Forensic science researchers have developed a new technique for capturing airborne DNA at crime scenes.

The innovative method could revolutionise forensic investigations.

“Human DNA can be found in the air after people have spoken or breathed (via saliva droplets), shed skin cells, or dislodged and aerosolised from surfaces and collected for DNA analysis,” says Emily Bibbo, a PhD candidate at Flinders University.

This could prove someone's presence in a room, regardless of attempts to remove other forms of evidence.

Despite the common use of trace DNA in criminal investigations, success rates have been low. This new approach, part of the burgeoning field of environmental DNA (eDNA) detection, aims to improve evidence collection by detecting human DNA in air and on surfaces.

The method has been tested using standard air-conditioning units and a portable air collection device common in detecting airborne viruses. Findings suggest that while DNA can indeed be collected from the air, optimising collection methods and timings post-crime remains a challenge. 

The study, a collaboration between Flinders University, Forensic Science SA and the Victoria Police Forensic Services Department, examined air-conditioner units and different filters over various periods to gauge DNA collection effectiveness. 

The full paper is accessible here.