Protocol to Perform Source Apportionment on ACSM Data Using SoFi Pro

The Standard Protocol for ACSM/AMS PMF Analysis describes a standardized workflow for applying Positive Matrix Factorization (PMF) to aerosol mass spectrometry (AMS) and Aerosol Chemical Speciation Monitor (ACSM) datasets. It outlines the recommended procedures for data preparation, quality assurance, PMF model configuration, evaluation of solution stability, and interpretation of factor profiles and time series. The protocol also defines a set of diagnostics and reporting practices, including assessments of residuals, rotational ambiguity, bootstrapping, and comparisons with external tracers, to promote consistent analysis and facilitate the comparison of PMF results across studies and research groups.