Found 9746 publications. Showing page 353 of 390:
2023
I et samarbeidsprosjekt med Lørenskog kommune utførte NILU en målekampanje rundt ett av boligbyggeprosjektene på Lørenskog. Formålet med målingene var å få økt kunnskap om svevestøvnivåer i omgivelsene til anleggsplasser. Målingene ble utført ved 2 steder rundt en byggeplass på Skårerbyen.
Måleresultatene viser at PM10 nivået var høyere rundt anleggsplassen enn ved en nærliggende veinær målestasjon. Observasjonene tyder på at anleggsaktivitet var årsaken. Et viktig resultat fra målekampanjen er at målinger av svevestøv med optiske målemetoder ikke anses som egnet i områder der anleggsstøv dominerer.
NILU
2023
Aerosol Optical Properties and Type Retrieval via Machine Learning and an All-Sky Imager
This study investigates the applicability of using the sky information from an all-sky imager (ASI) to retrieve aerosol optical properties and type. Sky information from the ASI, in terms of Red-Green-Blue (RGB) channels and sun saturation area, are imported into a supervised machine learning algorithm for estimating five different aerosol optical properties related to aerosol burden (aerosol optical depth, AOD at 440, 500 and 675 nm) and size (Ångström Exponent at 440–675 nm, and Fine Mode Fraction at 500 nm). The retrieved aerosol optical properties are compared against reference measurements from the AERONET station, showing adequate agreement (R: 0.89–0.95). The AOD errors increased for higher AOD values, whereas for AE and FMF, the biases increased for coarse particles. Regarding aerosol type classification, the retrieved properties can capture 77.5% of the total aerosol type cases, with excellent results for dust identification (>95% of the cases). The results of this work promote ASI as a valuable tool for aerosol optical properties and type retrieval.
MDPI
2023
Car tire rubber constitutes one of the largest fractions of microplastics emissions to the environment. The two main emission sources are tire wear particles (TWPs) formed through abrasion during driving and runoff of crumb rubber (CR) granulate produced from end-of-life tires that is used as infill on artificial sports fields. Both tire wear particles and crumb rubber contain a complex mixture of metal and organic chemical additives, and exposure to both the particulate forms and their leachates can cause adverse effects in aquatic species. An understanding of the exposure pathways and mechanisms of toxicity are, however, scarce. While the most abundant metals and organic chemicals in car tire rubber have multiple other applications, para-phenylenediamines (PDs) are primarily used as rubber antioxidants and were recently shown to cause negative effects in aquatic organisms. The present study investigated the responses of the marine lumpfish (Cyclopterus lumpus) to crumb rubber exposure in a controlled feeding experiment. Juvenile fish were offered crumb rubber particles with their feed for 1 week, followed by 2 weeks of depuration. Crumb rubber particle ingestion occurred in >75% of exposed individuals, with a maximum of 84 particles observed in one specimen. Gastrointestinal tract retention times varied, with some organisms having no crumb rubber particles and others still containing up to 33 crumb rubber particles at the end of the experiment. Blood samples were analyzed for metals and organic chemicals, with ICP-MS analysis revealing there was no uptake of metals by the exposed fish. Interestingly, high resolution GC-MS analysis indicated that uptake of PDs into lumpfish blood was proportionate to the number of ingested CR particles. Three of the PDs found in blood were the same as those identified in the additive mixture Vulkanox3100. N-(1,3-dimethylbutyl)-N′-phenyl-p-phenylenediamine (6PPD) was the most concentrated PD in both the crumb rubber and lumpfish blood. The transformation product 6PPD-quinone was detected in the rubber material, but not in the blood. This study demonstrates that PDs are specific and bioavailable chemicals in car tire rubber that have the potential to serve as biomarkers of recent exposure to tire chemicals, where simple blood samples could be used to assess recent tire chemical exposure in vertebrates, including humans.
Frontiers Media S.A.
