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Laura Huilaja,1,* Eeva Bur,2,* Jari Jokelainen,3 Suvi-Päivikki Sinikumpu,1 Petri Kulmala2,4 1Department of Dermatology and Medical Research Center Oulu, PEDEGO Research Unit, University of Oulu and Oulu University Hospital, Oulu, Finland; 2Faculty of Medicine, University of Oulu, Oulu, Finland; 3Infrastructure for Population Studies, Faculty of Medicine, University of Oulu, Oulu, Finland; 4Department of Pediatrics and Medical Research Center Oulu, PEDEGO Research Unit, University of Oulu and Oulu University Hospital, Oulu, Finland*These authors contributed equally to this workCorrespondence: Laura Huilaja, Email laura.huilaja@oulu.fiBackground: Today’s professionals need to be capable of independent information retrieval, teamwork, and lifelong learning. To meet these demands, more active learning methods are needed in university teaching. Team-based learning (TBL) is a learner-centered method which enables activation of students in large classes.Objective: The aim of this study was to compare a method combining peer teaching and TBL (peer-conducted TBL; pTBL) with faculty-led seminar teaching. More precisely, students’ opinions about teaching methods and immediate and long-term learning outcomes were aimed to compare.Methods: A faculty-led design was compared to a pTBL design when teaching pediatric and dermatological allergy in a seminar setting for 5th year medical students. For that purpose, students were randomly split into two learning groups. In a faculty-led seminar (n = 44 students) the instructor first lectured on each subject; then, named students from each group were asked to present clinical cases given to them beforehand and them raising questions were answered. In a pTBL group (n = 50) student’s prior knowledge was first tested. Then, randomly selected, pre-prepared students took a tutors role in a seminar and presented clinical case to be solved in groups by all students. Students’ performance was equally tested after both sessions and 5– 6 months afterwards. Students’ opinions were asked by an electronic survey.Results: In this study, pTBL was significantly preferred over faculty-led learning (mean grade 8.5 vs 6.5). Those participating in pTBL group studied pre-learning material more actively than those in faculty-led group. However, there was no difference in learning outcomes (immediate or long term) between the groups.Conclusion: Students prefer teaching method in which they are self in active role. Combining TBL and peer teaching may further increase the accumulation of non-academic skills like expertise and proficiency.Keywords: peer teaching, team-based learning, active learning

Linda Litwin,1,2 Johnny KM Sundholm,1,3 Jelena Meinilä,4 Janne Kulmala,5 Tuija H Tammelin,5 Kristiina Rönö,6 Saila B Koivusalo,6 Johan G Eriksson,7– 10 Taisto Sarkola1,3 1Children’s Hospital, University of Helsinki and Helsinki University Hospital, Helsinki, Finland; 2Department of Congenital Heart Defects and Pediatric Cardiology, FMS in Zabrze, Medical University of Silesia, Katowice, Poland; 3Minerva Foundation Institute for Medical Research, Helsinki, Finland; 4Department of Food and Nutrition, University of Helsinki, Helsinki, Finland; 5LIKES Research Centre for Physical Activity and Health, Jyväskylä, Finland; 6Women’s Hospital, University of Helsinki and Helsinki University Hospital, Helsinki, Finland; 7Folkhälsan Research Center, Helsinki, Finland; 8Department of General Practice and Primary Health Care, University of Helsinki and Helsinki University Hospital, Helsinki, Finland; 9Human Potential Translational Research Programme and Department of Obstetrics and Gynaecology, Yong Loo Lin School of Medicine, National University Singapore, Singapore; 10Singapore Institute for Clinical Sciences (SICS), Agency for Science, Technology and Research (A*STAR), SingaporeCorrespondence: Linda LitwinDepartment of Congenital Heart Defects and Pediatric Cardiology, FMS in Zabrze, Medical University of Silesia, M.Sklodowskiej-Curie 9, Zabrze, 41-800, PolandTel +48 322713401Fax +48 322713401Email linda.litwin@med.sum.edu.plBackground: Heredity and family-shared lifestyle contribute to cardiovascular risk, but the magnitude of their influence on arterial structure and function in early childhood is unknown. We aimed to assess associations between child and maternal ideal cardiovascular health, maternal subclinical atherosclerosis, and child arterial phenotype.Methods: Cross-sectional analysis of 201 mother-child pairs originating from the Finnish Gestational Diabetes Prevention Study (RADIEL) longitudinal cohort was done at child age 6.1 ± 0.5 years with assessments of ideal cardiovascular health (BMI, blood pressure, fasting glucose, total cholesterol, diet quality, physical activity, smoking), body composition, very-high frequency ultrasound of carotid arteries (25 and 35 MHz), and pulse wave velocity.Results: We found no association between child and maternal ideal cardiovascular health but report evidence of particular metrics correlations: total cholesterol (r=0.24, P=0.003), BMI (r=0.17, P=0.02), diastolic blood pressure (r=0.15, P=0.03), and diet quality (r=0.22, P=0.002). Child arterial phenotype was not associated with child or maternal ideal cardiovascular health. In the multivariable regression explanatory model adjusted for child sex, age, systolic blood pressure, lean body mass, and body fat percentage, child carotid intima-media thickness was independently associated only with maternal carotid intima-media thickness (0.1 mm increase [95% CI 0.05, 0.21, P=0.001] for each 1 mm increase in maternal carotid intima-media thickness). Children of mothers with subclinical atherosclerosis had decreased carotid artery distensibility (1.1 ± 0.2 vs 1.2 ± 0.2%/10 mmHg, P=0.01) and trend toward increased carotid intima-media thickness (0.37 ± 0.04 vs 0.35 ± 0.04 mm, P=0.06).Conclusion: Ideal Cardiovascular Health metrics are heterogeneously associated in mother-child pairs in early childhood. We found no evidence of child or maternal Ideal Cardiovascular Health effect on child arterial phenotype. Maternal carotid intima-media thickness predicts child carotid intima-media thickness, but the underlying mechanisms remain unclear. Maternal subclinical atherosclerosis is associated with local carotid arterial stiffness in early childhood.Keywords: cardiovascular disease, atherosclerosis, carotid intima-media thickness, risk factor, child

