Atmospheric Pollution

Question 1

What are green house gases

Answer 1

• carbon dioxide, methane and water vapour act like an insulating layer in the Earth’s atmosphere. This helps it keep warm enough to support life

Question 2

Describe the greenhouse effect

Answer 2

• sun emits short wavelength radiation, greenhouse gases can’t absorb it
• the earth reflects these wavelengths as long wavelength radiation which the greenhouse gases can absorb
• They then re-radiate it in all directions-including back towards earth
• The long wave radiation is thermal radiation, so it results in warming of the surface of the Earth. This is the greenhouse effect

Question 3

What human activities affect the amounts of greenhouse gases in our atmosphere

Answer 3

• deforestation —> fewer trees mean fewer CO2 removed from atmosphere via photosynthesis
• Burning fossil fuels —> releases carbon ‘locked up’ as CO2
• Agriculture —> more farm animals release methane through their digestive processes
• Creating waste/landfill—> decomposition releases methane

Question 4

What is the composition of gases in atmosphere today

Answer 4

• 78% nitrogen
• 20.9% oxygen
• 0.90% Argon gases
• O.03% carbon dioxide
• 0.17% other gases

Question 5

What are the effects of pollutants

Answer 5

• CO2 increases temp, global warming
• CO it toxic. Binds to haemoglobin in blood instead of oxygen
• C makes buildings dirty, cause irritation to respiratory system and global dimming
• SO2 dissolves in water, this makes acid rain. Harms crops, buildings, respiratory system and kills water ecosystems
• NOx causes Acid rain, forms photochemical smog
• unburnt hydrocarbons are carcinogenic

Question 6

What are the different pollutants and how do they form (6)

Answer 6

• CO2 : complete combustion of fuel
• H2O : combustion of fuel
• C : complete combustion of fuel
• SO2 : sulfur impurities in fuel that react with O2
• NOx : nitrogen reacts with oxygen in heated temps
• CH4: unburnt hydrocarbons in fuel