Active air vs. passive air (settle plate) monitoring in routine environmental monitoring programs.

This article discusses the utility of active air versus passive air settle plate monitoring in a routine environmental monitoring program with an emphasis on the monitoring of the critical Grade A environments. It is recognized that there has been a long-standing historical use of settle plates in the pharmaceutical industry, and that European regulatory agencies have supported their use. However, current active air sampling technology can be more advantageous and effective in assessing airborne viable contamination in cleanrooms than settle plate monitoring. Given that both methods are designed to assess viable airborne contamination in cleanrooms, there may be no advantage in performing these two parallel methods for the detection of airborne contamination, especially if doing so increases the number of interventions into critical areas, which may in turn increase the risk of contamination without providing any added benefit in terms of data collection and/or process control. Therefore, the best use of settle plate monitoring may be as an optional test method for those applications where other, more efficient sampling methods may not be possible or may have limited applicability.