Particle Measuring Systems’ newest Airborne Molecular Contamination (AMC) monitor, the AirSentry® II, was designed with performance in mind. The new Ion Mobility Spectrometry (IMS) cell provides ppt sensitivity, fast response, and increased selectivity. Continuous coverage of a critical monitoring point and a central software platform allow for easy data acquisition and analysis. Maximizing the value of contamination information delivered, the AirSentry® II allows smarter decisions to be made for locating, controlling, and preventing molecular contamination. Current monitoring techniques, most evolving from a strategy of adapting old technology to contamination applications, are proving inadequate as critical dimensions shrink and lithography tools increase their exposure energy. Shortcomings such as lack of time resolution, sample transport contamination, and insufficient sensitivity have become glaringly apparent. Overcoming these inadequacies, the AirSentry® II continuously monitors a critical point with the highest sensitivity offered in a low cost, point-of-use AMC monitor.