Carbon Footprint and Atmospheric PollutantsAQA GCSE Chemistry: Revision notes
Section 1
What Is a Carbon Footprint?
A carbon footprint is the total amount of carbon dioxide and other greenhouse gases emitted over the full life cycle of a product, service or event — from making it, through using it, to disposing of it.
Understanding a carbon footprint helps identify where emissions come from, so they can be targeted for reduction.
'Full life cycle' is the key phrase examiners look for — not just the emissions from using the product, but making and disposing of it too.
Section 2
What Pollutants Come From Burning Fuels?
The combustion of fuels is a major source of atmospheric pollutants. Burning fuels can release:
- Carbon dioxide and water vapour
- Carbon monoxide
- Sulfur dioxide
- Oxides of nitrogen
- Unburned hydrocarbons
- Solid particles (particulates), also called soot
Carbon monoxide, soot, sulfur dioxide and oxides of nitrogen are all produced by burning fuels — the exact products depend on the fuel's composition and the conditions of combustion (for example, whether combustion is complete or incomplete).
A car engine running with a limited air supply produces carbon monoxide and soot due to incomplete combustion.
Section 3
What Problems Do These Pollutants Cause?
| Pollutant | Problem caused |
|---|---|
| Carbon monoxide | A toxic, colourless, odourless gas — dangerous because it cannot be detected by smell or sight |
| Sulfur dioxide | Causes respiratory problems and contributes to acid rain |
| Oxides of nitrogen | Cause respiratory problems and contribute to acid rain |
| Particulates | Cause global dimming and health problems |
Carbon monoxide poisoning is especially dangerous precisely because it's colourless and odourless — victims often don't notice it.
Section 4
How Can Carbon Footprints Be Reduced?
Actions to reduce emissions of carbon dioxide and methane include using renewable energy sources, improving energy efficiency, and changing agricultural or waste management practices.
However, such actions may be limited by factors such as cost, availability of alternative technology, and international cooperation — reducing a carbon footprint is rarely simple or immediate.
Must Know
- A carbon footprint is the total greenhouse gas emissions across a product, service or event's full life cycle
- Burning fuels produces pollutants including carbon monoxide, sulfur dioxide, oxides of nitrogen and particulates (soot)
- Carbon monoxide is toxic, colourless and odourless
- Sulfur dioxide and oxides of nitrogen cause respiratory problems and acid rain
- Particulates cause global dimming and health problems
- Actions to reduce carbon dioxide and methane emissions exist, but may be limited by cost and other practical factors
That's the notes covered.
Carry on to the next subtopic.