6.2. QA CMAQ# Quality Assurance: Comparing the output of two CMAQ runs. 6.2.1. Quality Assurance 6.2.2. Run m3diff to compare the output data for two runs that have different values for NPCOL 6.2.3. Use m3diff to compare two runs that have the same NPCOL 6.2.4. Run an R script to create the box plots and spatial plots comparing the output of two runs