Fant 775 publikasjoner. Viser side 19 av 33:
Atmospheric corrosion due to amine emissions from carbon capture plants
The atmospheric corrosion due to pure amines emitted from carbon capture plants was investigated. Amine exposure was found to initially inhibit the corrosion of steel, by its film formation and alkalinity, but reduce corrosion product layers and lead to freezing point depression, which could in turn increase the corrosion. Very high amine doses were observed to dissolve the metal without the establishing of a corrosion layer. These effects seem much more pronounced on copper than on steel. Climate and air quality variations affect the steel corrosion much more than the expected maximum amine deposition from carbon capture plant emissions.
Elsevier
2021
2021
2021
2020
We present 18 years (2001–2018) of aerosol measurements, including organic and elemental carbon (OC andEC), organic tracers (levoglucosan, arabitol, mannitol, trehalose, glucose, and 2-methyltetrols), trace elements, andions, at the Birkenes Observatory (southern Norway) – a site representative of the northern European region. The OC/EC (2001–2018) and the levoglucosan (2008–2018) time series are the longest in Europe, with OC/EC available for the PM10, PM2.5 (fine), and PM10–2.5 (coarse) size fractions, providing the opportunity for a nearly 2-decade-long assessment. Using positive matrix factorization (PMF), we identify seven carbonaceous aerosol sources at Birkenes: mineral-dust-dominated aerosol (MIN), traffic/industry-like aerosol (TRA/IND), short-range-transported biogenic secondary organic aerosol (BSOASRT), primary biological aerosol particles (PBAP), biomass burning aerosol (BB), ammonium-nitrate-dominated aerosol (NH4NO3), and (one low carbon fraction) sea salt aerosol (SS).
We observed significant (p < 0.05), large decreases in EC in PM10 (−3.9 % yr−1) and PM2.5 (−4.2 % yr−1) anda smaller decline in levoglucosan (−2.8 % yr−1), suggesting that OC/EC from traffic and industry is decreasing, whereas the abatement of OC/EC from biomass burning has beenslightly less successful. EC abatement with respect to anthropogenic sources is further supported by decreasing EC fractions in PM2.5 (−3.9 % yr−1) and PM10(−4.5 % yr−1).
PMF apportioned 72 % of EC to fossil fuel sources; this was further supported by PMF applied to absorption photometer data, which yielded a two-factor solution with alow aerosol Ångstrøm exponent (AAE=0.93) fraction, as-sumed to be equivalent black carbon from fossil fuel combustion (eBCFF), contributing 78 % to eBC mass. The higher AAE fraction (AAE=2.04) is likely eBC from BB (eBCBB). Source–receptor model calculations (FLEXPART) showed that continental Europe and western Russia were the main source regions of both elevated eBCBB and eBCFF.
Dominating biogenic sources explain why there was no downward trend for OC. A relative increase in the OC fraction in PM2.5(+3.2 % yr−1) and PM10(+2.4 % yr−1) underscores the importance of biogenic sources at Birkene (BSOA and PBAP), which were higher in the vegetative season and dominated both fine (53 %) and coarse (78 %) OC. Furthermore, 77 %–91 % of OC in PM2.5, PM10–2.5, and PM10 was attributed to biogenic sources in summer vs. 22 %–37 % in winter. The coarse fraction had the highest share of biogenic sources regardless of season and was dominated by PBAP, except in winter. Our results show a shift in the aerosol composition at Birkenes and, thus, also in the relative source contributions. The need for diverse offline and online carbonaceous aerosol speciation to understand carbonaceous aerosol sources, including their seasonal, annual, and long-term variability, has been demonstrated.
2021
Hydrolysis of FTOH precursors, a simple method to account for some of the unknown PFAS
There is a growing concern over a suspected presense of unknown perfluoroaliphatic substances (PFAS) in consumer goods and in the environment. Such unknown substances, possibly with high molecular weight, might be precursors of hazardous or controlled known PFAS. Recent studies confirmed that total organic fluorine (TOF) content often can not be explained by the measured target PFAS. One of the suspected classes of such unknowns are polymers with fluorotelomer alcohol (FTOH) residues in a side chain. In this report we suggest hydrolysis of precursors, as a complementary method to account for the unknown PFAS. It was shown here that hydrolysis allows to preserve structural information on the perlfuorinated parts of the precursors, which can be an advantage for the purpose of accurate risk assessment or source identification. A convenient procedure for hydrolysis with 4% sodium hydroxide inwater-methanol mixture (1:9) at 60 C for 16 h was shown to convert model substances - FTOH acrylate, methacrylate and isobutyrate esters as well as FTOH phenylcarbamate to free FTOHs. Analysis of extracts of textile samples with preliminary hydrolysis and without it showed up to 1300-fold higher level of “hidden” FTOHs.
