Abstract

Ammonia, NH₃ [7664-41-7] is one of the most widely used chemicals having multiple industrial applications. It is used in the manufacture of fertilizers, nitric acid, explosives, synthetic fibers, urea, soda ash, dyes, amines, and many ammonium salts. Workers in these industries and also in many other areas, such as petroleum refining and glass cleaning, are susceptible to chronic exposure risks from ammonia. The Permissible Exposure Level (PEL) in the ambient air at the workplace for ammonia set by the Occupational Safety and Health Administration (OSHA) is 35 ppm (20 mg/m³). It is the Short Term Exposure Limit (STEL). The Time Weighted Average (TWA) pertaining to an 8-hour working day/5-days a week is currently under review to be lowered to a concentration of 10 mg/m³ that includes ammonia, ammonium chloride fume, or ammonium sulfamate. In this chapter, the analysis of ammonia both in water and air are presented. For the water analysis, ammonia is measured as the ammonia-nitrogen or nitrogen-ammonia (NH₃-N), and its concentration is expressed as the nitrogen equivalent of ammonia in mg/L of an aqueous sample. In air analysis, it is measured as ammonia or as the ammonium ion (NH₄+), depending on the method of analysis, and the concentration is expressed as mg NH₃/m³ of air or as part per million (ppm) equivalents.