Oxygen drop conversion to PPM review:

A short cut method that can be used to quickly determine oxygen sensor drop to PPM:

For each 1/10th of a percent (the smallest the oxygen sensor can read) there is a 5,000 PPM corresponding drop.

Summary:

0.1% O2 drop = 5,000 PPM

0.2% O2 drop = 10,000 PPM

0.3% O2 drop = 15,000 PPM

0.4% O2 drop = 20,000 PPM