You can find all manner of things to freshen the air in your home but most have downsides — plug-in air fresheners are filled with chemicals, candles can burn your house down. Reed-based air fresheners are chemical and flame free.
If you've never seen a reed-based air freshener at a home store or boutique, the premise is straight forward. A handful of reeds is placed into a bottle of carrier oil with a scent oil added to it. The capillary action of the reeds pulls the oils up through the reed and the oil is slowly diffused into the air.
It requires no electricity, the carrier oil and scent oil can be as simple and natural as almond oil with an essential oil like mint or lavender added, and no flame means no fire hazard. At the home-centric blog TipNut they have a guide to putting together your own reed diffuser. Check out the full tutorial at TipNut for additional information and tips on the kinds of oils you can use in your diffuser.