Pergamon Press
2021
Urban herring gulls (Larus argentatus) are exposed to contaminants from aquatic, terrestrial and anthropogenic sources. We aim to assess if differences in urbanisation affect ecological niche and contaminant concentrations in female herring gulls. Furthermore, we investigated maternal transfer from mothers to eggs for all the target compounds, including chlorinated paraffins (CPs) and cyclic volatile methyl siloxane (cVMSs), which to our knowledge have not been assessed in herring gulls previously. We compare concentrations of legacy and emerging contaminants and metals in blood and eggs between two herring gull colonies located 51 km apart, in the urban influenced Norwegian Oslofjord. While both colonies are within an urbanised area, the inner fjord is more so, as it is surrounded by Oslo, the capital and largest city in Norway Stable isotopes of carbon and nitrogen indicated a more marine ecological niche in the outer than the inner fjord colony, although with overlap. Persistent organic pollutant (POP) concentrations were similar in the inner and outer fjord colonies, while the short-chained chlorinated paraffins (SCCP), which are recently added to the Stockholm convention and contaminants of emerging concern (CECs) varied, with higher concentrations of SCCP and the cVMS decamethylcyclopentasiloxane (D5) in females and eggs of the inner fjord colony. Per- and polyfluorinated substances (PFAS) concentrations were higher in the outer fjord colony, likely linked to releases from a point-source (airport and waste management facility with open access to food waste). In blood, chlorinated paraffins contributed most the total lipophilic contaminants (inner: 78%, outer: 56%), while polychlorinated biphenyls (PCBs) were the most abundant lipophilic contaminants in eggs (inner: 62%, outer: 46%). Dechloranes and brominated flame retardants (BFRs) were detected in few samples. Maternal transfer, assessed by egg to blood ratios, of cVMSs were similar to the POPs with mean log ratio 0.39 (D5), while it was lower for SCCPs, with log ratios-0.77. Our results indicate comparable POP exposure of the herring gulls in the inner and outer Oslofjord, likely due to overlap in ecological niches between the colonies and wide distribution of POPs. The differences between the colonies in concentrations of PFAS, cVMS and CPs shows that point source exposures and urban influence may be more important than ecological niche for these compounds.
Elsevier
2021
American Geophysical Union (AGU)
2021
2021
The Arctic middle atmosphere was affected by major sudden stratospheric warmings (SSW) in February 2018 and January 2019, respectively. In this article, we report for the first time the impact of these two events on the middle atmospheric nitric oxide (NO) abundance. The study is based on measurements obtained during two dedicated observation campaigns, using the Sub-Millimetre Radiometer (SMR) aboard the Odin satellite, measuring NO globally since 2003. The SSW of February 2018 was similar to other, more dynamically quiet, Arctic winters in term of NO downward transport from the upper mesosphere–lower thermosphere to lower altitudes (referred to as energetic particle precipitation indirect effect EPP-IE). On the contrary, the event of January 2019 led to one of the strongest EPP-IE cases observed within the Odin operational period. Important positive NO anomalies were indeed observed in the lower mesosphere–upper stratosphere during the three months following the SSW onset, corresponding to NO volume mixing ratios more than 50 times higher than the climatological values. These different consequences on the middle atmospheric composition are explained by very different dynamical characteristics of these two SSW events.
