Life Cycle Analysis is a way to look at all environmental impacts of a certain product or application over its entire life-span. You take into account all the environmental impacts of mining for metals, drilling for oil, transporting ores, and you can even discern between scarce and abundant materials. Then you measure the impact of making half products and the final products in factories (including the energy used for all that), and calculate all the environmental impacts during the use of the product. Finally you take into account the environmental impact of discarding the products.
With this method, abbreviated to LCA, you can compare two products that deliver the same service, such as two different cars. You compare them on total toxic materials emitted into the environment, greenhouse gas emissions, total energy use per driven km, etc. You can correct for number of km’s driven or lifetime of the car. You can also calculate the effect of recycling (e.g. if recycled aluminium is used in producing your car, the environmental impact of the car is lowered; and for other products it may even be so that if you could use it twice, you already half the environmental impact). You can thus calculate where you can change the materials used or production method used to lower the impact.
Since the use of nano particles may have advantages, such as higher quality of a product, reduced energy use, etc, it would be interesting to see how the use of nano-particles compares to alternatives, e.g. through an LCA. Since learning how to perform an LCA is one of the competences for students in environmental studies, we think that questions like these should be suitable for student-research.
The fact that not all environmental impacts of nano-particles are known yet, complicates matters and puts a challenge on methodological refinement of the LCA method. In general, nano-particles behave different from larger particles. This gives them the special properties that makes them well suited for certain applications. However, it also makes them behave differently in the environment and body. Nano-particles have a relatively large surface per weight unit. Since reactions occur on the surface, they are much more reactive than larger particles. Thus, environmental standards that are based on weight units are not suitable to control nano-sized particles of a certain substance. However, nano-particles can be firmly attached to a matrix and when they do not become free, they can not enter the environment as nanoparticles. All these aspects need to be taken into account when studying environmental impacts of nano-particles.
We would gladly open the floor to discuss the use of LCA for nano-particle applications. Which other issues do you have where an LCA study could be of help to clarify the pros and cons, and alternatives?