Ammonia (NH3) is a chemical compound composed of nitrogen and hydrogen atoms. It is widely encountered in both human activities and natural systems, playing a role in agriculture, industry, and Earth’s biological cycles.
Characteristics of Ammonia
Ammonia is a colorless gas with a distinct, pungent odor that can irritate the eyes. Its molecular structure, with a central nitrogen atom bonded to three hydrogen atoms, forms a trigonal pyramidal shape. This arrangement contributes to its polar nature and ability to form hydrogen bonds, explaining why it is easily liquefied by cooling under pressure.
The compound is highly soluble in water, dissolving readily to form ammonium hydroxide, an alkaline solution often called household ammonia. Ammonia acts as a weak base, reacting with acids to form various ammonium salts. While its vapor is lighter than air, escaping liquid ammonia can create a visible white cloud that may stay close to the ground.
Common Uses of Ammonia
Ammonia’s primary application is as a nitrogen source in agricultural fertilizers. Approximately 70% to 90% of industrially produced ammonia is converted into forms like anhydrous ammonia, urea, ammonium nitrate, and diammonium phosphate. These provide nitrogen essential for plant growth and increased crop yields.
Beyond agriculture, ammonia is a common ingredient in household cleaning products, valued for its effectiveness as a degreaser and cleaner. In industrial settings, ammonia functions as a refrigerant due to its low boiling point and heat-absorbing properties. It also serves as a chemical building block for manufacturing products including plastics, pharmaceuticals, explosives, nitric acid, and dyes, and is used in water treatment processes.
Ammonia Health and Safety
Exposure to ammonia can occur through inhalation, direct contact with skin or eyes, or accidental ingestion. Inhaling ammonia vapors can irritate the respiratory tract, leading to symptoms such as coughing, shortness of breath, and difficulty breathing. High concentrations can cause severe damage, including burns to the respiratory tract, pulmonary edema, and respiratory failure.
Skin contact with ammonia gas or solutions can result in irritation and chemical burns, while direct contact with liquefied ammonia can cause frostbite. Eye exposure can lead to severe irritation, burns, and permanent damage or blindness. If ammonia is ingested, it can cause corrosion to the esophagus and stomach, accompanied by pain, coughing, vomiting, and collapse.
Proper ventilation is necessary when handling ammonia to prevent vapor accumulation. Wearing personal protective equipment, including gloves, eye protection, and respiratory protection, is advisable.
In case of inhalation, move the affected individual to fresh air; if breathing is difficult, oxygen should be administered. For skin or eye contact, flush the affected area with plenty of water for at least 15 minutes while removing contaminated clothing, then seek immediate medical attention. If liquid ammonia causes frostbite, affected areas should not be rubbed or rewarmed with direct heat. Ingesting ammonia requires giving large quantities of water without inducing vomiting, and seeking urgent medical care.
Ammonia’s Environmental Presence
Ammonia is a natural component of the environment, playing a role in the Earth’s nitrogen cycle. It is formed through ammonification, where soil bacteria and decomposers break down organic waste and dead organisms, returning nitrogen to the soil. Nitrogen fixation involves bacteria converting atmospheric nitrogen gas into usable forms like ammonia, which plants absorb. Ammonia is also found naturally in animal waste.
Human activities contribute to ammonia’s environmental presence. Agricultural practices, such as the use of synthetic fertilizers and animal waste management, release ammonia into the atmosphere and water bodies. Industrial processes and the combustion of fossil fuels also contribute to these emissions.
Once released, ammonia can have several environmental impacts. In the atmosphere, it can combine with other pollutants to form fine particulate matter, contributing to air pollution. Ammonia can also react with atmospheric water to form acid rain, acidifying soils and water systems. Excess nitrogen from agricultural runoff, including ammonia, can enter freshwater and coastal ecosystems, leading to eutrophication. This process involves an overgrowth of algae, which can deplete oxygen levels in the water, harming aquatic life and reducing biodiversity.