heat island effect. The larger the city, the stronger the winds are necessary to dissipate heat island effect. Yet strong winds are hard to come by in the cities as tall buildings act as wind breaks.

Other types of environmental and social stress
= Examine the other symptoms of urban stress including congestion, overcrowding and noise, depletion of green space, waste overburden, poor quality housing, social deprivation, crime and inequality. =

** Overcrowding **
Urban growth often take place without sufficient investment in transport infrastructure. When this happens people are subjected to unnecessary stress as a result of more time spent travelling, delays and overcrowded public transport systems. Overloaded transport systems result in a number of negative effects:
 * Longer journey times, either as the direct result of delays or the need to allow extra time to cater for unpredictability. Often the extra time is wasted because it cannot be used productively.
 * Increasingly uncomfortable and unsafe travelling conditions for those using public transport systems.
 * Arriving late for work, meetings, etc, thereby wasting time both for the traveller and others.
 * Wasted fuel because vehicles are unable to operate at optimum speeds
 * Consequent additional wear and tear on vehicles and higher levels of air pollution.
 * Stressed and frustrated travellers, which may lead to road rage and reduced mental and physical health.
 * Traffic congestion delays to emergency vehicles.
 * Diversion of traffic through residential and recreational areas due to spill-over of traffic from congested routes, with consequent loss of amenity, local noise, air pollution and greater risk of accidents.

** Green Space **
Green spaces” are the trees and grass and shrubs in yards, parks, medians, anywhere intermingled throughout the built environment. Green space is any piece of land covered with vegetation. Usually refers to parks, golf courses, sports fields and other open land within the built‐ up area, whether publicly accessible or not. Trees, grass and other green vegetation provide wildlife habitat, prevent soil erosion, absorb air pollutants, and lower surface temperatures. Lack of green spaces leads to higher air temperatures and more ground level ozone, with fewer trees and plants to clean the air and provide oxygen. Without soil to receive the rainfall and filter the water, sewers become overloaded, causing neighborhood flooding problems as well as polluted water problems which is harmful to aquatic ecosystems. Green space has a positive impact on mental health. People living in areas with green spaces are less likely to have anxiety disorders or depression, and they are more likely to be physically active, which leads to reductions in respiratory diseases such as asthma, COPD, and upper respiratory infections. Some studies suggest that green spaces reduce common health conditions including cardiovascular disease, diabetes, and cancer. Use of green space for bike trails and recreation may lead to reduced use of automobiles and transportation systems, thus reducing the use of fossil fuels and energy expenses. Additional tree and vegetative growth provides shade and lowers urban temperatures reducing the demand for air ‐ conditioning and energy costs. **Solutions ** Individuals: Utilize parks and current green space to improve personal health, become physically active, and improve personal well being. Start and participate in community ‐ shared gardens. Share your knowledge and educate your neighbors, friends, and family on the benefits of green space. Advocate for more public green spaces. Communities: <span style="font-family: 'Times New Roman','serif'; font-size: 12pt;">Attend city council meetings that deal with city planning, public transportation, energy, air, and water quality to learn more. <span style="font-family: 'Times New Roman','serif'; font-size: 12pt;">Promote sustainable, environmentally beneficial landscape practices <span style="font-family: 'Times New Roman','serif'; font-size: 12pt;">Policies: <span style="font-family: 'Times New Roman','serif'; font-size: 12pt;">Implement more regulations and changes in city planning that incorporate more green space and natural environments into the design. Case Study Save or recreate? Lessons from Singapore on the value of green spaces Rachel Sullivan <span style="font-family: 'Times New Roman','serif'; font-size: 12pt;">Singapore – the world’s wealthiest nation by GDP per capita – has limited room to move when it comes to sustainable development.1 Its lack of land area (its total area is just 712 square kilometres), rivers, strong winds and geothermal energy, for example, restrict the city-state’s prospects for alternative energy sources.

<span style="font-family: 'Times New Roman','serif'; font-size: 12pt;">Recently, however, the tiny intensively urbanised island – whose official population has almost doubled in the past 20 years to 5.2 million – began its journey to becoming a ‘City in a Garden’. <span style="font-family: 'Times New Roman','serif'; font-size: 12pt;">This new policy initiative is expected not only to cement its position as Asia’s most sustainable city, but to also pay dividends in terms of its liveability and boost its appeal to foreign business investment. <span style="font-family: 'Times New Roman','serif'; font-size: 12pt;">‘Our former Prime Minister Mr Lee Kuan Yew had the vision of making Singapore a Garden City in 1963,’ says Mr Poon Hong Yuen, CEO of Singapore’s National Parks Board. <span style="font-family: 'Times New Roman','serif'; font-size: 12pt;">‘It was a revolutionary concept in those days when “going green” was not fashionable. Yet Mr Lee and Singapore’s pioneers persisted in the vision because they believed it would mitigate against the harsh urban environment as Singapore developed, improve the quality of life for Singaporeans, and remind investors that Singapore was a place where things worked.’ <span style="font-family: 'Times New Roman','serif'; font-size: 12pt;">The conventional thinking is that the development of a country, and especially of a small city state, would take place at the expense of greenery and nature, he adds. ‘But even as Singapore’s population and economy grew, the green cover of Singapore, as measured from satellite images, actually grew significantly. <span style="font-family: 'Times New Roman','serif'; font-size: 12pt;">‘Today, our 1.4 million roadside trees form the backbone of our Garden City while parks and gardens take their place as key community spaces. <span style="font-family: 'Times New Roman','serif'; font-size: 12pt;">‘One of the four nature reserves in Singapore, the Bukit Timah Nature Reserve, is also one of two primary rainforests in the world located within city limits, the other being Rio De Janeiro.’ <span style="font-family: 'Times New Roman','serif'; font-size: 12pt;">Mr Poon says the City in a Garden vision will help strengthen Singapore’s brand as a distinctive, liveable city. <span style="font-family: 'Times New Roman','serif'; font-size: 12pt;">‘There are three key pillars of the City in a Garden vision. First is pervasive greenery. We have greenery everywhere, from the ground to the facade and rooftops of buildings. Second is infusing biodiversity into our urban landscapes. The third [pillar] is community involvement – active participation, ownership and pride among the community will sustain the City in a Garden vision.’ <span style="font-family: 'Times New Roman','serif'; font-size: 12pt;">As well as developing the world-class Gardens by the Bay (see box below) and enhancing selected regional parks, the City is also developing more green corridors or ‘park connectors’, making use of drainage and road reserves to link housing estates to parks and nature sites. <span style="font-family: 'Times New Roman','serif'; font-size: 12pt;">‘We have about 220 km of park connectors now and aim to extend the network to 300 km by 2015,’ Mr Poon says. ’As an extension of this park connector network, we are also planning the round island route, a 150 km green recreational corridor that goes around Singapore.’ <span style="font-family: 'Times New Roman','serif'; font-size: 12pt;">Most the city’s population live in high-rise apartments. Selling points in real estate ads aimed at attracting buyers to new residential developments include proximity to a park, or the inclusion of rooftop or vertical greenery. <span style="font-family: 'Times New Roman','serif'; font-size: 12pt;">‘The quantifiable benefit is land value appreciation, but there is also the unquantifiable benefit of living near rich biodiversity, which can result in improved physical and mental health,’ Mr Poon says. <span style="font-family: 'Times New Roman','serif'; font-size: 12pt;">How does he account for that fact that, in the past, the Singapore government has turned green spaces into air-conditioned shopping malls and high-rise developments? In Mr Poon’s view, the government has successfully balanced development with conservation of Singapore’s rich biodiversity. <span style="font-family: 'Times New Roman','serif'; font-size: 12pt;">‘Tiny Singapore is home to 364 species of birds, about 75 per cent of the number of species found in France; 305 species of butterflies, or five times as many species as can be found in the United Kingdom; and 255 species of hard corals, more than a third of the world total and 70 per cent of [the number found] in the Great Barrier Reef,’ he says. –
 * Source: http://www.ecosmagazine.com/?paper=EC13052#sthash.QXUTclpE.dpuf **

Air pollution by unpleasant odours and wind-carried suspensions is obvious in areas located nearby urban waste landfills, since these are currently run in complete ignorance of practices such as cell operation and inert matter lagging.
 * Waste Overburden **

The leakage on the slopes of landfills situated nearby surface water bodies adds to the pollution of such waters by organic substances and suspensions. The urban waste landfills that are not waterproof often represent sources of groundwater pollution by nitrates and nitrites, as well as other pollutants. Landfill exfiltration and water leakage on the slopes affect adversely the quality of the adjoining soils, which brings along consequential effects to their utilization. Waste, and industrial waste in particular, represents a health hazard, due to its content in toxic substances such as heavy metals (lead, cadmium), pesticides, solvents, and used oils.

