Life cycle assessment and recycling

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Life Cycle Assessment (LCA)

A life cycle assessment (LCA) analyses the overall environmental impact of a product throughout its entire lifetime.
An LCA is broken down into four main stages: raw materials, manufacture, usage, and disposal.
The raw materials stage considers using up limited resources (such as ores and crude oil) and damaging habitats through deforestation or mining.
The manufacture stage includes using land for factories, burning fossil fuels for production and transport, and producing waste.
The usage stage depends on the product: a wooden desk has little impact, while a car produces significant air pollution.
The disposal stage considers using up landfill space and whether the product or its parts can be recycled.

The four stages of a life cycle assessment

Carrying Out an LCA

Some parts of an LCA are easily quantified, for example the amount of water used or the quantity of waste produced.
Other parts are difficult to give a numerical value to, such as the polluting effect of a product.
In these cases, people make a value judgement, which is not objective and can be biased.
There is rarely a product with zero environmental impact, so a compromise is often made between environmental impact and economic factors.
Abbreviated LCAs may be used in advertising to highlight environmental benefits without showing negative impacts.

Using LCA evidence carefully

Comparative LCA: Plastic vs Paper Bags

Plastic bags are made from crude oil, a finite resource; paper bags come from trees or recycled paper.
Making paper requires more energy than recycling paper, but much less than making plastics.
Plastic bags are cheap to manufacture and reusable many times; paper bags are biodegradable and non-toxic but most are not reusable.
Plastic bags can be recycled but this is costly and produces pollution; they are not biodegradable and take up landfill space.
Overall, the plastic bag may be the better option because it has a much longer lifespan, even though it is not biodegradable.
The conclusion depends on usage: if a paper bag is recycled it may be more favourable; if a plastic bag is used only once, the argument for plastic is weaker.

Comparing plastic and paper bags using LCA

Reducing Use of Resources

Everyday materials such as glass, metal, plastics and ceramics are produced from natural but finite sources.
Reuse and recycling cut down the use of limited material resources, reduce energy use and decrease waste production.
Some products can be reused directly, which saves energy and decreases environmental impact.
For example, glass bottles only need to be washed and sterilised before they can be reused.
Other products cannot be reused but can be processed and recycled for a different use.

Reuse and recycling reduce resource use

Recycling Metals and Glass

Metals can be recycled by melting and recasting or reforming into new products.
The amount of separation required depends on the metal and the properties required of the final product.
In steel making, scrap steel is added to iron from a blast furnace, reducing the amount of iron that needs to be extracted from iron ore.
Glass that cannot be reused is separated by colour and composition, then crushed, melted and remoulded into new shapes.
Glass, steel and concrete are usually produced from finite resources.

Reuse and recycling reduce resource use

Advantages of Recycling

Recycling metals is economically beneficial, especially for metals that are costly to extract such as aluminium.
Recycling provides employment and is becoming a major industry.
Recycling means less mining is required, reducing damage to the environment and ecosystems.
It is much more energy efficient to recycle metals than to extract them, as melting and remoulding requires less energy.
Recycling decreases waste, reducing the space needed at landfill sites.
Less mining and less energy use means fewer CO₂ and greenhouse gas emissions, reducing the contribution to global warming.

Disadvantages of Recycling

Collection and transport of material to be recycled requires energy and fuel.
Workers, vehicles and work sites need to be organised and maintained.
Materials need to be sorted before they can be recycled, which requires energy and labour.
Products made from recycled materials may not always be of the same quality as the original.

Benefits and trade-offs of recycling

Sustainability and Raw Materials

There is a limited supply of every material on Earth.
As global populations increase, there is a greater need for effective recycling to attain sustainable development.
Mining and extraction use up fossil fuels, which contributes to climate change.
Reducing, reusing and recycling materials by end users reduces the use of limited resources, energy sources, waste and environmental impacts.

