Gas Engine Emissions for Drilling Application

I am searching for information on how emissions vary with air/fuel ratio (i.e., lambda) for natural gas engines ranging from rich burning to lean burning.  As it turns out, Figure 2 in the CAT Publication LEBW4984-01, “Gas Engine Emissions”, seems to maybe have the information I am looking for.  My problem is that for the version of the publication that I have found online, that figure is not legible.


Does anyone have a completely readable version of this document and specifically that figure?