Ion chromatography is used to detect ammonium ions in ammonia gas samples absorbed by hydrochloric acid. By measuring the content of ammonium ions, the amount of absorbed ammonia can be accurately calculated based on the stoichiometric relationship of chemical reactions, thereby determining the content of ammonia in the sample. In atmospheric environmental monitoring, ammonia is a common pollutant that may come from industrial emissions, agricultural activities, etc. Measuring ammonium ions in hydrochloric acid absorbed ammonia samples can evaluate the degree of ammonia pollution in the atmosphere, providing data support for environmental quality assessment and pollution control.