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1.Which of the following is NOT one of the four main stages of a life cycle assessment?
Easy
- ARaw materials
- BManufacture
- CAdvertising
- DDisposal
2.Which stage of a life cycle assessment involves the use of fossil-fuelled machines for production and transport?
Medium
- ARaw materials
- BManufacture
- CUsage
- DDisposal
3.Why is a life cycle assessment not considered a purely objective process?
Medium
- AIt only considers the disposal stage
- BIt requires value judgements when allocating numerical values to pollutant effects
- CIt is always based on incomplete data
- DIt ignores the use of energy
4.Which of the following is an environmental advantage of recycling metals?
Medium
- AIt increases the amount of mining required
- BIt uses more energy than extracting metals from ores
- CIt reduces the amount of waste sent to landfill
- DIt produces more CO₂ emissions
5.Which of the following are environmental advantages of recycling? (Select all that apply)
Medium
- ALess mining is required
- BLess energy is used compared to extraction
- CMore waste is sent to landfill
- DFewer CO₂ emissions are produced
- ECollection and transport require energy
6.Reuse of a product saves more energy than recycling it.
Easy
True or false?
7.A life cycle assessment only considers the disposal stage of a product's life.
Easy
True or false?
8.Match each stage of a life cycle assessment to its environmental impact.
Medium
- Raw materials
- Manufacture
- Usage
- Disposal
- Using up limited resources such as ores and crude oil
- Using up land for factories
- Air pollution from a car
- Using up space at landfill sites

