AUSTRALIA: In the future, air conditioners could be used by forensic scientists to access crucial DNA evidence when solving crimes.

A new study by researchers at Flinders University in Adelaide is exploring new methods to potentially collect and record key DNA evidence obtained through aerial forensics from crime scenes cleared of fingerprints and other traces.

“Human DNA can be detected in the air after people have spoken or breathed (through droplets of saliva), shed skin cells, or been dislodged and dispersed from surfaces and collected for DNA analysis,” explained Emily Bibbo, a PhD candidate at Flinders University College of Science . and engineering.

“We may be able to use this as evidence to prove whether someone was in the room, even if they were wearing gloves or wiping surfaces clean to remove evidence.”

Collecting DNA traces involving just a few human cells is commonly used in criminal investigations, but success rates in collecting this type of evidence remain low, researchers say.

However, new technologies are opening up new opportunities for collecting evidence, including the emerging field of environmental DNA (eDNA) from solid surfaces, soil, water and air.

The pilot study, conducted in collaboration with international experts, focused on additional DNA collection capabilities by studying air conditioners as well as different types of filters over different time periods to compare results.

Flinders University senior lecturer in criminology Dr Maria Gorai says biological material is routinely collected from crime scenes and exhibits and these new methods could help identify normal room users as well as visitors.

“It is very unlikely that the average criminal, even with forensic knowledge, will be able to completely prevent his DNA from being released into the environment,” Dr Goray said.

A small pilot project compared the results of samples taken from air conditioning units in four offices and four homes at different times after cleaning. Another study examined the feasibility of collecting human DNA from indoor air, with and without people present, for different periods of time and using different types of collection filters.

Research findings suggest that human DNA can be collected on air conditioner surfaces and in the air, with air samples likely reflecting more recent occupation while previous indoor occupants were more common in air conditioners.