The decipol is a unit used to measure the perceived air quality.
[1] It was introduced by Danish professor P. Ole Fanger.
One decipol (dp) is the perceived air quality (PAQ) in a space with a sensory load of one olf (one standard person) ventilated by 10 L/s.
It was developed to quantify how the strength of indoor pollution sources indoors influence air quality as it is perceived by humans.
[1]