Investigations into environmental monitoring (EM) excursions can be prolonged and do not always result in clear root causes or CAPAs. This paper outlines how bio-fluorescent particle counting (BFPC) can be used in investigations to eliminate the inherent delays of culture-based methods. The application for investigations supplements routine EM; acting as a risk reduction tool enabling real-time detection of viable microorganisms in air samples − supporting root cause analysis and remedial actions. The paper includes guidance on how to use the technology, a real case study involving a mold excursion, and examples of business benefits achieved by various companies.