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A stock-and-flow version of the co-effects structure of Figure 6. The graphical conventions are those defined for Figure 1. The double-lined, double-ended arrows are “bi-flows” representing net processes that can drive the levels of their affected stocks up (inflow) or down (outflow). The variables labelled Public Health Difference and Air Quality Difference represent the difference between the actual level of the controlled variables and their respective goals.
