Found 9887 publications. Showing page 331 of 396:
This study aimed to assess whether building materials,
furniture, and user equipment are sources of pollution
that would influence the need for ventilation. Between
2017-2020, measurements were taken in four regular
classrooms in a low emitting school and four modular
classrooms in a prefabricated school. Weekly passive
sampling of volatile organic compounds (VOCs) and
aldehydes were carried out in the classrooms under
the following four conditions: 1) emptied, 2) furnished,
3) with furniture and user equipment, and 4) during
normal use. For the first three conditions, the
classrooms were measured with either no ventilation
or "low" airflow rates. Total VOC (TVOC)
concentrations were up to ten times higher in the
unventilated classroom at the prefabricated school
compared to classrooms at the low emitting school
(<450 µg/m3 for conditions 1-2). Our results show the
importance of selecting low emitting building
materials and proper ventilation.
2021
Black Carbon (BC) aerosol is a major climate forcer in the Arctic. Here, we present 15 years (2001–2015) of surface observations of the aerosol absorption coefficient babs (corresponding to Equivalent BC), obtained at the Zeppelin Observatory, Ny Ålesund, Svalbard, coupled with backward transport modeling with Flexpart in order to calculate the Potential Source Contribution Function (PSCF) for BC. The observed long-term variability superimposed on a strong annual cycle is studied as a function of large-scale circulation patterns represented by monthly index values for the North Atlantic Oscillation (NAO) and the Scandinavian pattern (SCAN). We find a 35% increase of babs values at Zeppelin during the SCAN+ phase in the winter half-year compared to the SCAN+ phase but no significant difference in babs values between the NAO index phases. Both NAO and SCAN induce significant regional variability on the areas of origin of babs, mainly Siberia, Europe, and North America.
American Geophysical Union (AGU)
2021
Concerns have been raised as to whether gunshot fumes induce prolonged reduced lung capacity or even cancer due to inhalation. Gunshot fumes from three different types of ammunition calibre 5.56 mm × 45 NATO were investigated. SS109 has a soft lead (Pb) core, while NM255 and NM229 have a harder steel core. Emissions from ammunitions were characterized with respect to particle number- and mass-size, and mass distribution, heavy metal content, and different gases. Lung epithelial cells were exposed to the fumes at the air liquid interface to elucidate cytotoxicity and genotoxicity. Irrespectively of ammunition type, the largest mass fraction of generated particulate matter (PM) had a size between 1 and 3 μm. The highest number of particles generated was in the size range of 30 nm. Fumes from NM255 and NM229 induced cytotoxic effects of which the emission from NM229 induced the highest effect. Fumes from NM229 induced a dose-related increase in DNA-damage. Significant effects were only achieved at the highest exposure level, which led to approximately 40% reduced cell viability after 24 h. The effect probably relates to the mass of emitted particles where the size may be of importance, in addition to emission of Cu and Zn. A complex mixture of chemical substances and PM may increase the toxicity of the fumes and should encourage measures to reduce exposure.
Elsevier
2021
Changes in black carbon emissions over Europe due to COVID-19 lockdowns
Following the emergence of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) responsible for COVID-19 in December 2019 in Wuhan (China) and its spread to the rest of the world, the World Health Organization declared a global pandemic in March 2020. Without effective treatment in the initial pandemic phase, social distancing and mandatory quarantines were introduced as the only available preventative measure. In contrast to the detrimental societal impacts, air quality improved in all countries in which strict lockdowns were applied, due to lower pollutant emissions. Here we investigate the effects of the COVID-19 lockdowns in Europe on ambient black carbon (BC), which affects climate and damages health, using in situ observations from 17 European stations in a Bayesian inversion framework. BC emissions declined by 23 kt in Europe (20 % in Italy, 40 % in Germany, 34 % in Spain, 22 % in France) during lockdowns compared to the same period in the previous 5 years, which is partially attributed to COVID-19 measures. BC temporal variation in the countries enduring the most drastic restrictions showed the most distinct lockdown impacts. Increased particle light absorption in the beginning of the lockdown, confirmed by assimilated satellite and remote sensing data, suggests residential combustion was the dominant BC source. Accordingly, in central and Eastern Europe, which experienced lower than average temperatures, BC was elevated compared to the previous 5 years. Nevertheless, an average decrease of 11 % was seen for the whole of Europe compared to the start of the lockdown period, with the highest peaks in France (42 %), Germany (21 %), UK (13 %), Spain (11 %) and Italy (8 %). Such a decrease was not seen in the previous years, which also confirms the impact of COVID-19 on the European emissions of BC.
