Questions: Environmental Impact of Engineering

Question 1

A lifecycle assessment (LCA) evaluates environmental impact at which stages?

• A. Only during manufacturing
• B. Only during use by the consumer
• C. From raw material extraction through disposal or recycling
• D. Only during disposal

Answer: (C)

LCA covers the entire lifecycle: raw material extraction, material processing, manufacturing, transportation, use, and end-of-life (disposal or recycling). This 'cradle-to-grave' approach reveals impacts that would be hidden by looking at only one stage.

Question 2

A paper bag is typically more environmentally friendly than a plastic bag.

• T. True
• F. False

Answer: False

Paper bags require more energy and water to manufacture, produce more air pollution during production, and are heavier to transport than plastic bags. A paper bag must be reused 3-4 times to match the per-use impact of a single-use plastic bag. The 'better' choice depends on which environmental impacts you prioritize and how many times each bag is used.

Question 3

What does 'design for disassembly' mean and why is it important for environmental impact?

Model answer: Design for disassembly means engineering a product so that it can be easily taken apart at end-of-life, allowing different materials to be separated for recycling or reuse. Products that mix materials inseparably (glued composites, encapsulated electronics) are difficult or impossible to recycle, so their materials end up in landfills.

If a smartphone's battery could be easily removed, the battery could be recycled separately from the circuit board and screen, each through appropriate processes. When components are glued, fused, or potted together, the entire assembly often goes to waste. Design for disassembly is an engineering decision made at the design stage that dramatically affects end-of-life environmental impact.