Model Spot Sampler -Aerosol Particle Collector

Aerosol is sampled through a wet walled tube, the middle section of which is warm

1. In the first, Conditioner section, the flow is cooled and humidified.
2. In the warm-walled Initiator section, water evaporates from the wet walls faster than the flow warms. The flow becomes supersaturated, initiating the condensational growth of particles >5nm.
3. In the final, Moderator section, heat and water vapor are removed from the flow while maintaining supersaturated conditions that allow continued growth to form ~3µm droplets.
4. The droplets are collected by impaction, and warmed to make a concentrated, dry spot. Collection into liquid is also possible.

Samples are collected as a sequence of ~1-mm diameter dry spots on a multiwall plate. Upon return to the laboratory, the plate is placed on an auto-sampler which handles all the sample extraction and HPLC or IC injection. Concentrated spots are also amenable to many analytical approaches, such as nano-DESI and LIBS, etc.