2021
Eastward-propagating planetary waves prior to the January 2009 sudden stratospheric warming
Eastward-propagating planetary waves (EPWs) were investigated prior to the boreal January 2009 major sudden stratospheric warming (SSW) event simulated by the National Center for Atmospheric Research's Whole Atmosphere Community Climate Model with specified dynamics. About 22 days before SSW onset, a background flow with jet maxima around the upper polar stratosphere and subtropical mesosphere developed due to the net forcing by gravity and planetary waves. The mesospheric wind structure was largely unstable and supported a wave geometry conducive to overreflection. With a zonal phase speed of ∼10 m s−1, EPWs appeared near their turning and critical layers as wavenumber-2 perturbations in the stratosphere and mesosphere. Accompanied by upward EPW activity from the lower stratosphere, EPW growth exhibited characteristics of wave instability and overreflection.
American Geophysical Union (AGU)
2021
2021
2021
2021
2021
This report presents VOC (volatile organic compound) measurements carried out during 2019 at EMEP monitoring sites. In total, 19 sites reported VOC-data from EMEP VOC sites this year. Some of the data-sets are considered preliminary and are not included in the report.
The monitoring of VOC has become more diverse with time in terms of instrumentation. Starting in the early 1990s with standardized methods based on manual sampling in steel canisters and adsorption tubes with subsequent analyses at the lab, the methods now consist of a variety of instruments and measurement principles, including automated continuous monitors and manual flask samples.
Within the EU infrastructure project ACTRIS, data quality issues related to measurements of VOC are an important topic. Many of the institutions providing VOC-data to EMEP are participating in the ACTRIS infrastructure project, either as formal partners or on a voluntary basis. Participation in ACTRIS means an extensive effort with data-checking including detailed discussions between the ACTRIS community and individual participants. There is no doubt that this extensive effort has benefited the EMEP-program substantially and has led to improved data quality in general.
Comparison between median levels in 2019 and the medians of the previous 10-years period, revealed similar geographical patterns as in the previous years. Changes in instrumentation, procedures and station network with time make it difficult though to provide a rigorous and pan-European assessment of long-term trends of the observed VOCs. In this report, we have estimated the trends in NMHC over the 2000-2019 period at five sites by three independent statistical methods. All three methods gave comparable estimates of the trends, although the Mann-Kendall method based on annual data (compared to daily data for the other two methods) found fewer significant trends.
These estimates indicate marked differences in the long-term trends for the individual species. Small or non-significant trends were found for ethane during 2000-2019. Propane also showed fairly small reductions. On the other hand, components linked to road traffic (ethene, ethyne and benzene) showed the strongest drop in mean concentrations, up to 60-80% at some stations.
NILU
2021
Monitoring of greenhouse gases and aerosols at Svalbard and Birkenes in 2020. Annual report.
The report summarizes the activities and results of the greenhouse gas monitoring at the Zeppelin Observatory, situated on Svalbard in Arctic Norway, during the period 2001-2020, and the greenhouse gas monitoring and aerosol observations from Birkenes for 2009-2020.
NILU
2021
Black Carbon Emission Reduction Due to COVID-19 Lockdown in China
During the Lunar New Year Holiday of 2020, China implemented an unprecedented lockdown to fight the COVID-19 outbreak, which strongly affected the anthropogenic emissions. We utilized elemental carbon observations (equivalent to black carbon, BC) from 42 sites and performed inverse modeling to determine the impact of the lockdown on the weekly BC emissions and quantify the effect of the stagnant conditions on BC observations in densely populated eastern and northern China. BC emissions declined 70% (eastern China) and 48% (northern China) compared to the first half of January. In northern China, under the stagnant conditions of the first week of the lockdown, the observed BC concentrations rose unexpectedly (29%) even though the BC emissions fell. The emissions declined substantially thereafter until a week after the lockdown ended. On the contrary, in eastern China, BC emissions dropped sharply in the first week and recovered synchronously with the end of the lockdown.
American Geophysical Union (AGU)
2021
Although it has been suggested that plastic may act as a vector for pollutants into the tissue of seabirds, the bioaccumulation of harmful contaminants, such as polybrominated diphenyl ethers (PBDEs), released from ingested plastics is poorly understood. Plastic ingestion by the procellariiform species northern fulmar (Fulmarus glacialis) is well documented. In this study, we measured PBDEs levels in liver tissue of northern fulmars without and with (0.13–0.43 g per individual) stomach plastics. PBDE concentrations in the plastic sampled from the same birds were also quantified. Birds were either found dead on beaches in southern Norway or incidentally caught in longline fisheries in northern Norway. PBDEs were detected in all birds but high concentrations were only found in liver samples from beached birds, peaking at 2900 ng/g lipid weight. We found that body condition was a significant factor explaining the elevated concentration levels in livers of beached birds. BDE209 was found in ingested plastic particles and liver tissue of birds with ingested plastics but was absent in the livers of birds without ingested plastics. This strongly suggests a plastic-derived transfer and accumulation of BDE209 to the tissue of fulmars, levels of which might prove useful as a general indicator of plastic ingestion in seabirds.
