One of the number 1 things that I tell my clients when they are setting their home up to sell is to rid themselves of their plug-in air fresheners and opt for natural alternatives. The reason for this is that guests walking into your home, if overwhelmed by the artificial scent, may assume that the air freshener is there to "hide" something else. The other reason however is simply that they're not healthy for you and your family. As a natural alternative, I suggest baking a sliced lemon in the over, or fill a baking pan with about a 1/2" of water, and place orange slices and cinnamon powder in the water. Bake in the oven at 350 degrees for approximately 20 minutes. Your home will smell like fresh baking, a warm inviting scent.
For more information as to how bad your air fresheners are, please read the attached article: