DR. SHAHARUDDIN MOHD SHAM
DEPARTMENT OF ENVIRONMENTAL AND OCCUPATIONAL HEALTH
FACULTY OF MEDICINE AND HEALTH SCIENCES, UPM
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Geographical distribution of people in rural
areas, towns and cities significantly influences
the social, environmental and economic aspects
of population growth.
Example: In 1600s, the majority of the North
American population consisted of farmers in
rural areas. Today, approximately 25% of
people in the USA are involved in agriculture,
and the other 75% live in cities.
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Urbanization – process of which
people increasingly move from rural
areas to densely populated cities
What qualifies as an urban area?
Denmark – 250 people
 Greece – 10,000 people
 USA – 2,500 people
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Rural
Urban
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Important distinction between
rural and urban areas
 Rural
areas – have occupations that
involve harvesting natural
resources such as fishing, logging
and farming
 Urban areas – most have jobs that
are not directly connected with
natural resources
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Urban areas are more heterogeneous with
respect to race, ethnicity, religion and
socioeconomic status compared to populations
in rural areas
People in urban areas tend to be younger than
in the surrounding countryside. This is caused
by influx of many young adults from rural
areas.
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Urban and rural areas often have different
proportions of males and females
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Cities in developing countries tend to have more
males
Example: In African cities, males migrate to the cities
in search of employment, while females remain in
the country and tend the farms and their children
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Cities in highly developed countries often have a
higher ratio of females to males
Example: Women in rural areas often have little
chance of employment after graduating from high
school, so they move to urban areas
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The ecosystem approach is used to better
understand how cities function and how they
change overtime.
4 variables in urban trends and patterns –
POET
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Population
Organization
Environment
Technology
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Population
Refers to the number of people (birth,
death, immigration and emigration)
and the composition of the city by age,
sex and ethnicity
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Organization
Refers to the social structure of the city,
including its economic policies, method
of government and social hierarchy
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Environment
Refers to both the natural environment
such as location of the city by the river
or in the desert, and also the city’s
physical infrastructure, including
roads, bridges and buildings.
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It also includes changes to the natural
environment that are caused by
humans, such as water and air
pollution
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Technology
Refers to human inventions that directly
affect the urban environment.
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Example: aqueducts used to carry water
long distances to cities in arid
environments, and air-conditioning,
which allows people to live in comfort in
hot, humid cities.
The four variables (POET) do not function
independently, they are interrelated, often
in complex ways.
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Growing urban areas affect land-use pattern
and destroy or fragment wildlife habitat by
urban sprawl that encroaches into former
forest, wetlands, deserts or agricultural land in
rural areas
Example: Chicago, Boston and New Orleans in
the USA are former wetlands.
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Chicago
Boston
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New Orleans
before and after
Katrina (2005)
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Commuting from suburban areas to
city centres is a necessity for workers
living in large urban areas, and since
development is so spread out,
automobiles has become a important
tool to accomplish everyday chores.
This heavy dependence on motor
vehicles increases air pollution and
causes other environmental
problems.
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Water flow in cities are affected by covering
of rainfall-absorbing soil with buildings and
paved roads. It is polluted with organic
wastes, motor oil, lawn fertilizers and heavy
metals.
This water (called urban runoff) is cleaned up
in sewage treatment plants before being
discharged into nearby waterways.
However, high levels of precipitation can
overwhelm the treatment plants and result
in the release of untreated urban runoff.
This contaminates water far beyond the
boundaries of the city
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High density of automobiles, factories and
commercial enterprises in urban areas causes a
build-up of air-borne emissions, such as
particulate matter (dust), sulfur oxides, carbon
oxides, nitrogen oxides and volatile organic
compounds (VOC).
Urban areas in developing nations have the
worst air pollution in the world.
Example: In Mexico City, the air is so polluted
that schoolchildren are not allowed to play
outside during much of the school year.
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Mexico City
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Urban Heat Island
 Caused by the heat released by
human activities which is retained
by paved streets and buildings and
slowly released into the
atmosphere.
 Cities
are also warmer than the
surrounding countryside.
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A well-planned city actually benefits the
environment by reducing pollution and preserving
rural areas.
Compact development
Cities are designed so that tall, multiple unit residential
areas are close to shopping and jobs, all of which are
connected by public transport.
 Fewer parking lots and highways are needed, so there are
more room for parks, open space, housing and
businesses.
 Compact development makes a city more livable, and
more people may want to live there.
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Nagoya in Japan. This is a compact city with small businesses occupying
the lower floors of its average 10-15 level commercial + residential buildings
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47% of the world’s population currently lives
in urban areas. Before 2010, it will increase to
more than 50%.
Percentage of people living in cities compared
to rural settings currently is greater in highly
developed countries (75%) than is developing
countries (40%).
Most urban growth in the world is occurring in
developing countries whereas highly
developed countries are experiencing little
urban growth.
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Although proportionately more people
still live in rural areas in developing
countries, urbanization has been
increasing rapidly.
UN Data: 400 cities worldwide has a
population of more than 1 million; 284 are
in developing countries.
1950: only 3 of the 10 largest cities in the
world were in developing countries; In
2000: 7 of the largest cities were in
developing countries.
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The faster pace of urban growth in developing countries has
outstripped the limited capacity of many cities to provide
basic services. It has also overwhelmed their economic
growth.
The challenges faced are:
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Substandard housing (slums and squatter areas)
Poverty
Exceptionally high unemployment
Heavy pollution
Inadequate or nonexistent water, sewage and waste disposal
Strain schools, medical and transportation systems
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Homelessness – shared by cities in both
developed and developing countries.
This problem is more pronounced in the
cities of developing countries.
In the USA, there are 300,000 to 500,000
homeless people on any given night.
In Calcutta, India, perhaps 250,000
homeless people sleep in the streets each
night.
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Poverty
Crime
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Example: Understanding crime in urban and rural
areas (handout)
Potential epidemics in densely populated cities
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Example: risk of urban yellow fever outbreaks in
Africa (handout)
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1.
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5.
What is urbanization?
What is the urbanization trend today in largely
rural nations?
What are some of the problems brought on by
rapid urban growth in developing countries?
Which countries are the most urbanized?
The least urbanized countries?
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