LCA and the environment

• Main stages of a life-cycle assessment

  • Extracting and processing the raw materials
  • Manufacturing the product and its packaging
  • Using the product during its lifetime
  • Disposing of the product at the end of its useful life
• Modern metal extraction can reduce the impact on the environment
• Life-cycle assessments can evaluate the environmental impact of a product
• Impacts of obtaining raw materials

  • Using up limited resources such as ores and crude oil
  • Damaging habitats through quarrying, mining, or felling trees
• Four main stages of the life-cycle assessment: Raw materials, Manufacture, Use, Disposal
• The impact of a product on the environment during its use

  Depends on the type of product
• Raw material


  Basic material that goods are made from such as crops, metals, wood, and animal products such as wool and leather
• Life-cycle assessment

  A 'cradle-to-grave' analysis of the impact of a manufactured product on the environment
• Many products are recycled to lessen environmental impact
• Impacts of manufacturing products

  • Using up land for factories
  • The use of machines and people
• Impacts of disposing old products

  • Using up land for landfill sites
  • Whether any or all of the product can be recycled or reused
• Manufacture of Paper carrier bags

  • More expensive to make bags from paper because the handles must be glued on
• Raw materials for Paper carrier bags

  • Can be made from recycled paper, or from trees. Making paper from trees requires more energy than recycling paper, but much less than making plastics
• Energy use could be significantly reduced by

  Drying the pillowcase outside and without ironing it, and washing it at a lower temperature
• It is important to consider who has completed the LCA and whether they have any bias
• Disposal of Paper carrier bags

  • Can be recycled easily; if disposed of in landfill, they biodegrade quickly
• Use of Paper carrier bags

  • Relatively short lifetime; can only be reused a limited number of times
• One quarter of the energy use is associated with making the pillowcase, and very little in disposing of it. The greatest use of energy happens when it is being used, probably because of washing, drying and ironing the pillowcase.
• Comparative LCAs can be used to evaluate which of two alternative products will have a lower negative impact on the environment
• Manufacture of Plastic carrier bags

  • Cheaper to make large quantities of bags from plastic
• Use of Plastic carrier bags


  • Lower impact on the environment because plastic bags are usually stronger so they can be reused many times
• Raw materials for Plastic carrier bags

  • Crude oil is a finite resource; fractional distillation, cracking and polymerisation all require a lot of energy
• Disposal of Plastic carrier bags

  • Can sometimes be collected and recycled; if disposed of as litter, they do not biodegrade; in landfill, may take decades or centuries to degrade
• It is sometimes easy to work out accurate numerical values for parts of a LCA. However, some parts require judgements, such as the effect of pollutants, making it not a totally objective process. Different people might come up with different judgements
• Energy


  The capacity of a system to do work or the quantity required for mechanical work to take place, measured in joules (J)
• Greenhouse gases

  • Carbon dioxide, methane, nitrous oxide, CFCs (chlorofluorocarbons)
• Natural resources

  Minerals made through the formation of the world that can be used for human benefit
• Many products are recycled to lessen environmental impact
• Glass bottles only need to be washed and sterilised before they can be filled again
• Recycling


  Reusing materials or reprocessing waste materials to produce new materials
• Some items made from natural resources can be reused, saving energy and reducing the impact on the environment
• Life-cycle assessments can evaluate the environmental impact of a product
• Modern metal extraction can reduce the impact on the environment
• Materials made from limited natural resources

  • Metals, glass, building materials, clay ceramics, most plastics
• Advantages of recycling include fewer quarries and mines needed, less crude oil extraction, reduced greenhouse gas emissions, and less waste in landfill sites
• Environment


  The immediate surroundings in which people live, or the natural world such as the land, air, or water
• Aluminium is extracted from its ore using electrolysis but iron is extracted by heating with carbon
• The amount of sorting required depends on the purity of the mixture of metals/materials and how pure the final recycled metal needs to be
• Scrap iron can easily be added to the steel furnace when steel is being made, reducing the cost of making steel from iron ore
• Disadvantages of recycling


  • The collection and transport of used items needs organisation, workers, vehicles, and fuel
  • It can be difficult to sort different metals from one another
  • The sorted metal may need to be transported to where it can be turned into ingots