Unit 4: Lesson 6: The Greenhouse Effect & Air Pollution Flashcards
What do Ultraviolet (UV) rays from the sun hit?
Earth
What does the Earth absorb and what does the Earth emit?
The Earth absorbs UV rays and emits infrared rays.
What do infrared rays do to the air?
Infrared rays heat the air.
What can infrared rays be absorbed by?
Infrared rays are sometimes absorbed by greenhouse gases.
What greenhouse gases traps heat?
Carbon Dioxide.
Water Vapour.
Methane.
Nitrous Oxide. (Naturally occurring)
CFCs (Released by humans)
What are the greenhouse gases?
- Carbon Dioxide (CO2)
- Water Vapour (H2O)
- Methane (CH4)
- Nitrous Oxide (N2O)
- CFCs (chlorofluorocarbons)
Describe the greenhouse effect.
- Temperatures rise.
- Temperatures rise and polar ice caps melt. This raises sea levels.
- Raised sea levels causes floods, affects wildlife and removes land mass, affecting our economy and lives.
- A rise in sea temperature could redirect ocean currents, bringing warm water to cooler areas. This could affect the ecology of the area.
- The water vapour levels will rise as more water evaporates off the sea. This could affect the weather. Some species may need to migrate to new ecosystems.
What are the causes of CO2 increase?
CO2 levels naturally rise & fall with the seasons as trees lose and grow leaves. However, since the industrial revolution, levels have risen considerably. Rising CO2 is caused by:
- Deforestation
- Fossil Fuel Use (Industry & Vehicles)
- Overpopulation
What is deforestation and why does it cause CO2 levels to rise?
We cut down trees to make things or burn the wood. Trees photosynthesise, so take in CO2 & released O2. Cutting them down means the levels of CO2 rise.
What is fossil fuel use & why does it cause CO2 levels to rise?
We burn fossil fuels (coal, oil & gas) to produce energy and to make things. Burning fossil fuels releases CO2 that was trapped in dead organic matter (animals & plants).
What are the causes of methane increase?
When plants rot, methane is released. This occurs naturally, but also when food is wasted & left to rot in bins and landfill.
Farts contain a lot of methane. Cows fart a lot. Some people try to cut down on the amount of the methane released by eating less meat and dairy. Methane is released because of fermentation in the rumen (stomach) of the cattle.
What are the causes of nitrous oxide increase?
Nitrous oxide is naturally released by denitrifying bacteria in the nitrogen cycle.
However, fertiliser is the biggest cause of nitrous oxide being released into the atmosphere. The more plants & animals we farm, the more fertiliser we use.
Vehicles also produce nitrous oxides.
What are the causes of CFCs?
CFC levels are decreasing as they were banned decades ago.
They used to be in refrigerators and aerosol cans.
Now CFCs released are from these old items left on landfill.
What does burning fossil fuels (coal, natural gas & oil) release? What does this cause?
Carbon monoxide (CO), carbon dioxide (CO2), and sulfur dioxide (SO2). These all cause air pollution.
What are the main reasons for burning fossil fuels?
To fuel cars with internal combustion engines & power plants creating energy to power our homes and industry (factories).
Explain the mechanism of the internal combustion engine.
Pistons are a crucial part of most car engines. Fuel e.g. petrol is spurt into the top of the piston. The fuel is ignited by a spark or heat source, which forces the piston down. The action is continually repeated. This moves the piston up and down, turning a pole attached to the wheels to make them turn.
These are called combustion engines BECAUSE they use combustion (burning) to make the car move.
Explain combustion in power plants.
Power plants also burn fossil fuels to move things (turbines).
In a coal plant, coal is burnt. This heats water to create steam. The steam turns turbines. The turning motion of turbines is used to create electricity.
When is carbon monoxide produced?
When fossil fuels are burnt in little air e.g. an engine or power plant.
Many cars have catalytic converters. What does this convert?
Catalytic converters convert CO to CO2, which is less harmful to humans directly.
How does CO cause death?
CO combines with haemoglobin in red blood cells, preventing them from carrying oxygen (and carbon dioxide).
Oxygen doesn’t reach the cells and carbon dioxide cannot be removed as a waste product.
If oxygen cannot reach the heart or brain, death occurs.
Does fossil fuel contain sulfur?
Fossil fuels contain smaller amounts of sulfur.
When fossil fuel is burnt, what does sulfur mix with and what does it produce?
Sulfur can mix with oxygen to produce sulfur dioxide (the oxide part of the name represents the oxygen).
Then, what can sulfur dioxide (SO2) mix with in the air to produce what?
Sulfur dioxide (SO2) mixes with water vapour in the air to make sulfuric acid. This falls as acid rain (rain with a low pH).
What are the negative biological consequences of acid rain?
Acid rain can harm lake ecosystems, killing organisms which cannot cope with the drop in pH.
It kills trees by damaging their leaves (preventing photosynthesis) and releasing toxic substances in the ground so they can’t absorb minerals from the soil.
Acid rain corrodes statues and other architectural treasures.