Elsevier
2021
2021
2021
2021
2021
The long-term time trends of atmospheric pollutants at eight Arctic monitoring stations are reported. The work was conducted under the Arctic Monitoring and Assessment Programme (AMAP) of the Arctic Council. The monitoring stations were: Alert, Canada; Zeppelin, Svalbard; Stórhöfði, Iceland; Pallas, Finland; Andøya, Norway; Villum Research Station, Greenland; Tiksi and Amderma, Russia. Persistent organic pollutants (POPs) such as α- and γ-hexachlorocyclohexane (HCH), polychlorinated biphenyls (PCBs), α-endosulfan, chlordane, dichlorodiphenyltrichloroethane (DDT) and polybrominated diphenyl ethers (PBDEs) showed declining trends in air at all stations. However, hexachlorobenzene (HCB), one of the initial twelve POPs listed in the Stockholm Convention in 2004, showed either increasing or non-changing trends at the stations. Many POPs demonstrated seasonality but the patterns were not consistent among the chemicals and stations. Some chemicals showed winter minimum and summer maximum concentrations at one station but not another, and vice versa. The ratios of chlordane isomers and DDT species showed that they were aged residues. Time trends of perfluorooctanoic acid (PFOA) and perfluorooctane sulfonic acid (PFOS) were showing decreasing concentrations at Alert, Zeppelin and Andøya. The Chemicals of Emerging Arctic Concern (CEAC) were either showing stable or increasing trends. These include methoxychlor, perfluorohexane sulfonic acid (PFHxS), 6:2 fluorotelomer alcohol, and C9-C11 perfluorocarboxylic acids (PFCAs). We have demonstrated the importance of monitoring CEAC before they are being regulated because model calculations to predict their transport mechanisms and fate cannot be made due to the lack of emission inventories. We should maintain long-term monitoring programmes with consistent data quality in order to evaluate the effectiveness of chemical control efforts taken by countries worldwide.
Elsevier
2021
American Meteorological Society
2021
Implementing Citizen Science in Primary Schools: Engaging Young Children in Monitoring Air Pollution
Frontiers Media S.A.
2021
Instead of a flag valid/non-valid usually proposed in the quality control (QC) processes of air quality (AQ), we proposed a method that predicts the p-value of each observation as a value between 0 and 1. We based our error predictions on three approaches: the one proposed by the Working Group on Guidance for the Demonstration of Equivalence (European Commission (2010)), the one proposed by Wager (Journal of Machine Learning Research, 15, 1625–1651 (2014)) and the one proposed by Lu (Journal of Machine Learning Research, 22, 1–41 (2021)). Total Error framework enables to differentiate the different errors: input, output, structural modeling and remnant. We thus theoretically described a one-site AQ prediction based on a multi-site network using Random Forest for regression in a Total Error framework. We demonstrated the methodology with a dataset of hourly nitrogen dioxide measured by a network of monitoring stations located in Oslo, Norway and implemented the error predictions for the three approaches. The results indicate that a simple one-site AQ prediction based on a multi-site network using Random Forest for regression provides moderate metrics for fixed stations. According to the diagnostic based on predictive qq-plot and among the three approaches used in this study, the approach proposed by Lu provides better error predictions. Furthermore, ensuring a high precision of the error prediction requires efforts on getting accurate input, output and prediction model and limiting our lack of knowledge about the “true” AQ phenomena. We put effort in quantifying each type of error involved in the error prediction to assess the error prediction model and further improving it in terms of performance and precision.
MDPI
2021
2021
2021
Ftalater er organiske stoffer som hovedsakelig brukes til å gjøre plast mykere, særlig i PVC. Produksjonen av disse forbindelsene er ikke regulert på globalt nivå. Vi undersøkte nivåer av 12 ftalater i fett/spekk fra blåhval, finnhval, grønlandshval og isbjørn fra norsk Arktis. I tillegg målte vi nivåer av nedbrytningsprodukter av ftalater i plasma fra isbjørn. Bis(2-etylhexyl) ftalat (DEHP) var den eneste ftalat-forbindelsen som ble kvantifisert i prøvene. DEHP var til stede i de fleste hvalprøvene og nivåene i blå- og finnhvalspekk var lik nivåer av kjente miljøgifter som PCBer og organiske plantevernmidler. Nedbrytningsprodukter av ftalater ble funnet i lave konsentrasjoner i noen få isbjørnprøver. I tillegg undersøkte vi ftalaters potensial til å forstyrre finnhvalenes kjernereseptorer. Kjernereseptorer er proteiner som regulerer gener. De studerte reseptorene er viktige for å regulere blant annet metabolisme, stressresponser og energibalanse. Vi fant at DEHP både kan øke og hemme aktiviteten til skjoldbruskkjertelhormonreseptor, men da i høyere konsentrasjoner enn det som ble målt i spekk-/fettprøvene. Siden de studerte finnhvalreseptorene er helt eller nesten like de som finnes hos mange andre arter inkludert blåhval, vågehval, spekkhoggere, hvithval, isbjørn og mennesker, er resultatene også relevante for disse artene. Dette studiet bidrar til å øke kunnskapen om plastrelaterte stoffer og deres potensial til å forstyrre hormonsystemet hos marine pattedyr fra norsk Arktis.
Elsevier
2021
2021
2021
Pergamon Press
2021