L51483 Evaluation of EPA Method 20 Ambient Correction Procedure

Addresses the effects of the current EPA Method 20 correction factors on predicted NOx levels vs. actual observed NOx emissions based upon data from some 800 engine field test data sets. The report demonstrates that correction procedure to the 85 degrees F / 75 grains of water per pound of dry air standard introduces considerable over-prediction and presents a case for the elimination of the procedure or at a minimum a modification to permit regional correction factors. The data sets are displayed in Appendix of some 200 p.