This dataset includes stream and rainfall hydrochemistry of the Plynlimon research catchments in Mid Wales. The data cover the period from March 2016 to March 2019. Sampling was carried out fortnightly from March 2016 to July 2017. From August 2017 to November 2018 stream samples were collected every four weeks and the rain sample every two weeks. From December 2018 onwards all samples were collected every four weeks. Data are presented for major anions and cations, pH, conductivity, alkalinity, in-situ measurements of water temperature and stream flow for the six stream locations, and air temperature and volume for the rainfall sites. Stream samples were taken using a grab technique and filtered in the field. Rain samples were collected using bulk precipitation collectors. Fieldwork was carried out by CEH members of staff trained in the fieldwork techniques required. Chemical analysis was carried out by qualified CEH chemists at laboratories at CEH Lancaster and CEH Bangor. The Plynlimon research catchments lie within the headwaters of the River Severn and the River Wye in the uplands of mid-Wales. Intensive and long-term monitoring within the catchments underpins a wealth of hydrological and hydro-chemical research. Monitoring is funded by the Centre for Ecology & Hydrology, and is ongoing since 1968. Full details about this dataset can be found at https://doi.org/10.5285/54fe47f3-778e-4e0b-8cf5-b2fda2473b7f

This dataset includes rainfall, cloud and stream hydrochemistry of the Plynlimon research catchments in Mid Wales. The data cover the period from June 2011 to March 2016. Sampling was weekly from June 2011 to December 2011 and then fortnightly from January 2012. Data for the whole period are presented for major anions and cations, pH, conductivity, alkalinity and in-situ measurements such as water temperature and stream flow. From June 2011 to March 2013 data are also presented for a range of metals. Data are presented for the whole period for six stream locations and one rainfall site. Data are also for presented for two streams, Nant Iago and Tanllwyth and one cloud site for the period from June 2011 to July 2012. Stream samples were taken using a grab technique. Rain samples were collected using bulk precipitation collectors. Cloud samples were collected using a Centre of Ecology and Hydrology (CEH) Edinburgh pattern lidded harp type passive collector. This data presented follow on from the hydrochemical data presented in the dataset Plynlimon research catchment hydrochemistry (44095e17-43b0-45d4-a781-aab4f72da025) Fieldwork was carried out by CEH members of staff trained in the fieldwork techniques required. Chemical analysis was carried out by qualified CEH chemists at laboratories at CEH Lancaster and CEH Bangor. The Plynlimon research catchments lie within the headwaters of the River Severn and the River Wye in the uplands of mid-Wales. Intensive and long-term monitoring within the catchments underpins a wealth of hydrological and hydro-chemical research. Monitoring is funded by the Centre for Ecology & Hydrology, and is ongoing since 1968. Full details about this dataset can be found at https://doi.org/10.5285/794c609b-da62-4a42-a4c1-267219865bb1

[THIS DATASET HAS BEEN WITHDRAWN]. Atmospheric Nitrogen Dioxide data from the UK Environmental Change Network (ECN) terrestrial sites. These data (weight of NO2) are collected by diffusion tubes at all of ECN's terrestrial sites using a standard protocol. They represent continuous fortnightly records from 1993 to 2012. ECN is the UK's long-term environmental monitoring programme. It is a multi-agency programme sponsored by a consortium of fourteen government departments and agencies. These organisations contribute to the programme through funding either site monitoring and/or network co-ordination activities. These organisations are: Agri-Food and Biosciences Institute, Biotechnology and Biological Sciences Research Council, Cyfoeth Naturiol Cymru - Natural Resources Wales, Defence Science & Technology Laboratory, Department for Environment, Food and Rural Affairs, Environment Agency, Forestry Commission, Llywodraeth Cymru - Welsh Government, Natural England, Natural Environment Research Council, Northern Ireland Environment Agency, Scottish Environment Protection Agency, Scottish Government and Scottish Natural Heritage. Full details about this dataset can be found at https://doi.org/10.5285/c770b7c2-8d52-454f-936c-2999338bdee7

[THIS DATASET HAS BEEN WITHDRAWN]. Carabid beetle data from the UK Environmental Change Network (ECN) terrestrial sites. The count of individual species is recorded. These data are collected by pitfall traps at all of ECN's terrestrial sites using a standard protocol. They represent continuous fortnightly records from 1992 to 2012. ECN is the UK's long-term environmental monitoring programme. It is a multi-agency programme sponsored by a consortium of fourteen government departments and agencies. These organisations contribute to the programme through funding either site monitoring and/or network co-ordination activities. These organisations are: Agri-Food and Biosciences Institute, Biotechnology and Biological Sciences Research Council, Cyfoeth Naturiol Cymru - Natural Resources Wales, Defence Science & Technology Laboratory, Department for Environment, Food and Rural Affairs, Environment Agency, Forestry Commission, Llywodraeth Cymru - Welsh Government, Natural England, Natural Environment Research Council, Northern Ireland Environment Agency, Scottish Environment Protection Agency, Scottish Government and Scottish Natural Heritage. Full details about this dataset can be found at https://doi.org/10.5285/4c9613ce-de52-41b1-9fde-7c41f9199686