Background: Physical activity (PA) may benefit academic performance, but it is unclear what kind of classroom-based PA is optimal for learning. Aim: We studied the effects of physically active maths lessons on children's maths performance and maths-related effects, and whether gender and previous mathematical or motor skills modify these effects. Sample: A total of 22 volunteered teachers and their pupils with signed consent (N = 397, mean age: 9.3 years, 51% females) participated in a 5-month, teacher-led, multi-arm, cluster-randomized controlled trial. Methods: The intervention included a PAL group (20 min of physically active learning in each 45-min lesson), a breaks group (two 5-min PA breaks in each 45-min lesson) and a control group (traditional teaching). Maths performance was assessed with a tailored curriculum-based test. Maths-related enjoyment, self-perceptions and anxiety were measured with a self-reported questionnaire. The individual-level intervention effects were tested via covariate-adjusted linear mixed-effect models with school classes serving as random effects. Results: Changes in maths performance or self-perceptions did not differ between the intervention groups. Maths anxiety in learning situations increased in the PAL group (effect .28, 95% CI = .01--.56); there was no change in the other groups. Subgroup analyses suggested that maths anxiety increased in the PAL group among children in the two lowest tertiles of motor skills. It decreased in the highest tertile. Enjoyment decreased in the breaks group among pupils in the lowest motor skill tertile. Conclusions: Physically active maths lessons did not affect maths performance or self-perceptions but had divergent effects on maths anxiety and enjoyment, depending on motor skills.

The aim of the study was to assess patient dose from whole-body computed tomography (CT) in association with patient size, automatic exposure control (AEC) and intravenous (IV) contrast agent.

In this study, we present and analyze the first continuous time series of relevant aerosol precursor vapors from the central Arctic (north of 80° N) during the Multidisciplinary drifting Observatory for the Study of Arctic Climate (MOSAiC) expedition. These precursor vapors include sulfuric acid (SA), methanesulfonic acid (MSA), and iodic acid (IA). We use FLEXPART simulations, inverse modeling, sulfur dioxide (SO2) mixing ratios, and chlorophyll a (chl a) observations to interpret the seasonal variability in the vapor concentrations and identify dominant sources. Our results show that both natural and anthropogenic sources are relevant for the concentrations of SA in the Arctic, but anthropogenic sources associated with Arctic haze are the most prevalent. MSA concentrations are an order of magnitude higher during polar day than during polar night due to seasonal changes in biological activity. Peak MSA concentrations were observed in May, which corresponds with the timing of the annual peak in chl a concentrations north of 75° N. IA concentrations exhibit two distinct peaks during the year, namely a dominant peak in spring and a secondary peak in autumn, suggesting that seasonal IA concentrations depend on both solar radiation and sea ice conditions. In general, the seasonal cycles of SA, MSA, and IA in the central Arctic Ocean are related to sea ice conditions, and we expect that changes in the Arctic environment will affect the concentrations of these vapors in the future. The magnitude of these changes and the subsequent influence on aerosol processes remains uncertain, highlighting the need for continued observations of these precursor vapors in the Arctic.

