Ammonia is a colorless gas with a pungent odor that is extremely soluble in water to form ammonium hydroxide. It is widely used industrially as a catalyst and reagent. Ammonia's main uses are as a refrigerant and in manufacturing fertilizers. Acute exposure to ammonia can cause irritation of the eyes and respiratory tract above 30-50 ppm. Concentrations between 500-1000 ppm can be life-threatening, resulting in chemical burns, laryngeal edema, pulmonary edema, bronchopneumonia and death. Even after surviving acute exposure, long-term respiratory disabilities may develop.

1. Ammonia NH3
Dr S K Haldar

2. Characteristics:-
• Anhydrous Ammonia is a colorless gas with a
distinct pungent odour.
• It is extremely soluble in the water forming a
caustic alkaline solution of ammonium
hydroxide (NH4OH).
• It is one of the most widely used industrial
gases as a catalyst & reagent.

3. Main Use:-
1) As a Refrigerant
2) To Manufacture Fertilizers
• Although the gas is lighter than air it can
behave paradoxically in an accidental release
from storage in liquid form under pressure by
undergoing rapid cooling to form a dense
cloud that hugs the ground.

4. Toxic Effects:-
Acute:-
1) Smell felt at 30-50 ppm and there is irritation of Eyes &
Mucous Membrane of Respiratory Tract.
2) Up to 500 ppm:- Cough, Hoarseness of Voice, Tightness of
Throat, Eye Irritation & Conjunctivitis like symptoms.
3) 500-1,000 ppm:- It is life threatening & causes
a) Chemical Burns of Nose, Mouth, Throat & Cornea
b) Laryngeal Edema
c) Pulmonary Edema
d) Bronchopneumonia
e) Hoarseness & Dyspnoea
f) Death due to b, c & d.

5. Toxic Effects:-
Laryngeal Spasm:- This is peculiar in Ammonia. Laryngeal Spasm &
Spasm of Glottis are frequent. This can produce Asphyxia & Death, but
spasm will relief if the person becomes Unconscious.
4) Effect on Eyes:- Ophthalmic complications like - a) Corneal Opacity,
b) Cataract Formation, c) Glaucoma.
5) Effect on the Skin:- A jet of the Anhydrous Ammonia on the moist Skin
can cause second degree burns.
6) Gastritis:- It continues several months after a gasing exposure.
7) The person who survives as acute gasing attack may develop permanent
Respiratory Disabilities like a) Progressive Airway Obstruction
b) Decreased Diffusion Capacity c) Bronchiolitis Oblitarance
d) Bronchiactasis e) Continuous Cough & Sputum.