ppolx: Persistent Pollution Index
Variable
Persistent pollution sector
Persistent Pollution Index [Dmnl]
ppolx = ppol / ppol70

ppolx in the updating graph: ( how to read )
In nodes
ppol : Persistent Pollution
ppol70 : persistent pollution in 1970
Out nodes
ahlm : assimilation half life multiplier
lfdr : land fertility degredation rate
lmp : lifetime multiplier from persistent pollution
pptcm : persistent pollution technology change multiplier