Environmental Issues in
Urban Areas
Air Pollution
Main Causes
•
•
•
•
•
•
•
•
•
Vehicle exhausts
Industrial emissions
Emissions from power stations
Domestic Homes
Main Dangers
Nitrous oxides - In bright sunshine this undergoes a chemical change to form
a photochemical smog – and causes a serious health hazard to people,
plants and animals – good examples are
Ozone – This sensitises the body to irritants such as house dust or pollen –
affecting breathing
Carbon Monoxide – Caused by the incomplete combustion of fuel – effects
are headaches, fatigue, drowsiness and even death
Sulphur Dioxide – Produced from cars – it irritates eyes and aggravates
asthma and the respiratory system
Suspended Particles such as dust, cement, pollen, organic compounds and
petrol all affect the respiratory system
Case Study – Mexico
City
•
•
•




Reputed to be the worst
polluted city in world
Caused by Industrial, car and
the choking dust blown across
the city as well as mountains
that surround it
Plans to reduce pollution
Build a new underground
system
To develop bus transport but
lack of money is a problem
Introducing ‘the no drive today
policy which bans certain cars
being used
How successful? & Why?
Not really due to the number of
vehicles increasing and
enforcement is difficult
Solutions in other Areas
•
•
•
•
•
1.
2.
3.
Catalytic Converters
Lead Free Petrol
Sulphur free fuels
All the strategies for reducing
transport in cities including
congestion charging, Park and
Ride, Bus Lanes, etc
Develop cleaner transport
Electric Cars
LPG powered cars/dual use
e.g. Bristol Buses
Tax cars with high emissions
Answer Q1, 2 & 3 page 250
How can the strategies vary
between MEDC’s & LEDC’s
Give reasons for your
answer
Water Pollution
In MEDC’s – Britain
•
•
•
•




In England & Wales in 1990, 89% of rivers and canals were of good
water quality
In 1991 there were 30,000 reported pollution incidents
Main Causes
Sewage disposal – Most sent to treatment works where waste
products are removed – the effluent left should comprise of 95%
waste water and is discharged into rivers. Also 25% of country still
not served by sewage treatment works
Agricultural run-off – Farm waste and slurry effluent are normally
spread on farmland but due to heavy rain and accidents can lead to
them reaching a river.
Undiluted farm slurry is 100 times more polluting than raw sewage
Silage effluent is 200 times more polluting
Both use up large amounts of oxygen to break them down and
results in damage to plants & animals
Fertiliser-nitrates resulting in eutrophication
Water Pollution - Causes
•
•
•
Industrial Discharge – Some Industrial waste is discharged directly
into the river – with some being very harmful especially in the case of
chemicals – see video of Rhine for information.
Power Stations – Many power stations extract water for cooling
purposes before returning it to the river. Although the water is not
polluted, as it is considerably warmer than before it contains much less
oxygen and therefore harmful to river life.
Landfill Sites – Pollutants from waste landfill sites can leach slowly
into the rivers
Water Pollution in LEDC’s
Causes
1.
2.
3.
4.
5.
6.
Answer Question 1 page 253
Using page 250 outline the main causes of water pollution in LEDC’s –
how does this differ to MEDC’s
Case Study – The Ganges
Read the information on The Ganges from the separate sheet & page
253
Outline the main causes of pollution in the Ganges.
What is the GAP and how is it trying to improve water quality in the
Ganges.