Why is there a electrical burning smell coming through the vents in my car??

Hello Subie family. I have a 2007 Subaru Outback 2.5L SOHC, my question is
about smells. For about a week now I have been experiencing a burning type
smell coming through vents of my car. This smell only occurs say after I've
been driving for a little and i happen to stop at a red light and/OR idling waiting
and that's when this smell starts.  My passenger says it smells electrical. I do
know a little about cars well at least my own car. But this burning smell has me
stumped. Does anyone in the Subie family have an idea on what this burning
smell is and if so PLEASE SHARE YOUR INSIGHT/INFO.  WHAT, WHERE and
HOW to fix.
PLEASE and THANK YOU
Tia S.,
Spokane Valley,  WA