Mehr Fragen

9.Place the stages of a life cycle assessment in the correct order.
Medium
- Raw materials
- Manufacture
- Usage
- Disposal
10.Match each stage of a life cycle assessment to an example of an environmental impact that occurs during that stage.
Medium
- Raw materials
- Manufacture
- Usage
- Disposal
- Habitat damage from deforestation or mining
- Use of fossil-fuelled machines for production and transport
- Air pollution released while the product is being operated, such as by a car
- Using up space at landfill sites
11.Which of the following are disadvantages of recycling materials? (Select all that apply)
Medium
- ACollection and transport of recycled material requires energy and fuel
- BMaterials must be sorted before they can be recycled, which needs energy and labour
- CProducts made from recycled materials may be of lower quality than the original
- DRecycling reduces the space needed at landfill sites
- ERecycling decreases the need for mining
12.Place the stages of recycling glass bottles in the correct order.
Medium
- Glass is separated by colour and composition
- Glass is crushed
- Glass is melted
- Glass is remoulded into a new shape
13.Which raw material is used to manufacture poly(ethene) and poly(propene)?
Easy
- ACrude oil
- BWood
- CIron ore
- DLimestone
14.A company is considering using glass cups instead of disposable cups. Which of the following is a disadvantage of using glass cups?
Medium
- AGlass cups are heavy and can break easily
- BGlass cups cannot be recycled
- CGlass cups are made from a renewable resource
- DGlass cups are biodegradable
15.Which of the following are environmental advantages of recycling metals? (Select all that apply)
Medium
- ALess mining is required, so fewer CO2 emissions are produced
- BRecycling uses less energy than extracting metals from ores
- CLess waste is produced, reducing the space needed at landfill sites
- DCollection and transport of scrap metal requires energy and fuel
- ESorting scrap metal requires energy and labour
16.A life cycle assessment is a purely objective process.
Easy
True or false?
17.Which of the following correctly describes the difference between reuse and recycling?
Medium
- AReuse uses a product again for the same purpose, while recycling processes the material into a new product
- BReuse melts the material down, while recycling washes and sterilises it
- CReuse always requires more energy than recycling
- DReuse is only possible for metals, while recycling is only possible for glass
18.Match each material to the correct recycling process.
Medium
- Metals
- Glass
- Steel
- Melted and recast or reformed into new products
- Separated by colour and composition, then crushed and melted
- Scrap can be added to iron from a blast furnace to reduce iron extraction
19.A company wants to reduce the environmental impact of its glass bottles. Which of the following best describes the difference between reusing and recycling the bottles?
Medium
- AReusing involves washing and sterilising the bottles, while recycling involves crushing and melting them.
- BReusing involves crushing and melting the bottles, while recycling involves washing and sterilising them.
- CReusing means using the bottles for a different purpose, while recycling means using them again for the same purpose.
- DReusing is only possible for plastic bottles, while recycling is only possible for glass bottles.
20.A life cycle assessment of a product shows that 120 MJ of energy is used to extract and process raw materials, 200 MJ during manufacture, and 30 MJ during disposal. What percentage of the total energy is used during manufacture?
Medium
- A57%
- B40%
- C80%
- D20%
21.Which of the following statements about the objectivity of a life cycle assessment are correct? (Select all that apply)
Medium
- ASome stages, such as the amount of water used, can be easily quantified.
- BAllocating a numerical value to the polluting effect of a product is straightforward and objective.
- CValue judgements are needed when numerical values cannot be easily assigned.
- DDifferent people may allocate different values to the same environmental impact.
- EAn LCA is always completely free from bias.
22.Recycling metals such as aluminium is economically beneficial because it is costly to extract them from their ores.
Easy
True or false?
23.A comparative life cycle assessment shows that a plastic bag has a mass of 6 g and can be reused many times, while a paper bag has a mass of 55 g and is biodegradable. Which conclusion is best supported by this information?
Medium
- AThe plastic bag may have a lower environmental impact if it is reused many times.
- BThe paper bag always has a lower environmental impact because it is biodegradable.
- CThe plastic bag is better because it is made from crude oil.
- DThe paper bag is better because it is heavier.
24.A company claims its new product is 'environmentally friendly' based on an LCA that only considers disposal. Which of the following are reasons why this claim could be misleading? (Select all that apply)
Hard
- AThe LCA ignores the raw materials stage, which may involve mining and habitat destruction.
- BThe LCA ignores the manufacturing stage, which may use fossil fuels and produce waste.
- CThe LCA includes all stages of the life cycle, so it is reliable.
- DThe LCA may be used to support a pre-determined conclusion for advertising.
- EThe LCA only considers disposal, so it does not give the complete picture.
25.Which of the following is a disadvantage of recycling materials?
Medium
- ACollection and transport of materials requires energy and fuel.
- BIt reduces the amount of waste sent to landfill.
- CIt conserves raw materials.
- DIt reduces energy use compared to extraction.
26.The four main stages of a life cycle assessment are raw materials, manufacture, usage, and disposal.
Easy
True or false?
27.Which gas released by factories is matched to the environmental issue of global warming?
Easy
- ACarbon dioxide
- BSulfur dioxide
- CNitrogen
- DOxygen
28.A company claims its new disposable cup is 'environmentally friendly' because it is biodegradable. Which stage of the life cycle assessment does this information relate to?
Easy
- ARaw materials
- BManufacture
- CUsage
- DDisposal
29.A life cycle assessment of a product shows that 120 MJ of energy is used to extract and process raw materials, 200 MJ during manufacture, and 30 MJ during disposal. The usage stage uses 50 MJ. What is the total energy used in the life cycle?
Medium
- A350 MJ
- B400 MJ
- C370 MJ
- D320 MJ
30.Which of the following is a disadvantage of recycling plastic bottles?
Medium
- AIt reduces the amount of waste sent to landfill
- BIt saves energy compared to making new plastic
- CIt requires collection, transport and sorting which use energy and fuel
- DIt conserves crude oil reserves
31.Which of the following are problems associated with sending plastic bottles to landfill? (Select all that apply)
Medium
- AThey take up space at landfill sites
- BThey are not biodegradable and persist for a long time
- CThey release large amounts of carbon dioxide as they decompose
- DThey can be recycled instead to conserve raw materials
- EThey cause acid rain directly
32.Reusing a glass bottle saves more energy than recycling it.
Easy
True or false?
33.An abbreviated life cycle assessment used in advertising always gives the complete picture of a product's environmental impact.
Easy
True or false?
34.Which of the following is the correct order of the four main stages of a life cycle assessment (LCA) for a product?
Easy
- ARaw materials, manufacture, usage, disposal
- BManufacture, raw materials, disposal, usage
- CUsage, disposal, raw materials, manufacture
- DDisposal, usage, manufacture, raw materials
35.A life cycle assessment only considers the environmental impact of a product during its disposal stage.
Easy
True or false?
36.Which of the following are environmental impacts that can occur during the raw materials stage of a life cycle assessment? (Select all that apply)
Medium
- AUsing up limited resources such as ores and crude oil
- BDamaging habitats through deforestation or mining
- CUsing up land for factories
- DProduction of waste
- EUsing up space at landfill sites
37.Which of the following is an environmental impact of the manufacturing stage of a product's life cycle?
Medium
- AUsing up land for factories
- BUsing up limited resources such as ores
- CDamaging habitats through deforestation
- DUsing up space at landfill sites
38.A company publishes an LCA in an advertisement that only shows the benefits of its product and ignores any negative environmental impacts. What is this an example of?
Medium
- AA selective or abbreviated LCA used to support a pre-determined conclusion
- BA complete and fully objective LCA
- CA comparative LCA that compares two products fairly
- DA quantitative LCA using only measured data
39.In a comparative life cycle assessment of plastic and paper shopping bags, which of the following is a reason why the plastic bag may be considered the better option overall?
Medium
- AIt has a much longer lifespan because it can be reused many times.
- BIt is biodegradable and non-toxic.
- CIt is made from a renewable raw material.
- DIt produces no pollution when recycled.
40.In a comparative life cycle assessment of plastic and paper shopping bags, which of the following is an advantage of using paper bags instead of plastic bags?
Medium
- APaper bags are biodegradable and non-toxic.
- BPaper bags are made from crude oil, a finite resource.
- CMaking paper bags uses less energy than making plastic bags.
- DPaper bags can be reused many times.
41.What is the name of the monomer that poly(ethene) is made from?
Easy
42.A plastic bag has a mass of 6 g and a paper bag has a mass of 55 g. How many times heavier is the paper bag than the plastic bag? Give your answer to 1 decimal place.
Medium
43.Complete the sentence about recycling glass.
Easy
Glass that cannot be reused is separated by ____ and composition before being crushed and melted.
44.Complete the sentence about reusing glass bottles.
Easy
Glass bottles can be reused because they only need to be ____ and ____ before they are used again.
45.Name the process by which glass that cannot be reused is recycled.
Medium
46.A life cycle assessment compares two types of bag. The plastic bag produces 40 g of CO₂ per bag and the paper bag produces 70 g of CO₂ per bag. If 1000 bags of each type are used, what is the difference in total CO₂ emissions in kilograms?
Medium
47.Complete the sentence about a life cycle assessment.
Easy
A life cycle assessment (LCA) analyses the overall ____ that a product may have throughout its lifetime.
48.Complete the sentence about obtaining raw materials.
Easy
Obtaining raw materials can damage habitats through ____ or mining.
49.Complete the sentence about manufacturing.
Medium
Manufacturing processes use fossil-fuelled machines for ____ and transport.
50.Complete the sentence about disposal.
Medium
Disposal of outdated products uses up space at ____ sites.
51.Complete the sentence about LCA objectivity.
Medium
Allocating numerical values to pollutant effects is less straightforward and requires value ____.
52.Complete the sentence about comparative LCAs.
Medium
An LCA can be carried out on plastic and paper shopping ____.
53.Explain why a life cycle assessment may be biased or misleading.
Hard
54.Give three reasons why a steel car body should be recycled rather than being sent to landfill.
Hard
55.A plastic bag has a mass of 6 g and a paper bag has a mass of 55 g. How many times heavier is the paper bag than the plastic bag? Give your answer to 1 decimal place.
Medium
- A11.2
- B9.2
- C8.2
- D10.2
56.A life cycle assessment compares two types of bag. The plastic bag produces 40 g of CO₂ per bag and the paper bag produces 70 g of CO₂ per bag. If 1000 bags of each type are used, what is the difference in total CO₂ emissions in kilograms?
Medium
- A33 kg
- B27 kg
- C36 kg
- D30 kg