Cloud properties are strongly influenced by ice formation; hence, we need to understand the sources of ice-nucleating particles (INPs) around the globe. Boreal forests are known as sources of bioaerosol, and recent work indicates that these dominate the INP spectra above −24 °C. To quantify the INP population at temperatures below −24 °C, we deployed a portable cloud expansion chamber (PINE) in a Finnish boreal forest from 13 March 2018 to 11 May 2018. Using the 6 min time resolution PINE data, we present several lines of evidence that INPs below −24 °C in this location are also from biological sources: (i) an INP parameterization developed for a pine forest site in Colorado, where many INPs were shown to be biological, produced a good fit to our measurements; a moderate correlation of INPs with aerosol concentration larger than 0.5 µm and the fluorescent bioaerosol concentration; (ii) a negative correlation with relative humidity that may relate to enhanced release of bioaerosol at low humidity from local sources such as the prolific lichen population in boreal forests; and (iii) the absence of correlation with ultra-fine particles (3.5 to 50 nm), indicating that new particle formation events are not sources of INPs. This study should motivate further work to establish whether the commonality in bioaerosol ice-nucleating properties between spring in Finland and summer in Colorado is more generally applicable to different coniferous forest locations and times and also to determine to what extent these bioaerosols are transported to locations where they may affect clouds.

The Cluster Ion Counter (CIC) is a simple three-channel instrument designed to observe ions in the electrical mobility equivalent diameter range from 1.0 to 5 nm. With the three channels, we can observe concentrations of both ion clusters (sub-2 nm ions) and intermediate ions. Furthermore, as derived here, we can estimate condensation sink (CS), intensity of local new particle formation, growth rate of newly formed particles from 2 to 3 nm and formation rate of 2 nm ions. We compared CIC measurements with those of a multichannel ion spectrometer, the Neutral cluster and Air Ion Spectrometer (NAIS), and found that the concentrations agreed well between the two instruments, with correlation coefficients of 0.89 and 0.86 for sub-2 nm and 2.0–2.3 nm ions, respectively. According to the observations made in Hyytiälä, Finland, and Beijing, China, the ion source rate was estimated to be about two to four ion pairs cm−3 s−1. The new CIC is a simple and cheap instrument that can be used in different environments to obtain information about small ion dynamics, local intermediate ion formation and CS in a robust way when combined with the theoretical framework presented here.

Ice nucleating particles (INPs) play a crucial role in initiating ice crystal formation in clouds, influencing the dynamics and optical properties of clouds and their impacts on precipitation and the climate system. Despite their importance, there is limited knowledge about the vertical distribution of INPs. This study focuses on aircraft measurements conducted during spring 2018 above the boreal forest of Hyytiälä, Finland. Similarities between INP concentrations, activated fractions, particle concentrations, and size distributions observed at ground level and in the boundary layer aloft indicate that surface particles and INPs are efficiently transported and mixed within the boundary layer. INP concentrations observed in the boundary layer are best predicted by a parameterization describing near-surface INP concentrations driven by the abundance of biogenic aerosol in the Finnish boreal forest, suggesting that biogenic INPs are dominant in the boundary layer above the same environment. Most of the INP concentrations and activated fractions observed in the free troposphere are notably lower than in the boundary layer, and the distinct particle size distributions suggest that different aerosol populations, likely resulting from long-range transport, are present in the free troposphere. However, we show one case where higher INP concentrations are observed in the free troposphere and where a homogeneous particle population exists from the surface to the free troposphere. This indicates that surface particles and INPs from the boreal forest can occasionally reach the free troposphere, which is particularly important as the INPs in the free troposphere can further travel horizontally and/or vertically and impact cloud formation.

