RT Report
T1 Ammonia: Environmental Health Criteria 54
A1 United Nations Environment Programme, 
A1 World Health Organization, 
A1 International Labour Organisation, 
K1 environmental health
K1 chemical
K1 ammonia
K1 aquatic ecology
K1 carcinogen
K1 micro-organism
SN 92 4 154194 6
YR 1986
FD 1986
LK https://wedocs.unep.org/handle/20.500.11822/29331
UL https://wedocs.unep.org/handle/20.500.11822/29331
NO Ammonia (NH3) is a colourless acrid-smelling gas at ambient temperature and pressure. It can be stored and transported as a liquid at a pressure of 10 atm at 25 C. Ammonia dissolves readily in water where it forms, and is in equilibrium with, ammonium ions (NH4+). The sum of ammonia and ammonium concentrations is termed "total ammonia" and, because of the slightly different relative molecular masses, may be expressed as "total ammonia -nitrogen (NH3-N)". In most waters, NH4+ predominates, but increases in pH or temperature or decreases in ionic strength may materially increase levels of non-ionized ammonia.
DS UN Environment Document Repository
RD Sep 19, 2026