Karteikarten

What is a life cycle assessment (LCA)?

An analysis of the overall environmental impact a product has throughout its lifetime, from raw materials to disposal.

What are the four main stages of a life cycle assessment?

Raw materials, manufacture, usage, and disposal.

Give two environmental impacts of obtaining raw materials for a product.

Using up limited resources such as ores and crude oil, and damaging habitats through deforestation or mining.

Give two ways that manufacturing a product can harm the environment.

Using up land for factories, and using fossil-fuelled machines for production and transport (which also produces waste).

Why does the usage stage of an LCA vary in importance between products?

It depends on the product: a wooden desk has very little impact during use, whereas a car has a significant impact, such as air pollution.

Give two environmental impacts of disposing of a product.

Using up space at landfill sites, and whether the product or its parts can be recycled.

Which parts of an LCA are easy to quantify, and which are not?

Amounts such as water used or waste produced are easily quantified; pollutant effects are hard to give a numerical value to.

Why is an LCA not a purely objective process?

Allocating numerical values to pollutant effects requires value judgements, so different people may give different values or be biased.

Why can an abbreviated or selective LCA be misleading?

It does not give the complete picture, so it can be used in advertising to highlight environmental benefits while hiding negative impacts.

Why is there rarely a perfect product with zero environmental impact?

Almost every product has some impact, so a compromise is usually made between environmental impact and economic factors.

What raw material are polymers such as poly(ethene) and poly(propene) made from?

Crude oil, which is a finite (non-renewable) resource.

What is the monomer that poly(ethene) is made from?

Ethene.

Give two problems with sending plastic bottles to landfill.

They take up space at landfill sites and they are not biodegradable, so they remain there for a long time.

Give two problems with recycling plastic bottles.

Collection and sorting require energy and labour, and the process can be costly and produce pollution.

Classify the raw materials for plastic and paper bags as renewable or non-renewable.

Plastic bags: crude oil, which is non-renewable. Paper bags: trees or recycled paper, which are renewable.

Give two reasons why paper bags may be preferable to plastic bags.

They are biodegradable and non-toxic, and they can be made from recycled paper or trees, which are renewable.

Give two reasons why plastic bags may be preferable to paper bags.

They are cheaper to make, use less energy in manufacture, and are reusable many times, giving them a longer lifespan.

Why can a plastic bag be considered the better option overall in a comparative LCA?

Although not biodegradable, plastic bags have a much longer lifespan and are reusable many times, so they can be less harmful than paper bags.

How does the way a bag is used affect which bag is better for the environment?

If the paper bag is recycled it could be more favourable; if the plastic bag is used only once, the argument for plastic becomes less favourable.

Why should aluminium be recycled?

To reduce the amount of waste and to conserve raw materials (it is also much more energy efficient than extracting it).

Why is it economically beneficial to recycle metals such as aluminium?

Metals that are costly to extract, like aluminium, are worth recovering, and recycling is a major industry that provides employment.

Give two environmental advantages of recycling metals.

Less mining is required, so fewer CO₂ and greenhouse gas emissions are released; and melting and remoulding uses less energy than extraction.

How does recycling reduce the impact on landfill?

It decreases the amount of waste produced, so less space is needed at landfill sites.

Give two disadvantages of recycling.

Collection and transport require energy and fuel, and materials must be sorted, which needs energy and labour; recycled products may also be of lower quality.

How can glass bottles be reused rather than recycled?

They only need to be washed and sterilised before being used again, which saves energy and reduces environmental impact.

How is glass recycled?

Broken or damaged glass is separated by colour and composition, then crushed, melted and remoulded into new shapes.

How is scrap steel used in steel making to reduce resource use?

Scrap steel is added to iron from a blast furnace, which reduces the amount of iron that needs to be extracted from iron ore.

Why is effective recycling important as global populations increase?

There is a limited supply of every material on Earth, so recycling is needed to attain sustainable development.

What is the difference between reusing and recycling a product?

Reusing uses the product again directly, such as washing a glass bottle; recycling processes the material into a new product.

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