The number of studies on the effects of mindfulness on healthcare professionals is increasing. The main aim of this study was to collate the quantitative results of original studies analyzing the effects of mindfulness-based interventions on a variety of outcomes in medical students. We also analyzed how the study design and characteristics of the intervention affect the results, and identified qualitative effects of mindfulness interventions. A literature search was performed in different databases in June 2020. Original articles meeting the following criteria were included: (1) at least 50% of the participants were medical students, (2) included a mindfulness intervention, (3) analyzed any outcome relating to mindfulness intervention, (4) peer-reviewed (5) written in English. Eventually, 31 articles including 24 different samples were included. Over half of the studies were RCTs. In over half of the studies, the intervention was 4- to 10-week original Mindfulness-Based Stress Reduction or Mindfulness-Based Cognitive Therapy or a modification of these. In general, satisfaction with the interventions was good. Based on a meta-analysis, after the intervention, the intervention group had statistically significantly fewer symptoms of stress and distress and had higher mindfulness than the controls. The beneficial effects persisted in follow-ups over months or years. Both long and shorter courses and courses with and without face-to-face sessions were effective. Both controlled and uncontrolled studies had statistically significant results. Qualitative results revealed potential factors behind the quantitative effects. The number of studies on mindfulness interventions in medical students has increased drastically. Mindfulness-based interventions seem to offer a good possibility to enhance medical students' well-being.

Establishment of the SMEAR Estonia at a hemiboreal mixed deciduous broad-leaved-evergreen needle-leaved forest at Järvselja, South-Eastern Estonia, has strongly enhanced the possibilities for national and international cooperation in the fields of forest ecosystem – atmosphere research and impacts of climatic changes on forest ecosystems, atmospheric trace gases, aerosols and air ions. The station provides a multitude of comprehensive continuously measured data covering key climatic and atmospheric characteristics (state and dynamics of solar radiation, trace gases, aerosols and air ions, meteorological parameters) and forest ecosystem traits (net primary productivity, individual tree growth, gas-exchange characteristics, soil variables). The station follows a multidisciplinary and multiscale approach covering processes in spatial dimensions ranging from nanometres to several hundred square kilometres, being thus able to significantly contribute to worldwide measurement networks and the SMEAR network. Here we present an overview of the station, its data produced and we envision future developments towards sustainable research and development of the large-scale scientific infrastructure SMEAR Estonia.

As an important source of sub-micrometer particles, atmospheric new particle formation (NPF) has been observed in various environments. However, most studies provide little more than snapshots of the NPF process due to their underlying observations being limited in space and time. To obtain statistically relevant evidence on NPF across various environments, we investigated the characteristics of NPF based on a 5-year dataset of the German Ultrafine Aerosol Network (GUAN). The results were also compared with observations in previous studies, with the aim to depict a relatively complete picture of NPF in central Europe. The highest NPF occurrence frequency was observed in regional background sites, with an average of about 19 %, followed by urban background (15 %), low-mountain-range (7 %), and high Alpine (3 %) sites. The annual mean growth rate between 10 and 25 nm varied from 3.7–4.7 nm h−1, while the formation rate with same size range 10–25 nm from 0.4 to 2.9 cm−3 s−1. The contribution of NPF to ultrafine particles (UFPs) was about 13 %, 21 %, and 7 % for the urban background, regional background, and low mountain range, respectively. The influence of NPF on cloud condensation nuclei (CCN) number concentration and the aerosol extinction coefficient for NPF days was the highest in mountainous areas. These findings underscore the importance of local environments when assessing the potential impact of NPF on regional climate in models, and they also emphasize the usefulness of a long-term aerosol measurement network for understanding the variation in NPF features and their influencing factors over a regional scale.

