Pressure layer combines all human activities that cause changes to hydrological conditions. The human activities were presented as point data which were given spatial extents (given below). The pressure value was given as the proportion of the grid cell under the pressure. The following human activities were combined into the changes to hydrological conditions layer; - Hydropower dams (a 1km2 grid cell in the river estuary was selected) - Water course modification (1 km) - Wind turbines (operational, 0.3 km, linear decline) - Oil platforms (0.5 km, linear decline) The human activity datasets were first processed separately covering the whole Baltic Sea and then summed together and overlapping areas were dissolved to remove double counting. Attenuation gradients are assigned to each layer as described above. Area effected decreases when distance from avtivity increases. Layer was normalized.

This pressure dataset is derived from three human activities datasets - Urban land use (on land) - Recreational boating and sports (updated layer for 2018 version, please see separate http://metadata.helcom.fi/geonetwork/srv/eng/catalog.search#/metadata/8c30e828-1340-4162-b7f9-254586ae32b6) - Bathing sites These data are described in more detail in separate fact sheets. Urban land use data was first converted to 1 km grid cells and expanded with 1 km. Thus, coastal urban areas extended also to the sea. These areas were given value 1 and other sea areas, value 0. Bathing sites (points) were converted to 1km grid and given value 1, rest of the sea areas were given value 0. Normalized recreational boating data was converted to 1 km grid cells. These three layers were summed to produce the layer (values from 0 to 3), after that the layer was normalized. Hunting and recreational fishing data were excluded from human disturbance layer, as they are mostly reported per country and would have resulted in overestimation of the actual pressure.

Concentration of nitrogen pressure layer is interpolated from annual seasonal average of total nitrogen concentrations from surface waters (0-10 m) extracted from ICES’s oceanographic database, database of Swedish Meteorological and Hydrological Institute, EEA’s Eionet database and Data from Gulf of Finland year 2014. The points were interpolated to cover the entire Baltic Sea with Spline with barriers interpolation method. Values were log-transformed and normalised (more detailed description below).

Input of hazardous substances pressure layer is interpolated from CHASE Assessment tool concentration component. The contamination ratio values were calculated with CHASE Assessment tool for hazardous substances monitored in water, sediment and biota. Classified mean contamination ratio was used in the interpolation. Classification is based on the http://stateofthebalticsea.helcom.fi/about-helcom-and-the-assessment/downloads-and-data/. The points were interpolated to cover the entire Baltic Sea with Spline with barriers interpolation method. Please see "lineage" section below for further details on attributes, data source, data processing, etc.

This dataset reflects spatial distribution of nutrients load and load of selected hazardous substances on the Baltic Sea from land based sources. The data, obtained through national monitoring programmes in 2014, were reported by Contracting Parties to HELCOM in the frame of HELCOM PLC-6 project and collected in the HELCOM Pollution Load Compilation (PLC-water) database (http://apps.nest.su.se/helcom_plus/). The reporting was organized in accordance with the HELCOM Guidelines for the annual and periodical compilation and reporting of waterborne pollution inputs to the Baltic Sea (PLC-Water, http://www.helcom.fi/Lists/Publications/PLC-Water%20Guidelines.pdf). The dataset has been produced based on guidance by HELCOM PRESSURE and REDCORE Drafting Group. The dataset contains following attributes: Station code: unique code of the monitoring station Station name: station name Latitude: latitude Longitude: longitude

This dataset reflects spatial distribution of nutrients load and load of selected hazardous substances on the Baltic Sea from land based sources. The data, obtained through national monitoring programmes in 2014, were reported by Contracting Parties to HELCOM in the frame of HELCOM PLC-6 project and collected in the HELCOM Pollution Load Compilation (PLC-water) database (http://apps.nest.su.se/helcom_plus/). The reporting was organized in accordance with the HELCOM Guidelines for the annual and periodical compilation and reporting of waterborne pollution inputs to the Baltic Sea (PLC-Water, http://www.helcom.fi/Lists/Publications/PLC-Water%20Guidelines.pdf). The dataset has been produced based on guidance by HELCOM PRESSURE and REDCORE Drafting Group. The dataset contains following attributes: Unique code: unique code of the source Name: subcatchment name Country: country in the BS catchment area PLC Basin: Baltic Sea PLC Basin Year: data year Conc_TN: Nitrogen concentrations Conc_TP: Phosphorus concentratios Latitude: latitude Longitude: longitude Station code: unique code of the monitoring station

This dataset reflects spatial distribution of nutrients load and load of selected hazardous substances on the Baltic Sea from land based sources. The data, obtained through national monitoring programmes in 2014, were reported by Contracting Parties to HELCOM in the frame of HELCOM PLC-6 project and collected in the HELCOM Pollution Load Compilation (PLC-water) database (http://apps.nest.su.se/helcom_plus/). The reporting was organized in accordance with the HELCOM Guidelines for the annual and periodical compilation and reporting of waterborne pollution inputs to the Baltic Sea (PLC-Water, http://www.helcom.fi/Lists/Publications/PLC-Water%20Guidelines.pdf). The dataset has been produced based on guidance by HELCOM PRESSURE and REDCORE Drafting Group. The dataset contains following attributes: Unique code: unique code of the source Name: source name Country: country in the BS catchment area PLC sub-basin: Baltic Sea PLC sub-basin Total annual Cd discharge: total annual discharge of Cadmium Total annual Hg discharge: total annual discharge of Mercury Total annual Pb discharge: total annual discharge of Lead

This dataset reflects spatial distribution of nutrients load and load of selected hazardous substances on the Baltic Sea from land based sources. The data, obtained through national monitoring programmes in 2014, were reported by Contracting Parties to HELCOM in the frame of HELCOM PLC-6 project and collected in the HELCOM Pollution Load Compilation (PLC-water) database (http://apps.nest.su.se/helcom_plus/). The reporting was organized in accordance with the HELCOM Guidelines for the annual and periodical compilation and reporting of waterborne pollution inputs to the Baltic Sea (PLC-Water, http://www.helcom.fi/Lists/Publications/PLC-Water%20Guidelines.pdf). The dataset has been produced based on guidance by HELCOM PRESSURE and REDCORE Drafting Group. The dataset contains following attributes: Station code: unique code of the monitoring station Station name: station name Latitude: latitude Longitude: longitude

This dataset reflects spatial distribution of nutrients load and load of selected hazardous substances on the Baltic Sea from land based sources. The data, obtained through national monitoring programmes in 2014, were reported by Contracting Parties to HELCOM in the frame of HELCOM PLC-6 project and collected in the HELCOM Pollution Load Compilation (PLC-water) database (http://apps.nest.su.se/helcom_plus/). The reporting was organized in accordance with the HELCOM Guidelines for the annual and periodical compilation and reporting of waterborne pollution inputs to the Baltic Sea (PLC-Water, http://www.helcom.fi/Lists/Publications/PLC-Water%20Guidelines.pdf). The dataset has been produced based on guidance by HELCOM PRESSURE and REDCORE Drafting Group. The dataset contains following attributes: Unique code: unique code of the aquaculture Producer: name of the producer Country: country in the BS catchment area Sub-basin: Baltic Sea PLC sub-basin Total annual N load: Total annual N load Total annual P load: Total annual P load

This dataset reflects spatial distribution of nutrients load and load of selected hazardous substances on the Baltic Sea from land based sources. The data, obtained through national monitoring programmes in 2014, were reported by Contracting Parties to HELCOM in the frame of HELCOM PLC-6 project and collected in the HELCOM Pollution Load Compilation (PLC-water) database (http://apps.nest.su.se/helcom_plus/). The reporting was organized in accordance with the HELCOM Guidelines for the annual and periodical compilation and reporting of waterborne pollution inputs to the Baltic Sea (PLC-Water, http://www.helcom.fi/Lists/Publications/PLC-Water%20Guidelines.pdf). The dataset has been produced based on guidance by HELCOM PRESSURE and REDCORE Drafting Group. The dataset contains following attributes: Station code: unique code of the monitoring station Name: subcatchment name Latitude: latitude Longitude: longitude Source code: unique code of the source Country: country in the BS catchment area PLC Basin: Baltic Sea PLC Basin Year: data year Flow: flow value TN: Nitrogen load TP: Phosphorus load NormTN: normalized nitrogen load NormTP: normalized phosphorus load