Nitrate, ammonium (and chlorides) collected in an aerosol filter will not generally reflect the true air concentrations due to physical processes and chemical reactions on the filter, mainly with sulphuric acid. By adding the amount of ions in the aerosol filter to the amounts on alkaline and acid impregnated filters behind the aerosol filter, the sum of the concentrations of nitric acid and aerosol nitrate, ammonia and aerosol ammonium, and hydrochloric acid and aerosol chlorides can be determined. Separate determination of the gaseous and aerosol components can be achieved by use of denuders.
Extraction from aerosol filters is described in Section 3.6.
The analytical method is described in Section 4.1.
The analytical method is described in Section 4.3.1.
The analytical method is described in Section 4.3.2.
The analytical method is described in Section 4.1.
The analytical method is described in Section 4.4.1.
The analytical method is described in Section 4.4.2.