Abstract During summer, ammonia emissions in Southeast Asia influence air pollution and cloud formation. Convective transport by the South Asian monsoon carries these pollutant air masses into the upper troposphere and lower stratosphere (UTLS), where they accumulate under anticyclonic flow conditions. This air mass accumulation is thought to contribute to particle formation and the development of the Asian Tropopause Aerosol Layer (ATAL). Despite the known influence of ammonia and particulate ammonium on air pollution, a comprehensive understanding of the ATAL is lacking. In this modelling study, the influence of ammonia on particle formation is assessed with emphasis on the ATAL. We use the EMAC chemistry-climate model, incorporating new particle formation parameterisations derived from experiments at the CERN CLOUD chamber. Our diurnal cycle analysis confirms that new particle formation mainly occurs during daylight, with a 10-fold enhancement in rate. This increase is prominent in the South Asian monsoon UTLS, where deep convection introduces high ammonia levels from the boundary layer, compared to a baseline scenario without ammonia. Our model simulations reveal that this ammonia-driven particle formation and growth contributes to an increase of up to 80% in cloud condensation nuclei (CCN) concentrations at cloud-forming heights in the South Asian monsoon region. We find that ammonia profoundly influences the aerosol mass and composition in the ATAL through particle growth, as indicated by an order of magnitude increase in nitrate levels linked to ammonia emissions. However, the effect of ammonia-driven new particle formation on aerosol mass in the ATAL is relatively small. Ammonia emissions enhance the regional aerosol optical depth (AOD) for shortwave solar radiation by up to 70%. We conclude that ammonia has a pronounced effect on the ATAL development, composition, the regional AOD, and CCN concentrations.

Nitrous acid (HONO) is an important precursor of OH radicals which affects not only the sinks of primary air pollutants but also the formation of secondary air pollutants, but its source closure in the atmosphere is still controversial due to a lack of experiment validation. In this study, the HONO budget in Beijing has been analyzed and validated through the coronavirus disease (COVID-19) lockdown event, which resulted in a significant reduction in air pollutant emissions, providing a rare opportunity to understand the HONO budget in the atmosphere. We measured HONO and related pollutants from 1 January to 6 March 2020, which covered the Chinese New Year (CNY) and the COVID-19 lockdown. The average concentration of HONO decreased from 0.97 ± 0.74 ppb before CNY to 0.53 ± 0.44 ppb during the COVID-19 lockdown, accompanied by a sharp drop in NOx and the greatest drop in NO (around 87 %). HONO budget analysis suggests that vehicle emissions were the most important source of HONO during the nighttime (53 ± 17 %) before CNY, well supported by the decline in their contribution to HONO during the COVID-19 lockdown. We found that the heterogeneous conversion of NO2 on ground surfaces was an important nighttime source of HONO (31 ± 5 %), while that on aerosol surfaces was a minor source (2 ± 1 %). Nitrate photolysis became the most important daytime source during the COVID-19 lockdown compared with that before CNY, resulting from the combined effect of the increase in nitrate and the decrease in NO. Our results indicate that reducing vehicle emissions should be an effective measure for alleviating HONO in Beijing.

Despite the numerous studies on year-to-year variation of tree growth, the physiological mechanisms controlling annual variation in growth are still not understood in detail. We studied the applicability of data-driven approach i.e. different regression models in analysing high-dimensional data set including continuous and comprehensive measurements over meteorology, ecosystem-scale water and carbon fluxes and the annual variation in the growth of app. 50-year-old Scots pine stand in southern Finland. Even though our dataset covered only 16 years, it is the most extensive collection of interactions between a Scots pine ecosystem and atmosphere. The analysis revealed that height growth was favoured by high water potential of the tree and carbon gain during the bud forming period and high water potential during the elongation period. Diameter growth seemed to be favoured by a winter with high precipitation and deep snow cover and a spring with high carbon gain. The obtained models had low generalization performance and they would require more evaluation and iterative validation to achieve credibility perhaps as a mixture of data-driven and first principle modeling approaches.

Abstract Background Mammalian display is an appealing technology for therapeutic antibody development. Despite the advantages of mammalian display, such as full-length IgG display with mammalian glycosylation and its inherent ability to select antibodies with good biophysical properties, the restricted library size and large culture volumes remain challenges. Bxb1 serine integrase is commonly used for the stable genomic integration of antibody genes into mammalian cells, but presently lacks the efficiency required for the display of large mammalian display libraries. To increase the Bxb1 integrase-mediated stable integration efficiency, our study investigates factors that potentially affect the nuclear localization of Bxb1 integrase. Methods In an attempt to enhance Bxb1 serine integrase-mediated integration efficiency, we fused various nuclear localization signals (NLS) to the N- and C-termini of the integrase. Concurrently, we co-expressed multiple proteins associated with nuclear transport to assess their impact on the stable integration efficiency of green fluorescent protein (GFP)-encoding DNA and an antibody display cassette into the genome of Chinese hamster ovary (CHO) cells containing a landing pad for Bxb1 integrase-mediated integration. Results The nucleoplasmin NLS from Xenopus laevis, when fused to the C-terminus of Bxb1 integrase, demonstrated the highest enhancement in stable integration efficiency among the tested NLS fusions, exhibiting over a 6-fold improvement compared to Bxb1 integrase lacking an NLS fusion. Subsequent additions of extra NLS fusions to the Bxb1 integrase revealed an additional 131% enhancement in stable integration efficiency with the inclusion of two copies of C-terminal nucleoplasmin NLS fusions. Further improvement was achieved by co-expressing the Ran GTPase-activating protein (RanGAP). Finally, to validate the applicability of these findings to more complex proteins, the DNA encoding the membrane-bound clinical antibody abrilumab was stably integrated into the genome of CHO cells using Bxb1 integrase with two copies of C-terminal nucleoplasmin NLS fusions and co-expression of RanGAP. This approach demonstrated over 14-fold increase in integration efficiency compared to Bxb1 integrase lacking an NLS fusion. Conclusions This study demonstrates that optimizing the NLS sequence fusion for Bxb1 integrase significantly enhances the stable genomic integration efficiency. These findings provide a practical approach for constructing larger libraries in mammalian cells through the stable integration of genes into a genomic landing pad.

Abstract Geological evidence indicates that a supernova within 100 parsecs of Earth occurs around once per million years. Such nearby supernovas can produce an intense gamma-ray burst and a 100-fold increase of cosmic rays, lasting several centuries. We find that the effect of a short burst of gamma rays is small since they are strongly attenuated before reaching the lower stratosphere. Intense cosmic radiation affects stratospheric ozone but, due to compensating effects in catalytic chemical cycles, ozone depletion is moderate and comparable to that from current anthropogenic emissions. This also holds for the low-oxygen atmosphere during early evolution of terrestrial life. We estimate the increase in aerosol and clouds from a 100-fold increase of cosmic rays exerts a radiative forcing comparable in magnitude but opposite in sign to current anthropogenic climate forcing. We conclude that Earth’s atmosphere is effective at shielding the biosphere from nearby supernovae.

As an increasing share of the human population is being clustered in cities, urban areas have swiftly become the epicentres of anthropogenic carbon (C) emissions. Understanding different parts of the biogenic C cycle in urban ecosystems is needed in order to assess the potential to enhance their C stocks as a cost-efficient means to balance the C emissions and mitigate climate change. Here, we conducted a field measurement campaign over three consecutive growing seasons to examine soil respiration carbon dioxide (CO2) fluxes and soil organic carbon (SOC) stocks at four measurement sites in Helsinki, representing different types of tree-covered urban green space commonly found in northern European cities. We expected to find variation in the main drivers of soil respiration – soil temperature, soil moisture, and SOC – as a result of the heterogeneity of urban landscape and that this variation would be reflected in the measured soil respiration rates. In the end, we could see fairly constant statistically significant differences between the sites in terms of soil temperature but only sporadic and seemingly momentary differences in soil moisture and soil respiration. There were also statistically significant differences in SOC stocks: the highest SOC stock was found in inactively managed deciduous urban forest and the lowest under managed streetside lawn with common linden trees. We studied the impacts of the urban heat island (UHI) effect and irrigation on heterotrophic soil respiration with process-based model simulations and found that the variation created by the UHI is relatively minor compared to the increase associated with active irrigation, especially during dry summers. We conclude that, within our study area, the observed variation in soil temperature alone was not enough to cause variation in soil respiration rates between the studied green space types, perhaps because the soil moisture conditions were uniform. Thus, irrigation could potentially be a key factor in altering the soil respiration dynamics in urban green space both within the urban area and in comparison to non-urban ecosystems.

