ANW
People travel much more than they used to. As a result much more fuel is being used. Fuels are
valuable because they provide us with energy. By burning these fuels gasses are produced which are
bad to our health. Carbon dioxide, produced when burning greenhouse gasses the global climate to
change. People worry about the damage the climate change can cause. The air quality becomes less.
Air pollution can cause serious damage to people with heart- and lung diseases.
Fuels for transport
As fuel burns, chemical reactions give out energy. Sometimes this energy is directly used to make a
car engine run of a jet engine. It can also be used to make electricity. The electricity is used for trains,
trams or electric cars. Electricity is a secondary energy source. Fuel fuels such as oil, coal and natural
gas, are only available for a limited time. Eventually they will run out. Burning those fuels has done
more than anything to increase the concentration of greenhouse gasses in the air. The products of
burned fuels do not simply disappear. CO2 is the main greenhouse gas. Transport is the main reason
why there are so many greenhouse gasses in the atmosphere.
Alternatives to fossil fuels (biofuels)
Biofuels come from plants. Bioethanol comes mainly from sugars and starches. Biodiesel mainly
comes from rapeseed and palmoil. These biofuels are mixed with normal fuels. In theory these fuels
are carbon-dioxide neutral. The CO2 that is released from burning these energies has previous been
taking in by the plants to grow. In practice this doesn’t turn out to be this way. During the stages of
growing, harvesting and processing these plants also causes CO2 emission due to the use of farmingvehicles. It is said that producing biofuels is not the most effective way of using biomass. A British
report said that the most effective way is burning biomass and using the heat for generating
electricity. The biofuels which offer the most energy are crops from tropical countries. In Brazil
ethanol is made by fermenting sugars from sugar cane. The refineries use the waste from the sugar
cane for heating and generating energy. There is one huge disadvantage is that huge forests have
been cut down to make room for these refineries.
The idea of energy
energy does not have a simple definition. Energy also has two meanings. One of the meaning is the
amount of change that an object can cause to happen. Energy can be transferred from one object to
another by force, by heating, by radiation or by electricity. The amount of energy used can be
calculated in many different ways. Energy is always conserved in a progress. ‘Energy is always
conserved in a progress’.
Energy conservation has a different meaning in everyday life. It refers to the fact that energy sources
like fossil fuels are in a limited supply and are valuable. ‘World energy consumption has risen steadily
over the past decade. We need to takes steps to conserve energy’.
Why does burning fuels cause pollution?
Carbon dioxide produced with the burning of fossil fuels does affect the global climate, but doesn’t
affect the air quality. Engines pollute the air with gasses that are harmful for different reasons:
1. Sometimes the fuel is not burnt completely which causes the production of CO (instead of CO2).
2. The fuel contains other chemicals as well as hydrocarbons (CₓHₓ)
3. Fuel is burned under high pressure which causes oxygen and nitrogen to react and form NOₓ.
Carbon monoxide (CO)
Oxides of nitrogen, NO and NO₂. Also NOₓ
Sulfur dioxide (SO₂)
Ozone (O₃)
Particulates (fijnstof)
Volatile organic compounds (VOC’s) which are
normally gasses or liquids but evaporate so
easily that their vapours stay in the air.
(vluchtige organische stof)
Procudes when fuel is not completely burned, so
when theres not enough oxygen
Mainly from engines. Due to the pressure and
high temperature oxygen and nitrogen react
Burning fuels used in motor engines contrain
sulfur. Main source is coal from which burning
fuel is made.
Formed when sunlight shines on polluted air
which contains NOₓ
The particles include dust from roads and
industries. Fines particles are from in diesel
engines. SO2 and NO2 react and from particles
Include a wide variety of CₓHₓ from evaporated
fuels. Another source is leakage from pipelines.
Ozone and its effects
The ozone layer in the upper atmosphere is a good thing. It protects us from UV-radiation. Ozone in
the lower atmosphere is harmful. Ozone is a very reactive gas which irritates the eyes and causes
breathing difficulties. Ozone is toxic and can affect the growth of crops and other plants. Most of the
pollutants are primary pollutants. Ozone is a secondary pollutant. It is formed from NO2. Sunlight
splits up the NO2 into NO and O. The free oxygen molecule reacts with O2 and forms O3.In sunny
weather the Ozone level rises and mixes with VOC’s. This forms a yellow haze (smog) and a soup of
irritating chemicals.
Monitoring air quality
the aims of monitoring the air quality are to
- understand the scale of air pollution so that the authorities can devise cost effective ways of dealing
with the problems.
- See if the standers are met.
- Inform the public about air quality who may be at risk.
Different errors can be made. There are random errors, which cause repeat measurements to vary
and scatter around a mean value. These errors can be avoided by calculating an average value of
these measurements. Another type of error is systematic error: an error which affects all the
measurements. Systematic errors can occur when, for example, the instruments used do not work as
they should be.
Sampling and analysis
Taking a sample is an important first step of monitoring air quality. It is important to make sure that
the sample taken is representative for the air in the place where pollution is measured. For example,
a sample taken in the centrum of London is not representative for a suburb of London. There are
different ways of sampling. One method is to pump air through an analyzer. A systematic error than
can occur is that the material of the analyzer can absorb some of the chemicals. Another method is
to grab a sample of air in a bag. There will always be uncertainty the results.
How do air pollutants affect human health?
People working outside all day are more exposed to pollutants than people who work on an office.
The evidence about the effects of air pollutants on health is complex. Research has shown that the
main damage to people is done by fine particles which carry chemicals which include unburned
hydrocarbons.
How can technology improve air quality?
Changing the way people traffic is practically impossible, since many people are dependent on the
traffic. To change the air quality we have to use the technology. Catalytic converters are placed in
cars and convert chemicals produced with the burning of fossil fuels in the engine into non-harmful
gasses (NOₓ, CₓHₓ and CO into CO2, N and H2O). They do not reduce CO2 emission. In fact, they make
it slight worse since.
Eletric vehicles have a great advantage that they don’t have emit air pollutants. Disadvantages are
that they have to be regularly charged. An alternative to batteries is to use fuel cells. A fuel cell is like
a battery, but instead of containing a fixed amount of chemicals, it is supplied with a flow hydrogen
gas and air. The hydrogen reacts with the air, forming electricity and water vapor. Also using public
transport reduces the emission of air pollutants.
How can regulations improve air quality?
Since 1970 there have been different rules and regulations to reduce the emission of greenhouse
gasses and air pollutants.