Fungi, bacteria and dust accumulation in the ventilation ducts of large office buildings is the main reason for the deterioration of the same. Such buildings can now be nursed back to good health thanks to a treatment offered by Prime Clean, a Swedish company, and the Royal Technical University in Stockholm. To clean the ducts, rotating brushes and compressed air are used.

The cleaning nozzle makes about 15,000 to 20,000 revolutions per minute, thus loosening the dirt. When the nozzle is pulled back, the compressed air blows out the dirt from the ducts, leaving behind a clean ventilation system.