Monitoring of nitrogen concentrations by the Contracting Parties of HELCOM is described on a general level in the HELCOM Monitoring Manual in the sub-programme Nutrients.
Monitoring guidelines specifying the sampling strategies for nitrate, nitrite and ammonium are adopted and published.
The monitoring activities relevant to the indicator, as currently carried out by HELCOM Contracting Parties, are described in the HELCOM Monitoring Manual sub-programme Nutrients monitoring concepts table.
Regional monitoring of dissolved inorganic nitrogen is considered sufficient to support the indicator evaluation. Increased monitoring in certain areas would further improve the confidence in future assessments.