You could be experiencing an allergic reaction to your car air freshener, says Daniel Swartz, executive director of the Children’s Environmental Health Network, a nonprofit Washington, D.C.-based consumer safety organization. Conventional car fresheners contain troublesome chemicals like petroleum distillates, which can irritate or damage your lungs; phthalates, which can interfere with hormone production; and benzene compounds, which have been found to be carcinogenic.

… How to create a air freshener for your car I just took an old sock (or actually two of them) and put one inside the other and filled it up with a bit of baking soda.