Ammonia (NH3) is a colorless, caustic gas with a pungent odor that is used in many industries and applications. It is also known as anhydrous ammonia. Ammonia (NH3) stands as one of the most frequently manufactured industrial chemicals. Its applications span various industries and commercial sectors, while also occurring naturally in both human biology and the environment. Vital for numerous biological processes, it acts as a precursor for synthesizing amino acids and nucleotides. In natural settings, ammonia plays a crucial role in the nitrogen cycle, generated in soil through bacterial activity. Additionally, it arises naturally from the decomposition of organic matter, encompassing plants, animals, and animal waste.
- At ambient temperature, ammonia manifests as a colorless, highly irritating gas with a distinctively pungent and suffocating odor.
- In its purest state, it is referred to as anhydrous ammonia, possessing hygroscopic properties (readily absorbing moisture).
- Exhibiting alkaline properties, ammonia is corrosive.
- Upon dissolving in water, it forms ammonium hydroxide, yielding a caustic solution and weak base.
- Ammonia gas readily compresses, transforming into a clear liquid under pressure.
- Typically transported as a compressed liquid in steel containers.
- Although not highly flammable, ammonia containers may explode under high heat exposure.
Approximately 80% of industrially produced ammonia serves as fertilizer in agricultural practices. Additionally, it finds application as a refrigerant gas, in water purification processes, and in the fabrication of plastics, explosives, textiles, pesticides, dyes, and various other chemicals. Household and industrial-strength cleaning solutions commonly contain ammonia. Household variants typically consist of 5 to 10% ammonia, produced by combining ammonia gas with water. Conversely, industrial-grade solutions may boast concentrations of 25% or higher and are inherently corrosive.
The primary route of exposure to ammonia for most individuals is through inhalation of its gas or vapors. Given its presence in both natural environments and cleaning agents, exposure may occur from various sources. Furthermore, the widespread utilization of ammonia in agricultural, industrial, and commercial settings elevates the risk of exposure, whether through accidental releases or deliberate acts of terrorism.
Anhydrous ammonia gas, being lighter than air, tends to ascend and dissipate, minimizing its accumulation in low-lying areas. However, in the presence of moisture, such as high relative humidity, liquefied anhydrous ammonia gas generates heavier-than-air vapors. These vapors have the potential to disperse along the ground or accumulate in poorly ventilated areas, increasing the likelihood of human exposure.
Upon contact with moisture in various bodily surfaces including the skin, eyes, oral cavity, and respiratory tract, ammonia undergoes immediate interaction to form the highly corrosive ammonium hydroxide. This compound leads to tissue necrosis by disrupting cell membrane lipids (saponification), ultimately resulting in cellular destruction. As cell proteins degrade, water is drawn out, triggering an inflammatory response that exacerbates the damage.
Inhalation: Ammonia proves both irritating and corrosive. High concentrations in the air swiftly lead to burning sensations in the nose, throat, and respiratory tract, potentially causing bronchiolar and alveolar edema, as well as airway destruction, which can result in respiratory distress or failure. Inhalation of lower concentrations may induce coughing, along with nose and throat irritation. While the characteristic odor of ammonia serves as an early warning of its presence, prolonged exposure at low concentrations can lead to olfactory fatigue or adaptation, diminishing awareness of continued exposure.
Children, when exposed to similar concentrations of ammonia vapor as adults, might incur a higher dose due to their greater lung surface area-to-body weight ratios and increased minute volumes-to-weight ratios. Additionally, their shorter stature may lead to exposure to higher concentrations near the ground level compared to adults.
Skin or eye contact: Even low concentrations of airborne or solution-based ammonia can swiftly cause skin or eye irritation. Elevated concentrations may result in severe injuries and burns. Contact with highly concentrated ammonia solutions, such as those used in industrial cleaners, can lead to corrosive injuries, including skin burns, permanent eye damage, or blindness. The full extent of eye injuries may not become apparent until up to a week after exposure. Direct contact with liquefied ammonia can also cause frostbite injuries.
Ingestion: Swallowing highly concentrated ammonia solutions can result in corrosive damage to the mouth, throat, and stomach. However, ingestion of ammonia typically does not lead to systemic poisoning.
While there is no specific antidote for ammonia poisoning, prompt treatment can mitigate its effects, with most individuals recovering fully. Immediate decontamination of the skin and eyes using abundant amounts of water is crucial. Treatment primarily involves supportive measures, potentially including the administration of humidified oxygen, bronchodilators, and airway management. In cases of ingestion, ammonia can be diluted with milk or water.
Laboratory tests for detecting ammonia exposure typically do not guide emergency treatment decisions. Although medical tests capable of identifying ammonia in blood or urine exist, they do not serve as definitive biomarkers of exposure due to the body's natural presence of ammonia. Following exposure to low levels, ammonia is swiftly eliminated from the body or metabolized into compounds naturally occurring at significant levels. Clinical indicators of body ammonia or nitrogen levels post-exposure to external ammonia typically show little to no deviation from baseline levels. High concentrations of exposure usually manifest immediate and evident toxicity, thus often providing sufficient grounds for diagnosis.
