| Airborne (or windborne) | Nutrients carried or distributed by air. |
| AIS | Automatic Identification System with devices on ships that allow for real-time surveillance and statistics of movement of ships. |
| Anthropogenic | Caused by human activities. |
| Atmospheric deposition | Airborne nutrients or other chemical substances originating from emissions to the air and deposited from the air on the surface (land and water surfaces). |
| BAP (or BP) | Baltic Proper |
| BAS | The entire Baltic Sea (as a sum of the Baltic Sea sub-basins). See the definition of sub-basins. |
| BNI | Baltic Nest Institute, Stockholm University, Sweden. |
| BOB (or BB) | Bothnian Bay |
| BOS (or BS) | Bothnian Sea |
| BSAP | Baltic Sea Action Plan |
| BY | Belarus |
| Catchment area | The area of land bounded by watersheds draining into a body of water (river, basin, reservoir, sea). |
| Contracting Parties | Signatories of the Helsinki Convention (Denmark, Estonia, European Commission, Finland, Germany, Latvia, Lithuania, Poland, Russia and Sweden). |
| Country-Allocated Reduction Targets (CART) | Country-wise requirements to reduce waterborne and airborne nutrient inputs (in tonnes per year) to reach the maximum allowable nutrient input levels in accordance to the Baltic Sea Action Plan. |
| CZ | Czech Republic |
| DCE | Danish for the Environment and Energy, Aarhus University, Denmark. |
| DE | Germany |
| Diffuse sources | Sources without distinct points of emission e.g. agricultural and forest land, natural background sources, scattered dwellings, atmospheric deposition (mainly in rural areas) |
| DIN and DIP | Dissolved inorganic nitrogen and dissolved inorganic phosphorus compounds. |
| Direct Sources | Point sources discharging directly to coastal or transitional waters. |
| DK | Denmark |
| DS | Danish Straits |
| EE | Estonia |
| EMEP | Cooperative Programme for Monitoring and Evaluation of the Long-range Transmission of Air Pollutants in Europe |
| Eutrophication | Condition in an aquatic ecosystem where increased nutrient concentrations stimulate excessive primary production, which leads to an imbalanced function of the ecosystem. |
| FI | Finland |
| Flow normalization | A statistical method that adjusts a data time series by removing the influence of variations imposed by river flow, e.g. to facilitate assessment of development in e.g. nitrogen or phosphorus inputs. |
| FR | France |
| GB | Great Britain |
| GUF (or GF) | Gulf of Finland |
| GUR (or GR) | Gulf of Riga |
| KAT (or KT) | Kattegat |
| HELCOM LOAD | HELCOM Expert Group on follow-up of national progress towards reaching BSAP nutrient reduction targets |
| LT | Lithuania |
| LV | Latvia |
| Maximum Allowable Input (MAI) | The maximum annual amount of a substance that a Baltic Sea sub-basin may receive and still fulfil HELCOM’s ecological objectives for a Baltic Sea unaffected by Eutrophication. |
| Monitored areas | The catchment area upstream of the river monitoring station. The chemical monitoring decides the monitored area in cases where the locations of chemical and hydrological monitoring stations do not coincide. |
| Monitoring stations | Stations where hydrographic and/or chemical parameters are monitored. |
| MSFD | EU Marine Strategy Framework Directive |
| MWWTP | Municipal wastewater treatment plant |
| NL | Netherlands |
| Non-contracting parties | Countries that are not partners to the Helsinki Convention 1992, but that have an indirect effect on the Baltic Sea by contributing with inputs of nutrients or other substances via water and/or air. |
| NOS | North Sea Shipping |
| Nutrient input ceiling (NIC) | The allowable amount of nitrogen and phosphorus input per country and sub-basin. It is calculated by subtracting the national CART from the input of nitrogen and phosphorus during the reference period of the BSAP (1997-2003). |
| OC, OCa or OCw | Other countries (sources of transboundary inputs) airborne (OCa) or waterborne OCw |
| PL | Poland |
| PLC | Pollution Load Compilation |
| Point sources | Municipalities, industries and fish farms that discharge (defined by location of the outlet) into monitored areas, unmonitored areas or directly to the sea (coastal or transitional waters). |
| QA | Quality assurance |
| Reference period | 1997-2003 |
| Reference input | The average normalized water + airborne input of nitrogen and phosphorus during 1997-2003 used to calculate CART and input ceilings. The average annual nutrient input in the reference period is used as a baseline, or point of reference, for calculating changes resulting from the measures taken to reduce pollution. |
| Retention | The amount of a substance lost/retained during transport in soil and/or water including groundwater from the source to a recipient water body. Often retention is only related to inland surface waters in these guidelines. |
| Riverine inputs | The amount of a substance carried to the maritime area by a watercourse (natural or man-made) per unit of time. |
| RU | Russia |
| Statistically significant | In statistics, a result is called “statistically significant” if it is unlikely to have occurred by chance. The degree of significance is expressed by the probability, P. P< 0.05 means that the probability for a result to occur by chance is less than 5%. |
| Sub-basins | Sub-division units of the Baltic Sea: the Kattegat (KAT), Belt Sea (BES), Western Baltic (WEB), Baltic Proper (BAP), Gulf of Riga (GUR), Gulf of Finland (GUF), Archipelago Sea (ARC) Bothnian Sea (BOS) and Bothnian Bay (BOB). The whole Baltic Sea is abbreviated BAS. |
| SE | Sweden |
| SS | Baltic Sea Shipping |
| Transboundary input | Transport of an amount of a substance (via air or water) across a country border. |
| TN and TP | Total nitrogen and total phosphorus which includes all fractions of nitrogen and phosphorus. |
| UA | Ukraine |
| Unmonitored area | Any sub-catchment(s) located downstream of the (riverine) chemical monitoring point within the catchment and further all unmonitored catchments; e.g. partly monitored rivers, unmonitored part of monitored rivers, unmonitored rivers and coastal areas including unmonitored islands.In previous versions of the guidelines, direct diffuse sources (scattered dwellings and storm waters overflows) were reported separately and some countries also reported coastal areas separately. These are now reported as part of the unmonitored area. |
| Waterborne | Substances carried or distributed by water. |
| WFD | EU Water Framework Directive |
