Found 9849 publications. Showing page 318 of 394:
Low-cost air quality sensor systems can be deployed at high density, making them a significant candidate of complementary tools for improved air quality assessment. However, they still suffer from poor or unknown data quality. In this paper, we report on a unique dataset including the raw sensor data of quality-controlled sensor networks along with co-located reference data sets. Sensor data are collected using the AirSensEUR sensor system, including sensors to monitor NO, NO2, O3, CO, PM2.5, PM10, PM1, CO2 and meteorological parameters. In total, 85 sensor systems were deployed throughout a year in three European cities (Antwerp, Oslo and Zagreb), resulting in a dataset comprising different meteorological and ambient conditions. The main data collection included two co-location campaigns in different seasons at an Air Quality Monitoring Station (AQMS) in each city and a deployment at various locations in each city (also including locations at other AQMSs). The dataset consists of data files with sensor and reference data, and metadata files with description of locations, deployment dates and description of sensors and reference instruments.
Springer Nature
2023
2017
Sensitivity analysis of ammonia emission reductions on exceedances of PM air quality standards. ETC/ACM Technical Paper, 2013/12
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2024
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2014
1999
Separation of volcanic ash and sulfur dioxide from the Eyjafjallajökull eruption, April-May 2010. NILU F
2010
SESS report 2018. The State of Environmental Science in Svalbard – an annual report.
Svalbard Integrated Arctic Earth Observing System (SIOS)
2019
2009
2021
2011
SF6 as a greenhouse gas: An assessment of Norwegian global sources and the global warming potential. NILU OR
1993
Sheath formation time for spherical Langmuir probes
The formation time of the surrounding sheath of Langmuir probes in an ionospheric plasma has been studied to better understand the constraints this puts on the sampling frequency of a probe. A fully kinetic three-dimensional particle-in-cell model is used to simulate the temporal effects in the electron saturation region as the sheath forms. The stability of the probe current and the stability of the ion and electron density in the vicinity of the probe have been used to evaluate when the sheath was formed. Simulated results were compared with theoretical models and are in good agreement with the theoretical results. This shows that theoretical models can be used as guidance to estimate the formation time and to determine the sampling rate for a swept bias Langmuir system. Our results also show that the formation time is less affected by the plasma temperature and bias voltage as we move into the thick sheath regime, and will instead be determined by the plasma density. The presented results also show that applying a step function to the probe could be used to characterise ions species composition, or to estimate the ion density.
Cambridge University Press
2023
Per- and polyfluoroalkyl substances (PFAS) have gained significant global attention due to their extensive industrial use and harmful effects on various organisms. Among these, perfluoroalkyl acids (PFAAs) are well-studied, but their diverse precursors remain challenging to monitor. The Total Oxidizable Precursor (TOP) assay offers a powerful approach to converting these precursors into detectable PFAAs. In this study, the TOP assay was applied to samples from the East Asian-Australian Flyway, a critical migratory route for millions of shorebirds. Samples included shellfish from China's coastal mudflats, key stopover sites for these birds, and blood and liver samples from shorebirds overwintering in Australia. The results showed a substantial increase in perfluorocarboxylic acids (PFCAs) across all sample types following the TOP assay, with the most significant increases in shorebird livers (Sum PFCAs increased by 18,156 %). Intriguingly, the assay also revealed unexpected increases in perfluorosulfonic acids (PFSAs), suggesting the presence of unidentified precursors. These findings highlight the need for further research into these unknown precursors, their sources, and their ecological impacts on shorebirds, other wildlife, and potential human exposure. This study also provides crucial insights into the TOP assay’s strengths and limitations in studying PFAS precursor dynamics in biological matrices.
Elsevier
2025
SHIPMATE - Ship traffic particulate matter emissions. Final project report. NILU report
In the SHIPMATE project, we have carried out measurements of a large number of pollutants and aerosol components at the Mt. Zeppelin observatory during 2014 and 2015, with focus on the summer period (April to September). The aims were 1) identification of the particulate matter (PM) contribution from ship emissions by source apportionment and 2) isolation of data records influenced by local ship emissions in order to preserve the usefulness of the observatory for regional trends of atmospheric constituents. A total of 8 potentially ship-influenced 3-day sampling intervals were found in the analysis of the wind direction record and the harbour calls from Ny-Ålesund (2014 and 2015). The local shipping pollution contributed significantly (¿50%) to the concentration levels of certain heavy metals such as Cu, Ni, Zn and Cd during the two summers. This is supported by the enrichment factors analysis. However, the influence of local pollution from shipping on the measurements carried out at the Mt. Zeppelin observatory is rather infrequent.
2016