Ammonia Smelling Odors From the Ducts and Vents

Ammonia Outside

• Ammonia exists naturally in the air outside but typically not in high enough concentrations that it is detectable by scent alone. One of the common reasons people detect an ammonia smell outside the home is due to rainfall; rain absorbs ammonia in the air, and it travels with the rain. Therefore, soil, rain gutters, storm runoff drains and any other area that collects large volumes of rainfall can produce an ammonia odor since the rain carries the ammonia with it.

Possible Dangers

• Like hydrogen sulfide and other harmful gases, ammonia has a very strong odor at even very low concentrations, so exposure at dangerous levels is unlikely since ammonia is so easily detectable. But ammonia gas exposure at high levels can cause severe burns of the skin and eyes, lung damage and even death. At lower concentrations, those with chronic respiratory ailments, such an asthma, can experience irritation of their symptoms. Water imparted with small concentrations of ammonia can cause fish death and is harmful to humans that consume it in large concentrations.

What To Do

• If the ammonia smell is outside of your home, it is best to stay inside, seal all doors and windows and turn off central air conditioning and heating systems. If there is a strong ammonia odor inside your home as well, go outside; in either case, dial 911 right away and follow the instructions given to you by the operator. If the odor is present both indoors and out, travel to an area where the smell is not persistent before calling 911.

Other Considerations

• Though less common, there are several possible sources of an ammonia odor other than rainfall. If you live near an agricultural or industrial facility, an ammonia spill or other accident may impart a strong ammonia odor to the air. Runoff due to excessive use of ammonia fertilizers can also contribute to a detectable ammonia odor.