C10 Life Cycle Assessments (page 163)

Question 1

What is a Life Cycle Assessment? (LCA)

Answer 1

it looks at every stage of a product’s life to assess the impact it would have on the environment.

1. getting the raw materials
2. manufacturing and packaging
3. using the product
4. product disposal

Question 2

What is the Life cycle assessment for

Getting the Raw material?

Answer 2

1. Extracting the raw materials needed for a product, but this can damage the local enviornment e.g. mining metals. Extraction also result in pollution due to the amount of energy needed
2. Raw materials often need to be processed to extract the desired materials and this often needs large amounts of energy. e.g. extracting metals from ores or fractional distillation of crude oil.

Question 3

What is the Life cycle assessment process for:

Manufacture and packaging?

Answer 3

1. Manufacturing products and their packaging can use a lot of energy resources and can also cause a lot of pollution e.g. harmful fumes such as carbon monoxide or hydrogen chloride.
2. You also need to think about any waste products and how to dispose of them. The chemical reactions used to make compounds from their raw materials can produce waste products. Some waste can be turned into other useful chemicals, reducing the amount that ends up polluting the environment.

Question 4

What can the Life Cycle stage of using a product do to the environment?

Answer 4

1. The use of a product can damage the environment. for example, burning fuels releases greenhouse gasses and other harmful substances. Fertilisers can leak into streams and rivers causing damage to ecosystems.
2. How long a product is used for or how many uses it gets is also a factor - products that need lots of energy to produce but are used for ages mean less waste in the long run.

Question 5

What is the Life Cycle assessment for:

Product Disposal?

Answer 5

1. Poducts are often disposed of in landfill sites. This takes up space and pollutes land and water. e.g. if paint washes off a product and gets into rivers.
2. Energy is used to transport waste to landfill, which causes pollutants to be released into the atmosphere.
3. Products might be incinerated (burnt) which causes air pollution.

Question 6

What is the Life cycle Assessment stage for:

Plastic Bags?

Answer 6

Raw Material: Crude Oil

Manufacturing & Packaging: The compounds needed to make the plastic are extracted from crude oil, by fractional distillation, followed by cracking and then polymerisation. Waste is reduced as the other fractions of crude oil have other uses.

Using The product: can be resued. Can be used for other things as well as shopping for example bin liners.

Product Disposal: Recyclable but not biodegradable (will not breakdown in the soil) and will take up space in landfill and polute land.

Question 7

What is the Life Cycle Assessment for:

Paper Bags?

Answer 7

Raw Materials: Timber

Manufacturing and Packaging: Pulped timber is processed using lots of energy. Lots of waste is made.

Using the Product: Usually only used once

Product Disposal: Biodegradable, non-toxic and can be recycled.

Question 8

Explain what the life cycle assessments tells us regarding plastic bags and paper bags?

Answer 8

They show that even though plastic bags aren’t biodegradable, they take less energy to make and have a longer lifespan than paper bags, so may be less harmful to the environment.

Question 9

Explain why there are problems with Life Cycle Assessments?

Answer 9

The use of energy, some natural resources and the amount of certain types of waste produced by a product over it’s lifetime can be easily quantified (able to be measured). But the effect of some pollutants is harder to give a numerical value to. e.g. it’s difficult to apply a value to the negative visual effects of plastic bags in the environment compared to paper ones.

So producing an LCA is not an objective method as it takes into account the values of the person carrying out the assessment. This means LCAs can be biased.

Question 10

What is Selective LCA’s (Life Cycle Assessments)?

Answer 10

It only shows some of the impacts of a product on the environment, so can also be biased as they can be written to deliberately support the claims of the company, in order to give them positive advertising.

Question 11

What are the four states that need to be considered to conduct a life cycle assessment? (4 marks)

Answer 11

Choice of material

manufacturing and packaging

using the product

product disposal

(1 mark for each)