AQA GCSE Chemistry

Revision Notes

10.2.1 Life Cycle Assessment

Total Environmental Impact

  • A life cycle assessment (LCA) is an analysis of the overall environmental impact that a product may have throughout its lifetime
  • The cycle is broken down into four main stages which are:
    • Raw Materials
    • Manufacture
    • Usage
    • Disposal

Life Cycle Assessment - Flow Diagram, IGCSE & GCSE Chemistry revision notes

Diagram showing the four stages in a life-cycle assessment

  • Obtaining the necessary raw materials has an impact on the environment which may include:
    • Using up limited resources such as ores and crude oil
    • Damaging habitats through deforestation or mining
  • Manufacturing processes also have an impact on the environment which may include:
    • Using up land for factories
    • The use of fossil fuelled machines for production and transport
  • Usage of a product may also affect the environment although it depends on the type of product
  • For example, a wooden desk has very little impact whereas a car will have a significant impact (air pollution)
  • The disposal of outdated products has an impact on the environment which may include:
    • Using up space at landfill sites
    • Whether the product or its parts can be recycled
  • A life cycle assessment is carried out using the data of a given product and the criteria of the assessment
  • Rarely is there a perfect product with zero environmental impact, so often a compromise is made between environmental impact and economical factors

Exam Tip

Life cycle assessments are objective exercises as it is difficult to quantify each stage. LCA’s can therefore be biased.

Lifecycle Assessment of Shopping Bags

Example
An LCA can be carried out on plastic and paper shopping bags.

LCA for Plastic and Paper Bags, downloadable IGCSE & GCSE Chemistry revision notes

Conclusion

  • Considering both life-cycle assessments, the plastic bag may be the better option. Even though they aren’t biodegradable, they do have a much longer lifespan and thus are less harmful than paper bags
  • Much depends on the usage of the item:
    • If the paper bag is recycled then it could be more favourable to use it
    • If the plastic bag is used only once, then then the argument for using plastic bags is less favourable

Author: Francesca

Fran has taught A level Chemistry in the UK for over 10 years. As head of science, she used her passion for education to drive improvement for staff and students, supporting them to achieve their full potential. Fran has also co-written science textbooks and worked as an examiner for UK exam boards.
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