Could your air conditioning unit catch a criminal? Scientists say yes.
It’s common in criminal investigations to collect trace amounts of DNA—comprising just a few human cells—from crime scenes. Already, samples taken from surrounding surfaces, soil and water are used to collect evidence. But according to new research from Flinders University in Australia, forensic scientists could also start collecting DNA data from thin air.
“Human DNA can be found in the air after people have spoken or breathed (via saliva droplets), shed skin cells or dislodged and aerosolized from surfaces and collected for DNA analysis,” Emily Bibbo, a Ph.D. candidate at Flinders University’s College of Science and Engineering and co-author of the study, said in a statement.
“We may be able to use this as evidence to prove if someone has been in the room, even if they wore gloves or wiped surfaces clean to remove the evidence.”
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In a study published in the journal Electrophoresis, the Flinders team, led by Senior Forensic Science Lecturer Mariya Goray, investigated how air conditioning units and air filters could be used to sample the air at the scene of a crime to identify both the usual users of a room as well as any visitors.
“It is very unlikely that an average offender, even with forensic awareness, could totally prevent their DNA from being released into the environment,” Goray said in a statement.
The small-scale study compared samples taken from four offices and four houses at different time points after cleaning. They also investigated how effective common air filters were at collecting DNA data from their surrounding environment.
Their results clearly demonstrate that human DNA can be collected on the surfaces of air-conditioner units as well as from the air. And while air samples are more likely to represent the most recent occupants of a room, particles that have settled on the surface of air conditioning units can give more information about the room’s previous occupants.
Based on this data, the team recommends follow-up studies to optimize the process of DNA collection and testing from these surfaces, as well as the optimal positioning for air conditioning units within a space. Even so, this preliminary research demonstrates the exciting potential of air conditioning units and air filters in aiding in criminal investigations.
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Uncommon Knowledge
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Newsweek is committed to challenging conventional wisdom and finding connections in the search for common ground.