This standard is formulated for the purposes of enforcing the Environment Protection Law of the People’s Republic of China and the Law of the People’s Republic of China on Prevention and Control of Air Pollution, protecting the environment, safeguarding the public health, and setting standards for the determination of the water soluble cations (Li+、Na+、NH4+、K+、Ca2+、Mg2+) in ambient air. This standard specifies the ion chromatography used to determine six water soluble cations (Li+、Na+、NH4+、K+、Ca2+、Mg2+) from atmospheric particles. This standard is the original version.