2023
Brominated flame retardants (BFRs) that are gradually being phased out are being replaced by emerging BFRs. Here, we report the concentration of the α- and β-isomers of 1,2-dibromo-4-(1,2-dibromoethyl)cyclohexane (TBECH; also known as DBE-DBCH) in over 300 air, water, and precipitation samples collected between 2019 and 2022 using active air and deposition sampling as well as networks of passive air and water samplers. The sampling region includes Canada's most populated cities and areas along the St. Lawrence River and Estuary, Quebec, as well as around the Salish Sea, British Columbia. TBECH was detected in over 60 % of air samples at levels comparable to those of 2,2′,4,4′-tetrabromodiphenyl ether (BDE-47). Concentrations of TBECH and BDE-47 were typically higher in urban areas, with stronger correlations with population density during warmer deployments. Uniform α- β-TBECH ratios across space, time, and environmental media indicate the highly similar atmospheric fate of the two isomers. Although TBECH air concentrations were strongly related to temperature in urban Toronto and a remote site on the east coast, the lack of such dependence at a remote site on the west coast can be explained by the small seasonal temperature range and summertime air mass transport from the Pacific Ocean. Despite there being no evidence that TBECH has been produced, or imported for use, in Canada, it is now one of the most abundant gaseous BFRs in the Canadian atmosphere. The recorded spatial and temporal variability of TBECH suggest that its emissions are not constrained to specific locations but are generally tied to the presence of humans. The most likely explanation for its environmental occurrence in Canada is the release from imported consumer products containing TBECH. Chiral analysis suggests that despite its urban origin, at least some fraction of TBECH has experienced enantioselective processing, i.e., has volatilized from reservoirs where it has undergone microbial transformations. Microbial processes in urban soils and in marine waters may have divergent enantioselectivity.
2023
2023
We conducted a theoretical analysis of the relationship between red-to-blue (RBR) color intensities and aerosol optical properties. RBR values are obtained by radiative transfer simulations of diffuse sky radiances. Changes in atmospheric aerosol concentration (parametrized by aerosol optical depth, AOD), particle’s size distribution (parametrized by Ångström exponent, AE) and aerosols’ scattering (parametrized by single scattering albedo—SSA) lead to variability in sky radiances and, thus, affect the RBR ratio. RBR is highly sensitive to AOD as high aerosol load in the atmosphere causes high RBR. AE seems to strongly affect the RBR, while SSA effect the RBR, but not to such a great extent.
2023
Målinger av SO2 i omgivelsene til Elkem Carbon og REC Solar. Januar 2022 – desember 2022.
På oppdrag fra Elkem Carbon AS har NILU utført målinger av SO2 i omgivelsene til Elkem Carbon og REC Solar i Vågsbygd (Kristiansand kommune). Elkem Carbon har i sin tillatelse fra Miljødirektoratet krav om å gjennomføre kontinuerlig måling av SO2 i omgivelsesluft. Målingene ble utført med SO2-monitor i boligområdet på Fiskåtangen (Konsul Wilds vei). I tillegg har Elkem Carbon AS valgt å måle med passive SO2-prøvetakere ved 3 steder rundt bedriftene. Rapporten dekker målinger i perioden 1. januar – 31. desember 2022. Norske grenseverdier for luftkvalitet (SO2) ble overholdt ved Konsul Wilds vei for alle midlingsperioder krevet i forurensningsforskriften (årsmiddel, vintermiddel, døgnmiddel og timemiddel). De mest belastede stedene i måleperioden var Konsul Wilds vei nordøst og Fiskåveien rett sør for bedriftene. To døgnmidler var over 125 µg/m3 (grenseverdi, 3 tillatt), 4 døgnmidler var over øvre vurderingsterskel (75 µg/m3) og 11 døgnmidler var over nedre vurderingsterskel (50 µg/m3).
NILU
2023
2023
2023
The tropospheric NO2 column from Sentinel-5P/TROPOMI (2018–2020) and Aura/OMI (2010–2020) over Poland, notably for 7 major Polish cities, was used to assess the annual variability and the COVID-19 lockdown effect. On a national scale, during lockdown (March–June 2020), strong sources of pollution were found in Katowice and Warszawa, as well as at the power plant in Bełchatów. A gradual drop in OMI NO2 values between March and June was found for all cities and the entire domain of Poland, this being a part of the annual NO2 cycle derived for every year from 2010 to 2020. In fact, the gradual drop of NO2 in the lockdown year was within the typical monthly and annual variability. In March 2020, Kraków showed the highest NO2 reduction rate. A reduction of NO2 was observed in Gdańsk, Wrocław, and Warszawa during every month of the lock-down period. Several factors, including wind speed and direction, temperature, and increased emission sources, can limit the dispersion and removal of NO2. Although meteorological conditions have a significant impact on the annual cycle of NO2 in Poland, it is important to note that anthropogenic emissions remain the primary driver of NO2 concentrations. Therefore, the study concludes that the effect of COVID-19 restrictions on NO2 pollution was negligible and clarifies the current understanding of the COVID-19 effect over Poland, with an emphasis on hotspots in the major Polish cities and their vicinity. This is consistent with our understanding that the reduction of NO2 pollution is seen in cities due to reduced traffic (domestic, municipal, and airborne).
Frontiers Media S.A.
