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Using the Super Dual Auroral Radar Network observations (clustered around 60°N) and NCAR CESM2.0 extended Whole Atmosphere Community Climate Model nudged with reanalyzes, we examine the climatology of semidiurnal tides in meridional wind associated with the migrating component (SW2) and non‐migrating components of wavenumbers 1 (SW1) and 3 (SW3). We then illustrate their composite response to major sudden stratospheric warmings (SSWs). Peaking in late summer and winter, the climatological SW2 amplitude exceeds SW1 and SW3 except around late Fall and Spring. The winter climatological peak is absent in the model perhaps due to the zonal wind bias at the observed altitudes. The observed SW2 amplitude declines after SSW onset before enhancing ∼10 days later, along with SW1 and SW3. Within the observed region, the simulated SW2 only amplifies after SSW onset, with minimal SW1 and SW3 responses. The model reveals a stronger SW2 response above the observed location, with diminished amplitude before and enhancement after SSW globally. This enhancement appears related to increased equatorial ozone heating and background wind symmetry. The strongest SW1 and SW3 growth occurs in the Southern Hemisphere before SSW. SW2 and quasi‐stationary planetary wave activities are temporally collocated during SSW suggesting that their interactions excite SW1 and SW3. After SSW, the model also reveals (1) semidiurnal‐tide‐like perturbations generated possibly by the interactions between SW2 and westward‐traveling disturbances and (2) the enhancement of migrating semidiurnal lunar tide in the Northern Hemisphere that exceeds non‐migrating tidal and semidiurnal‐tide‐like responses. The simulated eastward‐propagating semidiurnal tides are briefly examined.
2021
This study investigated concentrations of phthalates (diesters of phthalic acids) in blubber/adipose tissue of blue whales (Balaenoptera musculus), fin whales (Balaenoptera physalus), bowhead whales (Balaena mysticetus) and polar bears (Ursus maritimus) sampled in the Svalbard Archipelago (extending westward in the case of bowhead whales). Additionally, total concentrations (free and conjugated forms) of eight phthalate monoester metabolites were analysed in plasma of polar bears. Bis(2-ethylhexyl) phthalate (DEHP) was the only phthalate quantified among the 12 phthalates investigated. This compound was present in 6/7 fin whale samples, 4/7 blue whale samples, 2/5 bowhead whale samples and 1/12 polar bear samples. DEHP concentrations ranged from <20–398 ng/g wet weight. Phthalate metabolites, mono-n-butyl phthalate and monoisobutyl phthalate, were found in low concentrations (<1.2 ng/mL) in some of the polar bear samples. In vitro reporter gene assays were used to assess transcriptional activity of fin whale peroxisome proliferator-activated receptor gamma (PPARG), glucocorticoid receptor (GR) and the thyroid hormone receptor beta (THRB) by DEHP and diisononyl phthalate (DiNP). Due to the high degree of similarity of the ligand binding domain in the THRB and PPARG among whales, polar bears and humans, the transactivation results also apply for these species. DEHP showed both agonistic and antagonistic effects towards whale THRB at considerably higher concentrations than measured in the study animals; DiNP was a weak agonist of whale THRB. No significant agonistic or antagonistic effects were detected for DEHP or DiNP for whale PPARG, whereas DEHP and DiNP decreased basal luciferase activity mediated by whale GR at several test concentrations. In conclusion, DEHP was detected in the blubber of marine mammals from the Norwegian Arctic and it appears to have potential to modulate the transcriptional activity of whale THRB, but current DEHP concentrations do not modulate the function of the studied nuclear receptors in adipose tissue of blue whales, fin whales, bowhead whales or polar bears sampled from the Norwegian Arctic.
2021
The Tibetan Plateau (TP), referred to as the “Asian water tower,” contains one of the largest land ice masses on Earth. The local glacier shrinkage and frozen-water storage are strongly affected by variations in surface air temperature over the TP (TPSAT), especially in springtime. This study reveals that the relationship between the February North Atlantic Oscillation (NAO) and March TPSAT is unstable with time and regulated by the phase of the Atlantic multidecadal variability (AMV). The significant out-of-phase connection occurs only during the warm phase of AMV (AMV+). The results show that during the AMV+, the negative phase of the NAO persists from February to March, and is accompanied by a quasi-stationary Rossby wave train trapped along a northward-shifted subtropical westerly jet stream across Eurasia, inducing an anomalous adiabatic descent that warms the TP. However, during the cold phase of the AMV, the negative NAO cannot persist into March. The Rossby wave train propagates along the well-separated polar and subtropical westerly jets, and the NAO–TPSAT connection is broken. Further investigation suggests that the enhanced synoptic eddy and low-frequency flow (SELF) interaction over the North Atlantic in February and March during the AMV+, caused by the southward-shifted storm track, helps maintain the NAO pattern via positive eddy feedback. This study provides a new detailed perspective on the decadal variability of the North Atlantic–TP connection in late winter to early spring.
2021
A strategy towards the generation of testable adverse outcome pathways for nanomaterials
Manufactured nanomaterials (NMs) are increasingly used in a wide range of industrial applications leading to a constant increase in the market size of nano-enabled products. The increased production and use of NMs are constantly raising concerns among different stakeholder groups with regard to their effects on human and environmental health. Currently, nanosafety hazard assessment is still widely performed using in vivo (animal) models, however the development of robust and regulatory relevant strategies is required to prioritize and/or reduce animal testing. Adverse outcome pathways (AOPs) are a structured representation of biological events that start from a molecular initiating event (MIE) leading to an adverse outcome (AO) through a series of key events (KEs). The AOP framework offers great advancement to risk assessment and regulatory safety assessments. While AOPs for chemicals have been more frequently reported, AOPs collection for NMs is narrow. By using existing AOPs, we aimed to generate simple and testable strategies to predict if a given NM has the potential to induce a MIE leading to an AO through a series of KEs. Firstly, we identified potential MIEs or initial KEs reported for NMs in the literature. Then, we searched the identified MIE or initial KEs as keywords in the AOP-Wiki to find associated AOPs. Finally, using two case studies, we demonstrated here how in vitro strategies can be used for testing the identified MIE/KEs.
2021
Elevated stratopause events in the current and a future climate: A chemistry-climate model study
The characteristics and driving mechanisms of Elevated Stratopause Events (ESEs) are examined in simulations of the ECHAM/MESSy Atmospheric Chemistry (EMAC) chemistry-climate model under present and projected climate conditions. ESEs develop after sudden stratospheric warmings (SSWs) in boreal winter. While the stratopause descends during SSWs, it is reformed at higher altitudes after the SSWs, leading to ESEs in years with a particularly high new stratopause. EMAC reproduces well the frequency and main characteristics of observed ESEs. ESEs occur in 24% of the winters, mostly after major SSWs. They develop in stable polar vortices due to a persistent tropospheric wave forcing leading to a prolonged zonal wind reversal in the lower stratosphere. By wave filtering, this enables a faster re-establishment of the mesospheric westerly jet, polar downwelling and a higher stratopause. We find the presence of a westward-propagating wavenumber-1 planetary wave in the mesosphere following the onset, consistent with in-situ generation by large-scale instability. By the end of the 21st century, the number of ESEs is projected to increase, mainly due to a sinking of the original stratopause after strong tropospheric wave forcing and planetary wave dissipation at lower levels. Future ESEs develop preferably in more intense and cold polar vortices, and tend to be shorter. While in the current climate, planetary wavenumber-2 contributes to the forcing of ESEs, future wave forcing is dominated by wavenumber-1 activity as a result of climate change. Hence, a persistent wave forcing seems to be more relevant for the development of an ESE than the wavenumber decomposition of the forcing.
2021
Emissions of Tetrafluoromethane (CF4) and Hexafluoroethane (C2F6) From East Asia: 2008 to 2019
The perfluorocarbons (PFCs), tetrafluoromethane (CF4) and hexafluoroethane (C2F6), are potent greenhouse gases with very long atmospheric lifetimes. They are emitted almost entirely from industrial sources, including the aluminum and rare earth metal smelting industries that emit them as by-products, and the semiconductor and flat panel display manufacturing industries that use them and vent unutilized amounts to the atmosphere. Despite extensive industrial efforts to quantify and curb these emissions, “top-down” PFC emission estimates derived from atmospheric measurements continue to rise and are significantly greater than reported process- and inventory-based “bottom-up” emissions. In this study, we estimate emissions of CF4 and C2F6 from East Asia, where PFC emitting industries are heavily concentrated, using a top-down approach (a Bayesian inversion) with high-frequency atmospheric measurements at Gosan (Jeju Island, South Korea) for 2008–2019. We also compile and analyze the available bottom-up CF4 and C2F6 emissions in East Asia from industrial and government reports. Our results suggest that the observed increases in global PFC emissions since 2015 are driven primarily by China's aluminum industry, with significant contributions from Japan's and Korea's semiconductor industry. Our analysis suggests that Chinese emissions occur predominantly from the aluminum industry, although their emissions per production ratio may be improving. Our results for Japan and Korea find significant discrepancies between top-down and bottom-up emissions estimates, suggesting that the effectiveness of emission reduction systems (abatement) used in their semiconductor industries may be overestimated. Overall, our top-down results for East Asia contribute significantly to reducing the gap in the global PFC emission budgets.
2021
2021
Hemispheric black carbon increase after the 13th-century Māori arrival in New Zealand
New Zealand was among the last habitable places on earth to be colonized by humans. Charcoal records indicate that wildfires were rare prior to colonization and widespread following the 13th- to 14th-century Māori settlement, but the precise timing and magnitude of associated biomass-burning emissions are unknown, as are effects on light-absorbing black carbon aerosol concentrations over the pristine Southern Ocean and Antarctica. Here we used an array of well-dated Antarctic ice-core records to show that while black carbon deposition rates were stable over continental Antarctica during the past two millennia, they were approximately threefold higher over the northern Antarctic Peninsula during the past 700 years. Aerosol modelling demonstrates that the observed deposition could result only from increased emissions poleward of 40° S—implicating fires in Tasmania, New Zealand and Patagonia—but only New Zealand palaeofire records indicate coincident increases. Rapid deposition increases started in 1297 (±30 s.d.) in the northern Antarctic Peninsula, consistent with the late 13th-century Māori settlement and New Zealand black carbon emissions of 36 (±21 2 s.d.) Gg y−1 during peak deposition in the 16th century. While charcoal and pollen records suggest earlier, climate-modulated burning in Tasmania and southern Patagonia, deposition in Antarctica shows that black carbon emissions from burning in New Zealand dwarfed other preindustrial emissions in these regions during the past 2,000 years, providing clear evidence of large-scale environmental effects associated with early human activities across the remote Southern Hemisphere.
2021
The Integrated Carbon Observation System in Europe
Since 1750, land use change and fossil fuel combustion has led to a 46 % increase in the atmospheric carbon dioxide (CO2) concentrations, causing global warming with substantial societal consequences. The Paris Agreement aims to limiting global temperature increases to well below 2°C above pre-industrial levels. Increasing levels of CO2 and other greenhouse gases (GHGs), such as methane (CH4) and nitrous oxide (N2O), in the atmosphere are the primary cause of climate change. Approximately half of the carbon emissions to the atmosphere is sequestered by ocean and land sinks, leading to ocean acidification but also slowing the rate of global warming. However, there are significant uncertainties in the future global warming scenarios due to uncertainties in the size, nature and stability of these sinks. Quantifying and monitoring the size and timing of natural sinks and the impact of climate change on ecosystems are important information to guide policy-makers’ decisions and strategies on reductions in emissions. Continuous, long-term observations are required to quantify GHG emissions, sinks, and their impacts on Earth systems. The Integrated Carbon Observation System (ICOS) was designed as the European in situ observation and information system to support science and society in their efforts to mitigate climate change. It provides standardized and open data currently from over 140 measurement stations across 12 European countries. The stations observe GHG concentrations in the atmosphere and carbon and GHG fluxes between the atmosphere, land surface and the oceans. This article describes how ICOS fulfills its mission to harmonize these observations, ensure the related long-term financial commitments, provide easy access to well-documented and reproducible high-quality data and related protocols and tools for scientific studies, and deliver information and GHG-related products to stakeholders in society and policy.
2021
2021
DNA damage in circulating leukocytes measured with the comet assay may predict the risk of death
The comet assay or single cell gel electrophoresis, is the most common method used to measure strand breaks and a variety of other DNA lesions in human populations. To estimate the risk of overall mortality, mortality by cause, and cancer incidence associated to DNA damage, a cohort of 2,403 healthy individuals (25,978 person-years) screened in 16 laboratories using the comet assay between 1996 and 2016 was followed-up. Kaplan–Meier analysis indicated a worse overall survival in the medium and high tertile of DNA damage (p < 0.001). The effect of DNA damage on survival was modelled according to Cox proportional hazard regression model. The adjusted hazard ratio (HR) was 1.42 (1.06–1.90) for overall mortality, and 1.94 (1.04–3.59) for diseases of the circulatory system in subjects with the highest tertile of DNA damage. The findings of this study provide epidemiological evidence encouraging the implementation of the comet assay in preventive strategies for non-communicable diseases.
2021
Calibration of CO, NO2, and O3 Using Airify: A Low-Cost Sensor Cluster for Air Quality Monitoring
During the last decade, extensive research has been carried out on the subject of low-cost sensor platforms for air quality monitoring. A key aspect when deploying such systems is the quality of the measured data. Calibration is especially important to improve the data quality of low-cost air monitoring devices. The measured data quality must comply with regulations issued by national or international authorities in order to be used for regulatory purposes. This work discusses the challenges and methods suitable for calibrating a low-cost sensor platform developed by our group, Airify, that has a unit cost five times less expensive than the state-of-the-art solutions (approximately €1000). The evaluated platform can integrate a wide variety of sensors capable of measuring up to 12 parameters, including the regulatory pollutants defined in the European Directive. In this work, we developed new calibration models (multivariate linear regression and random forest) and evaluated their effectiveness in meeting the data quality objective (DQO) for the following parameters: carbon monoxide (CO), ozone (O3), and nitrogen dioxide (NO2). The experimental results show that the proposed calibration managed an improvement of 12% for the CO and O3 gases and a similar accuracy for the NO2 gas compared to similar state-of-the-art studies. The evaluated parameters had different calibration accuracies due to the non-identical levels of gas concentration at which the sensors were exposed during the model’s training phase. After the calibration algorithms were applied to the evaluated platform, its performance met the DQO criteria despite the overall low price level of the platform.
2021
There are large knowledge gaps concerning environmental levels and fate of many organic pollutants, particularly for chemicals of emerging concern in tropical regions of the Global South. In this study, we investigated the levels of chlorinated paraffins (CPs) and dechloranes in air and soil in rural, suburban, and urban regions in and around Dar es Salaam, Tanzania. Samples were also collected near the city's main municipal waste dumpsite and an electronic waste (e-waste) handling facility. In passive air samples, short chain CPs (SCCPs) dominated, with an average estimated concentration of 22 ng/m3, while medium chain CPs (MCCPs) had an average estimated concentration of 9 ng/m3. The average estimated air concentration of ∑dechloranes (Dechlorane Plus (DP) + Dechlorane 602 + Dechlorane 603) was three to four orders of magnitudes lower, 2 pg/m3. In soil samples, MCCPs dominated with an average concentration of 640 ng/g dw, followed by SCCPs with an average concentration of 330 ng/g dw, and ∑dechloranes with an average concentration of 0.9 ng/g dw. In both air and soil, DP was the dominating dechlorane compound. Urban pulses were observed for CPs and dechloranes in air and soil. CPs were in addition found in elevated levels at the municipal waste dumpsite and the e-waste handling facility, while DPs were found in elevated levels at the e-waste handling facility. This suggests that waste handling sites represent important emission sources for these pollutants. Investigations into seasonal trends and environmental fate of CPs and dechloranes showed that monsoonal rain patterns play a major role in governing air concentrations and mobility, particularly for the less volatile MCCPs and dechloranes. This study is the first to report levels of CPs in air from sub-Saharan Africa, and DP, Dechlorane 602, and Dechlorane 603 in soil from sub-Saharan Africa.
2021
The effect of the 2018 extreme meteorological conditions in Europe on methane (CH4) emissions is examined using estimates from four atmospheric inversions calculated for the period 2005–2018. For most of Europe, we find no anomaly in 2018 compared to the 2005–2018 mean. However, we find a positive anomaly for the Netherlands in April, which coincided with positive temperature and soil moisture anomalies suggesting an increase in biogenic sources. We also find a negative anomaly for the Netherlands for September–October, which coincided with a negative anomaly in soil moisture, suggesting a decrease in soil sources. In addition, we find a positive anomaly for Serbia in spring, summer and autumn, which coincided with increases in temperature and soil moisture, again suggestive of changes in biogenic sources, and the annual emission for 2018 was 33 ± 38% higher than the 2005–2017 mean. These results indicate that CH4 emissions from areas where the natural source is thought to be relatively small can still vary due to meteorological conditions. At the European scale though, the degree of variability over 2005–2018 was small, and there was negligible impact on the annual CH4 emissions in 2018 despite the extreme meteorological conditions.
This article is part of a discussion meeting issue ‘Rising methane: is warming feeding warming? (part 2)’.
2021
As the leading climate mode of wintertime climate variability over Europe, the North Atlantic Oscillation (NAO) has been extensively studied over the last decades. Recently, studies highlighted the state of the Eurasian cryosphere as a possible predictor for the wintertime NAO. However, missing correlation between snow cover and wintertime NAO in climate model experiments and strong non-stationarity of this link in reanalysis data are questioning the causality of this relationship.
Here we use the large ensemble of Atmospheric Seasonal Forecasts of the 20th Century (ASF-20C) with the European Centre for Medium-Range Weather Forecasts model, focusing on the winter season. Besides the main 110-year ensemble of 51 members, we investigate a second, perturbed ensemble of 21 members where initial (November) land conditions over the Northern Hemisphere are swapped from neighboring years. The Eurasian snow–NAO linkage is examined in terms of a longitudinal snow depth dipole across Eurasia. Subsampling the perturbed forecast ensemble and contrasting members with high and low initial snow dipole conditions, we found that their composite difference indicates more negative NAO states in the following winter (DJF) after positive west-to-east snow depth gradients at the beginning of November. Surface and atmospheric forecast anomalies through the troposphere and stratosphere associated with the anomalous positive snow dipole consist of colder early winter surface temperatures over eastern Eurasia, an enhanced Ural ridge and increased vertical energy fluxes into the stratosphere, with a subsequent negative NAO-like signature in the troposphere. We thus confirm the existence of a causal connection between autumn snow patterns and subsequent winter circulation in the ASF-20C forecasting system.
2021
The historical (1835–2020) dry deposition of major air pollutants (SO2, NOx, O3 and PM2.5) in the urban background in Oslo, Norway, in a situation that could represent the building facades, was approximated from reported fuel combustion, emission factors, air concentrations since 1960, and dry deposition velocities. The annual accumulated dry deposition (and thus not considering the removal processes) of the pollutants, together, was found to have varied from about 2.3 to 27 g m−2, with the maximum in the 1960s caused by high SO2 emissions from the combustion of fuel oils, and with 1.6 kg m−2 having deposited over all the years. The deposition of PM2.5 was found to have dominated from 1835, have increased to a maximum in 1875 and then slowly decreased. The SO2 deposition decreased to a low value around 1990. The NOx deposition was also at its highest in the 1960s to about 1970, it became the largest from the 1980s, and then showed a clear decrease from about 2010. The O3 deposition was lower in the years of the maximum total and NOx deposition. The dry deposition of O3 and NOx were found to be about similar in 2020, more than two times that of PM2.5 and more than four times that of SO2. The trends of the NOx emissions were found to reflect the relative (1975) and absolute (∼2000) turning points of the environmental Kuznets curves (EKC) that has been suggested for Norway, whereas the trend of the SO2 emissions seems to have “shortcut” this development by the strong regulations in the emissions from 1970 that lead to near simultaneous relative and absolute reductions. The gradual decrease of the PM2.5 emissions from about 1945 seems to correspond with the decrease in combustion energy intensity in the economy as wood was substituted with more energy efficient fuels and then with the continued reduction in the wood burning.
2021
DNA Repair Gene Polymorphisms and Chromosomal Aberrations in Exposed Populations
DNA damage and unrepaired or insufficiently repaired DNA double-strand breaks as well as telomere shortening contribute to the formation of structural chromosomal aberrations (CAs). Non-specific CAs have been used in the monitoring of individuals exposed to potential carcinogenic chemicals and radiation. The frequency of CAs in peripheral blood lymphocytes (PBLs) has been associated with cancer risk and the association has also been found in incident cancer patients. CAs include chromosome-type aberrations (CSAs) and chromatid-type aberrations (CTAs) and their sum CAtot. In the present study, we used data from our published genome-wide association studies (GWASs) and extracted the results for 153 DNA repair genes for 607 persons who had occupational exposure to diverse harmful substances/radiation and/or personal exposure to tobacco smoking. The analyses were conducted using linear and logistic regression models to study the association of DNA repair gene polymorphisms with CAs. Considering an arbitrary cutoff level of 5 × 10–3, 14 loci passed the threshold, and included 7 repair pathways for CTA, 4 for CSA, and 3 for CAtot; 10 SNPs were eQTLs influencing the expression of the target repair gene. For the base excision repair pathway, the implicated genes PARP1 and PARP2 encode poly(ADP-ribosyl) transferases with multiple regulatory functions. PARP1 and PARP2 have an important role in maintaining genome stability through diverse mechanisms. Other candidate genes with known roles for CSAs included GTF2H (general transcription factor IIH subunits 4 and 5), Fanconi anemia pathway genes, and PMS2, a mismatch repair gene. The present results suggest pathways with mechanistic rationale for the formation of CAs and emphasize the need to further develop techniques for measuring individual sensitivity to genotoxic exposure.
2021
The rise of advanced ICT technologies has made it possible to apply low-cost sensor systems for measuring air quality in citizen science projects, including education. High school students in Norway used these sensor systems in a citizen science project to design, carry out, and evaluate their own research projects on air quality. An impact assessment framework was designed to assess the impact of these activities, considering five areas of impact: scientific, social, economic, political, and environmental. In addition, the framework also considers the transformative potential of the citizen science pilot, i.e., the degree to which the pilot can help to change, alter, or replace current systems, and the business-as-usual in one or more fields such as knowledge production or environmental protection. Data for this assessment were gathered in the form of questionnaires that the students had to complete before starting and after finalizing the pilot activities. The results showed positive impacts on learning, a pro-environmental world view, and an increase in pro-science attitudes and interest in scientific and environmental-related topics at the end of the pilot activities. Only weak impacts were measured for behavioral change. The activities showed transformative potential, which makes the student activities an example of good practice for citizen science activities on air quality with low-cost sensors.
2021
How Atmospheric Chemistry and Transport Drive Surface Variability of N2O and CFC-11
Nitrous oxide (N2O) is a long-lived greenhouse gas that affects atmospheric chemistry and climate. In this work, we use satellite measurements of N2O, ozone (O3), and temperature from the Aura Microwave Limb Sounder (MLS) instrument to calculate stratospheric loss of N2O, and thus its atmospheric lifetime. Using three chemistry transport models simulating the Aura period 2005–2017, we verify the stratospheric sink using MLS data and follow that loss signal down to the surface and compare with surface observations. Stratospheric loss has a strong seasonal cycle and is further modulated by the Quasi-Biennial Oscillation (QBO); these cycles are seen equally in both observations and the models. When filtered for interannual variability, the modeled surface signal is QBO-caused, and it reproduces the observed pattern, highlighting the potential role of the QBO in tropospheric chemistry and composition, as well as in model evaluation. The observed annual surface signal in the northern hemisphere matches well with the models run without emissions, indicating the annual cycle is driven mostly by stratosphere-troposphere exchange (STE) flux of N2O-depleted air and not surface N2O emissions. In the southern hemisphere (SH), all three models disagree and thus provide no guidance, except for indicating that modeling annual STE in the SH remains a major model uncertainty. Parallel model simulations of CFCl3, which has greater stratospheric loss that N2O and possibly surreptitious emissions, show that its interannual variations parallel those of N2O, and thus the observed N2O variability can identify the stratospheric component of the observed CFCl3 variability.
2021
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
Low-risk removal of embedded surface soiling on delicate heritage objects can require novel alternatives to traditional cleaning systems. Edvard Munch’s monumental Aula paintings (1911–16) have a long history of exposure to atmospheric pollution and cleaning campaigns that have compromised the appearance and the condition of these important artworks. Soiling removal from porous and water-sensitive, unvarnished oil paintings continues to be a major conservation challenge. This paper presents the approach and results of research into the effect and efficiency of three novel systems used for soiling removal: soft particle blasting, CO2-snow blasting, and Nanorestore Gel® Dry and Peggy series hydrogels. Cleaning tests were performed on accelerated-aged and artificially soiled mock-ups consisting of unvarnished oil paint and chalk-glue grounds. Visual and analytical assessment (magnification using a light microscope and scanning electron microscope, as well as colour- and gloss measurement) was carried out before and after mock-up cleaning tests and the results were compared to those obtained using the dry polyurethane sponges employed in the most recent Aula surface cleaning campaign (2009–11). Although the results varied, the Nanorestore Gel® series proved promising with respect to improved soiling removal efficiency, and reduced pigment loss for the water-sensitive surfaces evaluated, compared to dry sponges.
2021
Assessing the impacts of citizen-led policies on emissions, air quality and health
Air pollution is a global challenge, and especially urban areas are particularly affected by acute episodes. Traditional approaches used to mitigate air pollution primarily consider the technical aspects of the problem but not the role of citizen behaviour and day-to-day practices. ClairCity, a Horizon 2020 funded project, created an impact assessment framework considering the role of citizen behaviour to create future scenarios, aiming to improve urban environments and the wellbeing and health of its inhabitants. This framework was applied to six pilot cases: Bristol, Amsterdam, Ljubljana, Sosnowiec, Aveiro Region and Liguria Region, considering three-time horizons: 2025, 2035 and 2050. The scenarios approach includes the Business As Usual (BAU) scenario and a Final Unified Policy Scenarios (FUPS) established by citizens, decision-makers, local planners and stakeholders based on data collected through a citizen and stakeholder co-creation process. Therefore, this paper aims to present the ClairCity outcomes, analysing the quantified impacts of selected measures in terms of emissions, air quality, population exposure, and health. Each case study has established a particular set of measures with different levels of ambition, therefore different levels of success were achieved towards the control and mitigation of their specific air pollution problems. The transport sector was the most addressed by the measures showing substantial improvements for NO2, already with the BAU scenarios, and overall, even better results when applying the citizen-led FUPS scenarios. In some cases, due to a lack of ambition for the residential and commercial sector, the results were not sufficient to fulfil the WHO guidelines. Overall, it was found in all cities that the co-created scenarios would lead to environmental improvements in terms of air quality and citizens’ health compared to the baseline year of 2015. However, in some cases, the health impacts were lower than air quality due to the implementation of the measures not affecting the most densely populated areas. Benefits from the FUPS comparing to the BAU scenario were found to be highest in Amsterdam and Bristol, with further NO2 and PM10 emission reductions around 10%–16% by 2025 and 19%–28% by 2050, compared to BAU.
2021
Global predictions of primary soil salinization under changing climate in the 21st century
Soil salinization has become one of the major environmental and socioeconomic issues globally and this is expected to be exacerbated further with projected climatic change. Determining how climate change influences the dynamics of naturally-occurring soil salinization has scarcely been addressed due to highly complex processes influencing salinization. This paper sets out to address this long-standing challenge by developing data-driven models capable of predicting primary (naturally-occurring) soil salinity and its variations in the world’s drylands up to the year 2100 under changing climate. Analysis of the future predictions made here identifies the dryland areas of South America, southern and western Australia, Mexico, southwest United States, and South Africa as the salinization hotspots. Conversely, we project a decrease in the soil salinity of the drylands in the northwest United States, the Horn of Africa, Eastern Europe, Turkmenistan, and west Kazakhstan in response to climate change over the same period.
2021
Brominated Flame Retardants in Antarctic Air in the Vicinity of Two All-Year Research Stations
Continuous atmospheric sampling was conducted between 2010–2015 at Casey station in Wilkes Land, Antarctica, and throughout 2013 at Troll Station in Dronning Maud Land, Antarctica. Sample extracts were analyzed for polybrominated diphenyl ethers (PBDEs), and the naturally converted brominated compound, 2,4,6-Tribromoanisole, to explore regional profiles. This represents the first report of seasonal resolution of PBDEs in the Antarctic atmosphere, and we describe conspicuous differences in the ambient atmospheric concentrations of brominated compounds observed between the two stations. Notably, levels of BDE-47 detected at Troll station were higher than those previously detected in the Antarctic or Southern Ocean region, with a maximum concentration of 7800 fg/m3. Elevated levels of penta-formulation PBDE congeners at Troll coincided with local building activities and subsided in the months following completion of activities. The latter provides important information for managers of National Antarctic Programs for preventing the release of persistent, bioaccumulative, and toxic substances in Antarctica.
2021