1. 23/05/2018
Air Quality
(OCR)
W Richards
The Weald School

2. The Earth’s Atmosphere
23/05/2018
Present day atmosphere contains 78% nitrogen, 21% oxygen, 1% noble gases and about 0.03% CO2
Carbon dioxide, water vapour
Oxygen
Nitrogen
Noble gases

3. Pollution Humans pollute the Earth in a number of ways: Pollutant
23/05/2018
Humans pollute the Earth in a number of ways:
Pollutant
Harmful to...
Why?
Carbon dioxide
Environment
Nitrogen oxides
Environment + humans
Sulfur dioxide
Particulates (e.g. Smoke)
Carbon momoxide
Humans
A greenhouse gas that causes global warming
Causes acid rain and makes asthma/breathing problems worse
Causes acid rain
Makes buildings dirty and makes asthma worse
Displaces oxygen in red blood cells that can result in death

4. Measuring pollution Low concentration High concentration
23/05/2018
Low concentration
High concentration
Concentration is measured in Parts per Million (ppm) or Parts per Billion (ppb).

5. Carbon monoxide concentration (ppm)
Some sample data
23/05/2018
Location
Time
Carbon monoxide concentration (ppm)
London
9am
11am
1pm
3pm
5pm
6.4
6.2
5.9
3.1
6.3
The Cotswolds
0.2
0.1

6. These atoms are ALL iron – there’s nothing else in here
Elements
23/05/2018
If a solid, liquid or gas is made up of only one type of atom we say it is an element. For example, consider a tripod made up of iron:
These atoms are ALL iron – there’s nothing else in here

7. Sodium chloride (salt)
Compounds
23/05/2018
Compounds are different to elements. They contain different atoms. Here are some examples:
Sodium chloride (salt)
Methane
Glucose

8. Some simple compounds…
23/05/2018
Methane, CH4
Carbon dioxide, CO2
Water, H2O
Key
Hydrogen
Oxygen
Carbon
Sulphur
Sulphuric acid, H2SO4
Ethyne, C2H2

9. Simple chemical reactions
23/05/2018 Mg O H Cl
Magnesium oxide +
Hydrochloric acid
Magnesium chloride +
Water
MgO +
2HCl
MgCl2 +
H2O Mg O Cu S
Magnesium +
Copper sulphate
Copper +
Magnesium sulphate Mg +
CuSO4 Cu +
MgSO4

10. Burning Fuels – “Combustion”
23/05/2018 C H O O H C O
Lots of oxygen:
Methane
Oxygen +
Carbon dioxide
Water +
Water + O H
Methane C H
Oxygen + O C O
Some oxygen:
Carbon monoxide O H
Water + C H
Methane
Little oxygen: O
Oxygen + C
Carbon

11. Other products of burning fuels
23/05/2018 S O
Sulphur dioxide
Sulphur dioxide: S O
Sulphur
Oxygen +
Nitrogen monoxide N O
Oxygen + O
Nitrogen N
Nitrogen monoxide: O
Oxygen +
Nitrogen monoxide N
Nitrogen dioxide N O
Nitrogen dioxide:

12. Pollution What happens to pollution?
23/05/2018
What happens to pollution?
Carbon dioxide causes global warming but some of it can be removed by plants (photosynthesis) or reactions with seawater.
Sulfur dioxide and nitrogen dioxide cause acid rain which damages trees and buildings.
Particulates (like in smog) can make buildings dirty and worsen breathing difficulties.

13. Removing Pollution There are many ways pollution can be reduced:
23/05/2018
There are many ways pollution can be reduced:
Use less electricity/central heating
Remove toxic chemicals before or after they are burnt
Use alternative energy sources, e.g. wind power

14. Reducing Pollution from vehicles
23/05/2018
A number of suggestions:
1) Buy a new, smaller, cleaner car
2) Buy a “hybrid” car
3) Convert your car to run on biodiesel
4) Make sure your car has a catalytic converter:
Carbon monoxide + oxygen carbon dioxide
Nitrogen monoxide + carbon monoxide nitrogen + carbon monoxide
5) Use the train or a bus!

15. Making choices about pollution
23/05/2018
Choices concerning fighting pollution can be made on many levels:
International
e.g. The Kyoto protocol in 1997
National
e.g. Car tax system, subsidies for greener technology
Local
e.g. Recycling schemes, transport, congestion charges
Personal
e.g. Recycling, individual travel, reducing energy usage in the home etc