ΔE 12.7, fair: the same colour family, but not a straight swap. Dirty Grey is a little lighter, cooler than Green Ochre.
Only where an exact match doesn’t matter, such as a new unit or a highlight. Fair match (ΔE 13). Dirty Grey is a little lighter, cooler than Green Ochre.
The same difference applies the other way round: Green Ochre is a little darker, warmer.
ΔE is the colour difference between our two swatch estimates: under about 6 is close, over about 15 is loose. Real paints also differ in finish, coverage and how they thin, so test before you commit.
See Green Ochre on the colour wheel See Dirty Grey on the colour wheel
All matches: Green Ochre equivalents · Dirty Grey equivalents