Mark Hallworth is the Life Sciences Global Manager and Senior GMP Advisor at Particle Measuring Systems. Over Mark’s long career in contamination control, he has managed the design, installation, and validation of over 200 environmental monitoring system projects worldwide. He has designed several products specific for pharmaceutical environmental monitoring, including particle counters for explosive and corrosive areas and 21 CFR part 11 compliant software for batch test and release. He currently lectures for the PDA, ISPE, and other international pharmaceutical societies on environmental monitoring and GMP compliance design and validation. Mark has written over 100 technical papers on environmental monitoring and contributed to several books specific to this field. Most recently, Mark was a member of the international ISO 14644-21 technical committee responsible for reviewing and revising the standard. He was awarded the IEST James Mildon award for “significant contributions to the advancement and increase of knowledge in the field of contamination control”.