When people refer to “smelling salt,” they typically mean ammonia inhalants, a chemical compound. This term often causes confusion with literal table salt (sodium chloride), which has vastly different effects. This article focuses on the physiological impact and safety considerations of ammonia-based inhalants, and explains why table salt is odorless.
Understanding Ammonia Inhalants
Ammonia inhalants are chemical preparations primarily composed of ammonium carbonate. Many modern formulations also consist of a dilute solution of ammonia dissolved in a mixture of water and ethanol. These substances are commonly packaged in crushable ampules or small capsules.
Historically, these inhalants, sometimes called “spirit of hartshorn,” were used as early as Roman times and gained widespread popularity in Victorian England to revive individuals who had fainted. In contemporary settings, ammonia inhalants are frequently seen in sports, where athletes use them to enhance alertness and focus.
How Ammonia Inhalants Affect the Body
The stimulating effect of ammonia inhalants stems from the release of ammonia gas. When inhaled, this pungent gas irritates the mucous membranes lining the nose and lungs, activating the trigeminal nerve.
This nerve stimulation sends signals to the brainstem, triggering an involuntary gasp reflex. This causes a rapid increase in breathing rate and depth. The body’s sympathetic nervous system responds with a “fight or flight” reaction, leading to a temporary rise in heart rate and the release of adrenaline. These responses contribute to immediate heightened alertness, increased focus, and temporary relief from lightheadedness.
Safe Use and Potential Risks
Ammonia inhalants can provide a temporary boost, but their use requires consideration. Proper application involves holding the product away from the nose, typically 10 to 15 centimeters, to limit direct exposure to high concentrations of ammonia gas. This helps prevent chemical burns.
Improper or excessive use of ammonia inhalants carries several risks. Direct contact can cause chemical burns to the nasal or oral mucosa, and prolonged inhalation may damage the respiratory tract. Side effects can include headaches, coughing, and respiratory distress. Individuals with pre-existing respiratory conditions such as asthma or bronchitis may experience worsened symptoms.
Medical and sports organizations advise against their use in cases of suspected head injuries or concussions, as the induced alertness could mask more serious neurological symptoms and potentially delay proper diagnosis and treatment. The involuntary withdrawal reflex could also exacerbate neck or spine injuries. The FDA has also issued warnings against unapproved inhalant products marketed for alertness and energy.
Why Table Salt is Odorless
Table salt, chemically known as sodium chloride (NaCl), is an ionic compound. Its structure consists of a crystal lattice where sodium and chloride ions are held by strong electrostatic bonds. These robust bonds mean very few sodium chloride molecules become airborne at room temperature.
Our sense of smell detects volatile compounds, which evaporate and release molecules into the air. Since sodium chloride has extremely low volatility, it does not release a sufficient amount of airborne molecules for us to perceive an odor. While pure table salt is odorless, any faint scent detected might be attributed to impurities, moisture, or other compounds present in less refined salt products, rather than the sodium chloride itself.