Accession Number:



Mechanical Details for Construction of a Dry Aerosol Deposition Device

Descriptive Note:

Technical paper

Corporate Author:


Personal Author(s):

Report Date:


Pagination or Media Count:



This document contains detailed design information for assembly of a Dry Aerosol Deposition Device DADD. This report is further to technical report AFRL-RX-TY-TP-2008-4617, ADA492108 and technical report AFRL-RX-TY-TR-2008-4592, ADA502105 work unit DODT0056. Growing threats of biological contamination of infrastructure and equipment led to the development of antimicrobial surfacescoatings. Standard methods to test efficacy of such materials have applied microbial agents suspended in aqueous buffers. These surfaces, however, will likely be contaminated via aerosol exposure, so antimicrobial efficacy measurements using microbes deposited as aerosols will provide a more-representative test platform. A settling chamber is the most common method for depositing biological aerosols on surfaces, but it can impose limitations in respect to time and variability of sample loading. In prior work, a Dry Aerosol Deposition Device DADD was developed that uses impaction rather than settling to load surfaces with biological aerosols, providing a mechanism for rapid and highly reproducible loading of microorganisms onto surfaces. The DADD was tested with Bacillus atrophaeus spores and Staphylococcus aureus vegetative cells, deposited to glass coupons at concentrations exceeding 1 104 colony-forming unitscm2. The average coefficient of variation CV for sample-to-sample loading within experiments was 13.6 for spores and 6.1 for S. aureus cells. The DADD provides a mechanism to load coupons with a highly reproducible challenge of microorganisms. Preliminary validation was performed on glass coupons, but the device can also be used with aluminum, concrete or fabric samples. The DADD was demonstrated to be a relatively simple and inexpensive device that can easily be contained within a 4-foot biological safety cabinet.1

Subject Categories:

  • Microbiology
  • Machinery and Tools
  • Chemical, Biological and Radiological Warfare

Distribution Statement: