I have two room that are spare bedrooms that sometimes stay closed for 2 weeks.  I don't  like using air freshner  and when opened up the rooms  needed windows opened.  Purchased two of these in white and plugged them in, shut the door the opened up 1 week later...WOW... fresh clean air.  LOVE IT!!!  Will be getting more for laundry room & near the garbage. 

Pros: EASY