ACE-IT Air cleaner efficacy investigation tool The air cleaner efficacy investigation tool (ACE IT) is a spreadsheet application designed to support you in translating air cleaner performance data of the type (X% reduction in Y hours) to a clean air delivery rate. Instructions for use are present in the "overview" tab of the spreadsheet. Most up to date version (v1.2) (view only) Download a copy of v1.2 Other resources/relevant information: Blog post by Dr. Brent Stephens at IIT showing examples of these types of calculations. Open letter written, signed/supported by the developers of ACE-IT concerning additive air cleaners Prior versions: Click here for v.1.1 Click here for v1.0