LCAs Flashcards
(9 cards)
1
Q
4 stages in life cycle assessments
A
- extracting and processing raw materials
- manufacturing and packaging
- use and operation during its lifetime
- disposal at the end of its useful life, including transport and distribution at each stage
2
Q
problems of LCAs
A
- effects of pollutants are difficult to quantify, meaning we have to use value judgements, so not purely objective
- selective or abbreviated LCAs can be devised to evaluate a product but these can be misused to reach pre-determined conclusions, eg in support of claims for advertising purposes
3
Q
explain step 1
A
- extracting raw materials can damage local environment
- also result in pollution due to amount of energy required
- processing often requires large amounts of energy
4
Q
explain step 2
A
- manufacturing products and their packaging can use a lot of energy resources
- also cause a lot of pollution
- can produce waste products which can be turned into other chemicals, reducing pollution or disposed of unethically
5
Q
explain step 3
A
- use can damage the environment
- e.g burning fuels releases greenhouse gases
- e.g fertilisers can leach into streams damaging ecosystems
- products that need lots of energy to produce but last longer may mean less waste in long run
6
Q
explain step 4
A
- often disposed in landfill sites
- takes up space
- pollutes land and water
- energy use to transport waste, releasing pollutants
- products may be incinerated, which releases air pollution
7
Q
plastic bag LCA
A
- made from hydrocarbons obtained from crude oil (cheap, plentiful) by fractional distillation, followed by cracking then polymerisation. little waste as the other fractions of crude oil have other uses
- processed into long roll of film, cut into shape, requires energy, packaged in cardboard boxes
- constantly reusable, (strength) can be used as other things such as bin liners, no environmental impact
- recyclable but not biodegradable so take up space in landfill and pollute land
- transported from oilrig to processing plant, to manufacturer to shops to landfill, does release pollution
8
Q
paper bag LCA
A
- made from timber (renewable) but obtained via deforestation. a lot of wood required, pulping and processing so lots of energy required, unusable waste
- rolled into long sheets, cut into shape, machinery requires energy, packaged in cardboard boxes
- unable to reuse if wet, relatively weak so only one use therefore more needed to make
- recyclable but requires energy, are biodegradable and non-toxic so break down without causing pollution
- timber transported from forest to processing plant to manufacturer to shops, releases pollution
9
Q
paper v plastic
A
-plastic is better
-despite being non-biodegradable they take less energy to make and have a longer lifespan