Environmental monitoring ensures the controlled manufacturing environment remains compliant with USP <1116>, EU GMP Annex 1, and ISO 14644 requirements. Monitoring programs include active air sampling, passive settle plates, contact plates, and surface swabbing to detect viable contaminants. Data trending against alert and action limits supports proactive contamination control and sterility assurance in aseptic processing. This testing is critical for demonstrating the ongoing suitability of cleanroom operations.