Life Cycle Assessment (OCR Gateway GCSE Chemistry)

• 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

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 fueled 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  The disposal of outdated products has an impact on the environment which may include: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

The Table below shows an LCA for a Plastic and Paper Bag 

Conclusion:

• Considering both life-cycle assessments, the plastic bag may be the better option
• Even though they aren’t biodegradable and are also produced from a finite resource, 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