Logarithmic Scale Conversion

[Pero]

Hello people.

So I'm trying to figure this out:
here is a sensitivity characteristics of my gas sensor, and the both x and y scales are logarithmic.

Now, i'd like to interpolate this data but I guess I can not use simple linear method, like y=(y2-y1)/(x2-x1)*x+y1. What do you think?

Regards,

Pero