2023
Persistent organic pollutants (POPs) are synthetic compounds that were intentionally produced in large quantities and have been distributed in the global environment, originating a threat due to their persistence, bioaccumulative potential, and toxicity. POPs reach the Antarctic continent through long-range atmospheric transport (LRAT). In these areas, low temperatures play a significant role in the environmental fate of POPs, retaining them for a long time due to cold trapping by diffusion and wet deposition, acting as a net sink for many POPs. However, in the current context of climate change, the remobilization of POPs that were trapped in water, ice, and soil for decades is happening. Therefore, continuous monitoring of POPs in polar air is necessary to assess whether there is a recent re-release of historical pollutants back to the environment. We reviewed the scientific literature on atmospheric levels of several POP families (polychlorinated biphenyls – PCBs, hexachlorobenzene – HCB, hexachlorocyclohexanes – HCHs, and dichlorodiphenyltrichloroethane – DDT) from 1980 to 2021. We estimated the atmospheric half-life using characteristic decreasing times (TD). We observed that HCB levels in the Antarctic atmosphere were higher than the other target organochlorine pesticides (OCPs), but HCB also displayed higher fluctuations and did not show a significant decrease over time. Conversely, the atmospheric levels of HCHs, some DDTs, and PCBs have decreased significantly. The estimated atmospheric half-lives for POPs decreased in the following order: 4,4' DDE (13.5 years) > 4,4' DDD (12.8 years) > 4,4' DDT (7.4 years) > 2,4' DDE (6.4 years) > 2,4' DDT (6.3 years) > α-HCH (6 years) > HCB (6 years) > γ-HCH (4.2 years). For PCB congeners, they decreased in the following order: PCB 153 (7.6 years) > PCB 138 (6.5 years) > PCB 101 (4.7 years) > PCB 180 (4.6 years) > PCB 28 (4 years) > PCB 52 (3.7 years) > PCB 118 (3.6 years). For HCH isomers and PCBs, the Stockholm Convention (SC) ban on POPs did have an impact on decreasing their levels during the last decades. Nevertheless, their ubiquity in the Antarctic atmosphere shows the problematic issues related to highly persistent synthetic chemicals.
2023
Regionally sourced bioaerosols drive high-temperature ice nucleating particles in the Arctic
Primary biological aerosol particles (PBAP) play an important role in the climate system, facilitating the formation of ice within clouds, consequently PBAP may be important in understanding the rapidly changing Arctic. Within this work, we use single-particle fluorescence spectroscopy to identify and quantify PBAP at an Arctic mountain site, with transmission electronic microscopy analysis supporting the presence of PBAP. We find that PBAP concentrations range between 10−3–10−1 L−1 and peak in summer. Evidences suggest that the terrestrial Arctic biosphere is an important regional source of PBAP, given the high correlation to air temperature, surface albedo, surface vegetation and PBAP tracers. PBAP clearly correlate with high-temperature ice nucleating particles (INP) (>-15 °C), of which a high a fraction (>90%) are proteinaceous in summer, implying biological origin. These findings will contribute to an improved understanding of sources and characteristics of Arctic PBAP and their links to INP.
Springer Nature
2023
A rise in HFC-23 emissions from eastern Asia since 2015
Trifluoromethane (CHF3, HFC-23), one of the most potent greenhouse gases among hydrofluorocarbons (HFCs), is mainly emitted to the atmosphere as a by-product in the production of the ozone-depleting legacy refrigerant and chemical feedstock chlorodifluoromethane (CHClF2, HCFC-22). A recent study on atmospheric observation-based global HFC-23 emissions (top-down estimates) showed significant discrepancies over 2014–2017 between the increase in the observation-derived emissions and the 87 % emission reduction expected from capture and destruction processes of HFC-23 at HCFC-22 production facilities implemented by national phase-out plans (bottom-up emission estimates) (Stanley et al., 2020). However, the actual regions responsible for the increased emissions were not identified. Here, we estimate the regional top-down emissions of HFC-23 for eastern Asia based on in situ measurements at Gosan, South Korea, and show that the HFC-23 emissions from eastern China have increased from 5.0±0.4 Gg yr−1 in 2008 to 9.5±1.0 Gg yr−1 in 2019. The continuous rise since 2015 was contrary to the large emissions reduction reported under the Chinese hydrochlorofluorocarbons production phase-out management plan (HPPMP). The cumulative difference between top-down and bottom-up estimates for 2015–2019 in eastern China was Gg, which accounts for 47±11 % of the global mismatch. Our analysis based on HCFC-22 production information suggests the HFC-23 emissions rise in eastern China is more likely associated with known HCFC-22 production facilities rather than the existence of unreported, unknown HCFC-22 production, and thus observed discrepancies between top-down and bottom-up emissions could be attributed to unsuccessful factory-level HFC-23 abatement and inaccurate quantification of emission reductions.
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