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Index of Environmental Assessment

There are two kinds of indexes for the environmental assessment. Those are total amount and ratio. Both of them have strong point and weak point.

Index based on total amount

For example, it is the amount of input and output of chemical substances in a factory.

• Strong : We can evaluate the effect to the environment directly.
• Weak : Large improvement in small factory is not looks tiny thing to compare a large factory.

Index based on ratio

Density of chemical substances and the basic unit of CO2 are examples.

Correlation is considered when we use this index.

• Strong : Control of output is easier. There are measurement instruments. And the size of factories not affect.
• Weak : With much water, the value of this density seems to be small.

Eco Efficiency

Eco efficient has some definitions. For example, "Output / Input".

WBCSD (World Business Council for Sustainable Development) suggests the criterion for Eco Efficiency.

Factor

As eco efficiency, there is a definition,
"Value / Environmental-Impact".
The dimension of this index is not zero because dimensions of the numerator and the denominator are different.

Factor is defined
"Eco efficiency of the target / Eco efficient of the standard".
Factor is zero dimension.

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