The problems faced by waste management activities in urban areas can be summarized as follows:
 * storage in open grounds is the most used method to remove waste;
 * waste landfills are improperly designed from an environmental protection point of view, thus allowing for water and soil pollution in those areas;
 * currently waste landfills, and urban landfills in particular, are not operated in a sound manner: waste layers are not compacted and they are not lagged with inert matter periodically, so as to prevent fire and unpleasant odours; there is no strict control of the quality and quantity of waste that is dumped on the landfill; there are no facilities to assess the amount of biogas produced; the main and secondary roads used by the waste carrier vehicles are not maintained, the transport vehicles are not washed up when departing from the landfill; many landfills are not even fenced in, and do not feature an appropriate point of entry, nor warning signs.
 * household waste is not collected in a selective manner; the mixed waste is dumped on the landfills as is, thus a great part of their potential usefulness (paper, glass, metal, plastic matter) is lost.

**Crime and Inequality**
For many people, especially those who belong to the middle class and elite and to government circles, it is the urban poor who are responsible for violence and crime in the cities. This is a prejudice that has often hindered any attempt to get to the heart of the problem of either poverty or crime and violence, in our cities. It is true that urban poverty has grown in much of the world over the last two decades and in this period there has also been a substantial increase in crime and violence focused primarily in the cities.

The key issue is that poverty reflects the inability of an individual, household or community to satisfy certain basic minimum needs'. The __assumption follows is that due to frustration and insecurity and the presence of absolute and relative poverty, the urban poor are forced to resort to crime and violence.__ While there is some evidence which links urban poverty and unemployment to crime and violence, it would be too simplistic to make a direct correlation between poverty, violence and crime in cities. Moreover, the fact that slums and squatter areas have a higher incidence of crime and violence than more well-to-do areas in the city, also does not necessarily imply that it is the urban poor who actually partake in that violence or crime. The presence of organised gangs and mafias in all cities, often controlled by people who are neither poor nor reside in slums, suggests that the __urban poor are often manipulated, due perhaps to their vulnerability, and become either victims or party to crime.__

The distribution of crime in the city

 * Nature of Crime || Perpetrators || Victims || Causes || Location and Impact ||
 * Petty crime, theft || Wide variety of individuals, probably from low and middle income levels || Same as perpetrators || Opportunity, necessity || Localised ||
 * Domestic violence || Men || Female partners || Culture, frustration, tradition || Household ||
 * Violent Crime: murder, assault, mugging || Men between age 15-35 || Same as perpetrators || Enmity, power, petty crime gone undone || Household, neighbourhood ||
 * Armed robbery, household kidnapping || Men, often as part of a gang || Upper and middle class households || Ransom, enmity, high financial returns || Localised, neighbourhood ||
 * Political violence || Organised or unorganised groups/parties || State, other groups || Numerous || Local, city-wide ||
 * Mob/gang neighbourhood violence || Mafia, gangs || Other gangs, groups, individuals || Terrain, power, politics || Localised ||
 * Crimes against property || Mafia, state, municipality, individuals, groups || State/private land and property, other gangs/groups || Need for land, housing or speculation || Localised, neighbourhood ||
 * Drug trafficking || Organised groups, middlemen, police, state || Individuals across social classes || Large financial gains || Neighbourhood, city, ||

Housing segregation is often defined as a spatial separation in a built environment or area of members of two or more categories, where the members within each category share an exclusive feature.
 * Inequality **

1. Types of Social Segregation Social status - Interpreted in terms of educational qualification, occupation and income Social Class - differentiation also involves culture and value Class structure: formal categorisation of in a society at a given time
 * Based on the positions people held within the division of labour and framework of economic organisation
 * E.g. middle class people are those working as professionals and middle level management
 * Lower class people are those working as manual labours, hawkers and street vendors

2. Main factors that lead to Segregation in terms of Social Status Education: Quality and type of schools
 * An element of social reproduction, providing skills and academic status for maintenance or upgrading of social class
 * E.g. in the USA, good schools are found in localities in affluent neighbourhoods where people have the resources to fund quality education.

Marriage
 * The nature conservatism of parents tends to foster marriage within their perceived social group, which tend to locate within homogenous communities.

Stereotyping
 * Limited interaction lead to people creating a model of another group base on incomplete information
 * It tend to exaggerate inter-group differences, thus increasing perceived social distance, re-enforcing spatial segregation

Household types
 * Household types include, nuclear family unit, extended family unit, single person household, single parent household, childless, gay couples, etc
 * Members of similar household type will have common attributes and needs
 * Similarity in residential needs and preference lead to congregation, thus spatial segregation between different groups

Ethnicity
 * Covers any group characterised by race, religion, nationality and culture
 * Degree of segregation depends on the process of assimilation of new migrant to the host society