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P144 – When Air Moves, DNA Travels: Investigating Airborne Human DNA in Undisturbed and Disturbed Intruded Spaces
With increased sensitivity in DNA detection, a wider range of evidentiary samples can now yield informative DNA profiles. However, challenges remain when generating profiles from trace and touch DNA samples, largely due to the inability to visualise optimal sampling locations and the deliberate removal of contact traces by forensically aware perpetrators. Environmental DNA (eDNA) which focuses on the detection of genetic material shed by organisms into their environment, presents a novel approach to overcoming these limitations. While its utility has been widely explored in species identification, its application in forensic investigations remains in early stages. A key development in this area is the recovery of human DNA from the air, representing a novel and potentially valuable source of forensic evidence. This study aimed to investigate the extent to which intruders can be detected in air samples following a simulated burglary and to assess whether air disturbance enhances overall DNA detectability. Air samples were collected from pre-occupied households under two post-intrusion conditions: before disturbance and during disturbance. With the use of an AirPrep ACD220 electret filter sampler, air was drawn through electret filters, and the recovered DNA was analysed with respect to the identities of regular household occupants and intruders. The findings demonstrated that DNA can be recovered from indoor air both with and without agitation. Notably, air disturbance increased overall DNA recovery and detection of regular and past occupants; however, recent intruders were detected less frequently, despite confirmed interactions with a number of objects and surfaces. These results provide valuable insight into the utility and conditions of air sampling for human DNA in forensic contexts. These results also highlight the importance of managing airborne contamination risks and suggest that air collection could serve as a useful supplement to traditional environmental monitoring in forensic laboratories, where it may assist in evaluating the effectiveness of cleaning and contamination minimisation protocols following further research and validation.
Authors
- Emily Bibbo (College of Science and Engineering, Flinders University, Australia)
- Duncan Taylor (Forensic Science SA, Australia)
- Roland van Oorschot (Office of Chief Forensic Scientist, Victoria Police Forensic Services Department, Australia)
- Mariya Goray (College of Science and Engineering, Flinders University, Australia)
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