ETV “Secondary Level Environmental Education Series” Programme
Air Pollution
Teachers' Notes
Target Audience
S1 – S7
Duration
20 minutes
Production Aim
This programme is suitable for use in science subjects including biology/human
biology, liberal studies and environmental education lessons.
Key Points
1. An introduction to the source of air pollution and composition
of the pollutants ;
2. An explanation to the effect of air pollution on health ;
3. An introduction to Hong Kong’s strategy for tackling air
pollution ;
4. An introduction to the operation of air pollution monitoring
system in Hong Kong.
Content Outline
This programme is divisible into 5 parts as follows:
1.
Air pollution culprit
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Introduce the use of portable digital calibrator and gas detector tubes to test
for gas pollutants. X-ray screen machine may be used to analyze the
suspended particulates in solid pollutants.
Major gaseous pollutants in the air:
Sulphur dioxide is produced when mineral fuels are burnt or when
substances containing sulphur are processed in power plants or boilers. It’s
also present in the exhaust emissions of road vehicles.
Nitrogen oxides are oxides of nitrogen. They include nitrogen monoxide
and nitrogen dioxide. They are produced during high temperature
combustion in power generators and by running car engines.
Carbon monoxide is produced when carbon or fuel is not burnt completely.
It is also produced by some industrial procedures. Vehicle exhaust fumes are
major sources of carbon monoxide.
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2.
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Ozone is another kind of pollutant gas, (but this one isn’t produced by
industrial procedures and isn’t found in vehicles’ exhaust fumes. Rather,) it
is formed when nitrogen oxides react with certain volatile organic
compounds under the ultra-violet rays of sunlight.
Suspended particulates come from diesel car engines, construction works
and certain industrial procedures. Some occur in nature. Suspended
particulates contain various chemical particles, inorganic fibres, minute
particles of metals like lead, and various organic matters.
Hazards of air pollution
Sulphur dioxide is a colourless gas.
It is odourless at low concentrations and
pungent at high concentrations. Exposure to an environment with a high
concentration of sulphur dioxide can damage the respiratory system. In people
suffering from bronchial allergy or bronchitis, it can lead to shortness of breath,
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difficulty in breathing, or coughing.
Nitrogen monoxide reacts with haemoglobin in the blood to form a stable
compound, which obstructs the transportation of oxygen to body parts by red
blood cells. Nitrogen dioxide can also irritate the lungs and lower the respiratory
system’s resistance to infection, rendering the body prone to influenza. The effect
is particularly strong in children; if serious enough it can obstruct lung growth.
Carbon monoxide is colourless and odourless. carbon monoxide can combine
with haemoglobin to obstruct the transportation of oxygen around the body.
Long-term exposure to carbon monoxide can lead to considerable impairment,
including damage to learning and working ability, as well as to brain function.
Exposure to high concentrations of carbon monoxide can even be fatal.
Ozone toxicity is cumulative. The higher the concentration and the more
vigorous the activity during contact, the greater its effect will be. Ozone irritates
the mucous linings of the nose, throat and bronchi. It will attack the respiratory
system and damage pulmonary function.
When suspended particulates enter our lungs, they are collected deep inside. This
causes harm to our health, including respiratory problems and even long-term
damage to lung tissue.
3.
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Air Pollution Index
To enable the public to understand the air pollution situation, Environmental
Protection Department will announce the air pollution index to the public on an
hourly basis. There is also daily forecast of the index for the following day.
EPD has set up more than 10 fixed monitoring stations across the territory to
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monitor the air quality. The programme shows how the monitoring station works
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4.
to measure the concentration of suspended particulates by using a high volume
sampler as well as to test the gaseous pollutants with various apparatuses.
Air pollution index is derived by collecting all the recorded major pollutants in
the air including suspended particulates, sulphur dioxide, carbon monoxide,
ozone and nitrogen dioxide and transferring the data to numerical value ranges
from 0 to 500.
Air Pollution Control
To protect public health and maintain good air quality, the government has
established the “Air Pollution Control Ordinance” for regulating the sources of air
pollution and applying measures to minimize air pollution.
 establish law to lower the sulphur content in industrial diesel so that the amount
of sulphur dioxide in the air can be substantially reduced.
 strictly control of the sources of air pollution, such as power plants and cement
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factories, ensuring that the discharged pollutants are within the acceptable
standard laid down by the EDP.
regulate the discharge of exhaust air from eateries and dust from construction
sites. Outdoor burning activities are also forbidden.
strictly control of the discharge of exhaust fumes from vehicles; introducing the
use of environmental friendly fuel, encouraging taxi to use LPG instead of diesel;
funding the installation of particles filter; enforcing vehicle inspection and
reporting of vehicles emitting black fumes; setting up more pedestrian zones, etc.
5.
Improving indoor air quality
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If indoor ventilation is not good or if there is insufficient supply of fresh air,
carbon dioxide or other pollutants will gather and indoor air pollution will be
resulted.
Construction materials such as mud and stone, especially granite, will release
radon, which is a volatile gas and can cause diseases like lung cancer.
New fibre-board furniture will release a harmful gas called formaldehyde, which
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is volatile and can cause cancer.
If indoor air circulation system is not properly maintained, it will provide the
ideal growing environment for germs and bacteria. These will become the indoor
biological pollutants.
Suggestions for Utilization
The teacher is advised to show the whole programme in one lesson. For better
utilization, the teacher may spend 5 to 10 minutes at the beginning of the lesson to
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lead students to discuss with reference to the Preparation before viewing the
programme part of the Suggested Activities. The teacher may then show the
programme. After showing the programme, the teacher may spend another 10 to 15
minutes to discuss with students with a view to consolidating the concepts illustrated
in the programme, or extending the parts relating to conservation of wildlife and
natural environment for environmental education purposes. The teacher is advised to
refer to the Activities after viewing the programme part of Suggested Activities.
Suggested Activities
Preparation before viewing the programme
Teachers can conduct a casual chat with students asking them to voice out their
opinions on air pollution. Teachers can suggest some practical solutions to improve air
quality and then ask the students to watch the programme carefully.
Activities after viewing the programme
1. According to the five different sections in the programme, teachers can divide
students into groups and ask them to collect information about air pollution and
then present to the whole class.
2. Teachers may ask students to record the air pollution index within the days of a
particular month and present the data in a graph chart. Students are then required
to analyze the cause for change in the index.
3. Students may participate in a role-play on a mock debate in the Legislative
Assembly. Students can play the role of either the government spokesmen or the
councilors in a discussion on how to improve air quality. Students can participate
in a debate on the advantages and disadvantages of the suggested solutions.
4. Teachers may demonstrate experiments on testing the exhaust fumes from
vehicles. First collect fumes from exhaust pipes with plastic bag and pass the gas
into test tubes containing different testing reagents. Students are requested to note
down the observations so as to understand the chemical nature of the exhaust
fumes.
Testing reagents
Blue litmus solution
Observable changes
from blue to red
Lime water
Acidified potassium
permanganate
Fresh chicken blood
from colourless to milky
Implication
containing acidic gas (sulphur
dioxide, carbon dioxide or
nitrogen dioxide)
may contain carbon dioxide
from purple to colourless
from red to cherry red
may contain sulphur dioxide
may contain carbon monoxide
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