Elsevier
2021
2021
2021
Potential use of CAMS modelling results in air quality mapping under ETC/ATNI
ir quality European-wide annual maps based on the Regression – Interpolation – Merging Mapping (RIMM) data fusion methodology have been regularly produced, using the Air Quality e-Reporting validated (E1a) monitoring data, the EMEP modelling data and other supplementary data. In this report, we examine the use of the preliminary (E2a) monitoring data as provided up-to-date (UTD) by many European countries and as also stored in the Air Quality e-Reporting database, together with the EMEP or the Copernicus Atmospheric Monitoring Service (CAMS) modelling data in two variants (i.e. CAMS Ensemble Interim Reanalysis and CAMS Ensemble Forecast) for potential preparing of preliminary spatial maps. With respect to the availability, the CAMS Ensemble Forecast is the most useful in the potential interim mapping. Such preliminary maps could be constructed approximately one year earlier than the validated maps. Even though we have demonstrated the feasibility, the mapping performance presented in the report is influenced by the lack of the E2a data in some areas.
Next to the evaluation of potential interim maps, regular RIMM maps based on the validated E1a measurement data using three different chemical transport model outputs have been compared, i.e. using the CAMS Ensemble Forecast, the CAMS Ensemble Interim Reanalysis and the EMEP model outputs. Based on the evaluation of the results presented, it is not possible to conclude that any of the three model datasets gives definitively better results compared to the others. The results do not provide strong reasons for a potential change of the model used in the regular mapping.
In addition, the RIMM mapping results have been compared with the CAMS Ensemble Forecast and the CAMS Ensemble Interim Reanalysis outputs. The comparison shows that the data fusion RIMM method gives better results, both in the rural and urban background areas, presumably because of the higher spatial resolution, introduction of additional ancillary data in the data fusion and not fully reduced bias in some data assimilation methods used in CAMS.
ETC/ATNI
2021
Monitoring of the atmospheric ozone layer and natural ultraviolet radiation. Annual Report 2020.
This report summarizes the results from the Norwegian monitoring programme on stratospheric ozone and UV radiation measurements. The ozone layer has been measured at three locations since 1979: In Oslo/Kjeller, Tromsø/Andøya and Ny-Ålesund. The UV measurements started in 1995. The results show that there was a significant decrease in stratospheric ozone above Norway between 1979 and 1997. After that, the ozone layer stabilized at a level ~2% below pre-1980 level. 2020 was characterized by a strong, cold, and persistent Arctic stratospheric vortex, leading to extensive formation of Polar Stratospheric Clouds (PSCs, mother-of-pearl clouds) and chemical ozone destruction with very low ozone values and high UV levels in the exposed regions in the spring.
NILU
2021
In birds, maternal transfer is a major exposure route for several contaminants, including poly- and perfluoroalkyl substances (PFAS). Little is known, however, about the extent of the transfer of the different PFAS compounds to the eggs, especially for alternative fluorinated compounds. In the present study, we measured legacy and emerging PFAS, including Gen-X, ADONA, and F-53B, in the plasma of prelaying black-legged kittiwake females breeding in Svalbard and the yolk of their eggs. We aimed to (1) describe the contaminant levels and patterns in both females and eggs, and (2) investigate the maternal transfer, that is, biological variables and the relationship between the females and their eggs for each compound. Contamination of both females and eggs were dominated by linPFOS then PFUnA or PFTriA. We notably found 7:3 fluorotelomer carboxylic acid─a precursor of long-chain carboxylates─in 84% of the egg yolks, and provide the first documented finding of ADONA in wildlife. Emerging compounds were all below the detection limit in female plasma. There was a linear association between females and eggs for most of the PFAS. Analyses of maternal transfer ratios in females and eggs suggest that the transfer is increasing with PFAS carbon chain length, therefore the longest chain perfluoroalkyl carboxylic acids (PFCAs) were preferentially transferred to the eggs. The mean ∑PFAS in the second-laid eggs was 73% of that in the first-laid eggs. Additional effort on assessing the outcome of maternal transfers on avian development physiology is essential, especially for PFCAs and emerging fluorinated compounds which are under-represented in experimental studies.
black-legged kittiwake Rissa tridactyla top predator Svalbard PFAS emerging contaminants
2021
Within the framework of the AeroCom (Aerosol Comparisons between Observations and Models) initiative, the state-of-the-art modelling of aerosol optical properties is assessed from 14 global models participating in the phase III control experiment (AP3). The models are similar to CMIP6/AerChemMIP Earth System Models (ESMs) and provide a robust multi-model ensemble. Inter-model spread of aerosol species lifetimes and emissions appears to be similar to that of mass extinction coefficients (MECs), suggesting that aerosol optical depth (AOD) uncertainties are associated with a broad spectrum of parameterised aerosol processes.
Total AOD is approximately the same as in AeroCom phase I (AP1) simulations. However, we find a 50 % decrease in the optical depth (OD) of black carbon (BC), attributable to a combination of decreased emissions and lifetimes. Relative contributions from sea salt (SS) and dust (DU) have shifted from being approximately equal in AP1 to SS contributing about 2∕3 of the natural AOD in AP3. This shift is linked with a decrease in DU mass burden, a lower DU MEC, and a slight decrease in DU lifetime, suggesting coarser DU particle sizes in AP3 compared to AP1.
Relative to observations, the AP3 ensemble median and most of the participating models underestimate all aerosol optical properties investigated, that is, total AOD as well as fine and coarse AOD (AODf, AODc), Ångström exponent (AE), dry surface scattering (SCdry), and absorption (ACdry) coefficients. Compared to AERONET, the models underestimate total AOD by ca. 21 % ± 20 % (as inferred from the ensemble median and interquartile range). Against satellite data, the ensemble AOD biases range from −37 % (MODIS-Terra) to −16 % (MERGED-FMI, a multi-satellite AOD product), which we explain by differences between individual satellites and AERONET measurements themselves. Correlation coefficients (R) between model and observation AOD records are generally high (R>0.75), suggesting that the models are capable of capturing spatio-temporal variations in AOD. We find a much larger underestimate in coarse AODc (∼ −45 % ± 25 %) than in fine AODf (∼ −15 % ± 25 %) with slightly increased inter-model spread compared to total AOD. These results indicate problems in the modelling of DU and SS. The AODc bias is likely due to missing DU over continental land masses (particularly over the United States, SE Asia, and S. America), while marine AERONET sites and the AATSR SU satellite data suggest more moderate oceanic biases in AODc.
Column AEs are underestimated by about 10 % ± 16 %. For situations in which measurements show AE > 2, models underestimate AERONET AE by ca. 35 %. In contrast, all models (but one) exhibit large overestimates in AE when coarse aerosol dominates (bias ca. +140 % if observed AE < 0.5). Simulated AE does not span the observed AE variability. These results indicate that models overestimate particle size (or underestimate the fine-mode fraction) for fine-dominated aerosol and underestimate size (or overestimate the fine-mode fraction) for coarse-dominated aerosol. This must have implications for lifetime, water uptake, scattering enhancement, and the aerosol radiative effect, which we can not quantify at this moment.
Comparison against Global Atmosphere Watch (GAW) in situ data results in mean bias and inter-model variations of −35 % ± 25 % and −20 % ± 18 % for SCdry and ACdry, respectively. The larger underestimate of SCdry than ACdry suggests the models will simulate an aerosol single scattering albedo that is too low. The larger underestimate of SCdry than ambient air AOD is consistent with recent findings that models overestimate scattering enhancement due to hygroscopic growth. The broadly consistent negative bias in AOD and surface scattering suggests an underestimate of aerosol radiative effects in current global aerosol models.
Considerable ...
2021
Extreme precipitation events in Norway in all seasons are often linked to atmospheric rivers (AR). We show that during the period 1979–2018 78.5% of the daily extreme precipitation events in Southwestern Norway are linked to ARs, this percentage decreasing to 59% in the more northern coastal regions and ~40% in the inland regions. The association of extreme precipitation with AR occurs most often in fall for the coastal areas and in summer inland. All Norwegian regions experience stronger winds and 1–2°C increase of the temperature at 850 hPa during AR events compared to the climatology, the extreme precipitation largely contributing to the wet climatology (only considering rainy days) in Norway but also in Denmark and Sweden when the rest of Europe is dry. A cyclone is found nearby the AR landfall point in 70% of the cases. When the cyclone is located over the British Isles, as it is typically the case when ARs reach Southeastern Norway, it is associated with cyclonic Rossby wave breaking whereas when the ARs reach more northern regions, anticyclonic wave breaking occurs over Northern Europe. Cyclone-centered composites show that the mean sea level pressure is not significantly different between the eight Norwegian regions, that baroclinic interaction can still take place although the cyclone is close to its decay phase and that the maximum precipitation occurs ahead of the AR. Lagrangian air parcel tracking shows that moisture uptake mainly occurs over the North Atlantic for the coastal regions with an additional source over Europe for the more eastern and inland regions.
Elsevier
2021
2021