Newer filtration efficiency standards published by ASHRAE are becoming the industry standard for testing filtration efficiency.  ASHRAE standard 52.2-1999 test results are expressed as a MERV (Minimum Efficiency Rating Value) Rating.  Understanding filtration efficiency and MERV ratings is important in thermal spray, since much of the dust generated is very small, even sub-micron.  This is especially important with the new standards for clean air like those published by the California Air Resources Board (CARB).  This presentation will describe how MERV Ratings apply to thermal spray processes so that you can choose filtration that will dramatically improve air cleanliness for employees, business, and the environment.