Atmospheric aerosol particles have a considerable influence on climate via both aerosol–radiation and aerosol–cloud interactions. A major fraction of global aerosol particles, in terms of their number concentration, is due to atmospheric new particle formation (NPF) that involves both neutral and charged clusters and particles. NPF is the major source of atmospheric intermediate ions, i.e., charged particles with mobility diameters between approx. 2 and 7 nm. We investigate ion concentrations between 1.7 and 3.1 nm at the SMEAR II (Station for Measuring Forest Ecosystem–Atmosphere Relations II) measurement station in Hyytiälä, Finland. Both negative and positive ion number size distributions measured by a Neutral cluster and Air Ion Spectrometer (NAIS) are used. Our aim is to find the best diameter size range of ions for identifying and evaluating the intensity of local intermediate ion formation (LIIF). Intermediate ion formation (IIF) refers to the formation of intermediate ions through NPF, while local means that the growth of such ions from smaller clusters has occurred in close proximity (e.g., within 500 m to 1 km) to the measurement site, i.e., locally. We find that the ions in the mobility diameter size range of 2.0–2.3 nm are the best suited for detection of LIIF. The ion concentrations in this size range indicate the elevated rates of IIF, and the potential distances the growing ions have traveled are smaller than those for larger ions. In addition, in Hyytiälä, the negative ion concentrations are more sensitive to IIF than the positive ion concentrations due to the higher difference in concentrations between periods of IIF and the background. Therefore, we recommend the concentrations of ions with diameters 2.0–2.3 nm as the best choice for identifying and evaluating the intensity of LIIF.

We integrated Enviro-HIRLAM (Environment-High Resolution Limited Area Model) meteorological output into FLEXPART (FLEXible PARTicle dispersion model). A FLEXPART simulation requires meteorological input from a numerical weather prediction (NWP) model. The publicly available version of FLEXPART can utilize either ECMWF (European Centre for Medium-range Weather Forecasts) Integrated Forecast System (IFS) forecast or reanalysis NWP data, or NCEP (U.S. National Center for Environmental Prediction) Global Forecast System (GFS) forecast or reanalysis NWP data. The primary benefits of using Enviro-HIRLAM are that it runs at a higher resolution and accounts for aerosol effects in meteorological fields. We compared backward trajectories generated with FLEXPART using Enviro-HIRLAM (both with and without aerosol effects) to trajectories generated using NCEP GFS and ECMWF IFS meteorological inputs, for a case study of a heavy haze event which occurred in Beijing, China in November 2018. We found that results from FLEXPART were considerably different when using different meteorological inputs. When aerosol effects were included in the NWP, there was a small but noticeable difference in calculated trajectories. Moreover, when looking at potential emission sensitivity instead of simply expressing trajectories as lines, additional information, which may have been missed when looking only at trajectories as lines, can be inferred.

To manage Earth in the Anthropocene, new tools, new institutions, and new forms of international cooperation will be required. Earth Virtualization Engines is proposed as an international federation of centers of excellence to empower all people to respond to the immense and urgent challenges posed by climate change.

The Pan-Eurasian Experiment Modelling Platform (PEEX-MP) is one of the key blocks of the PEEX Research Programme. The PEEX MP has more than 30 models and is directed towards seamless environmental prediction. The main focus area is the Arctic-boreal regions and China. The models used in PEEX-MP cover several main components of the Earth’s system, such as the atmosphere, hydrosphere, pedosphere and biosphere, and resolve the physical-chemical-biological processes at different spatial and temporal scales and resolutions. This paper introduces and discusses PEEX MP multi-scale modelling concept for the Earth system, online integrated, forward/inverse, and socioeconomical modelling, and other approaches with a particular focus on applications in the PEEX geographical domain. The employed high-performance computing facilities, capabilities, and PEEX dataflow for modelling results are described. Several virtual research platforms (PEEX-View, Virtual Research Environment, Web-based Atlas) for handling PEEX modelling and observational results are introduced. The overall approach allows us to understand better physical-chemical-biological processes, Earth’s system interactions and feedbacks and to provide valuable information for assessment studies on evaluating risks, impact, consequences, etc. for population, environment and climate in the PEEX domain. This work was also one of the last projects of Prof. Sergej Zilitinkevich, who passed away on 15 February 2021. Since the finalization took time, the paper was actually submitted in 2023 and we could not argue that the final paper text was agreed with him.

Abstract The growth of newly formed particles through new particle formation (NPF) contributes a significant fraction to the cloud condensation nuclei, yet the driving mechanisms remain unclear, especially for polluted environments. To investigate the potential species contributing for nanoparticle growth in environments with significant anthropogenic influences, we measured the hygroscopicity of newly formed particles at 20–40 nm at a rural observational site in the North China Plain during winter 2018. Our results demonstrate that these particles were not very hygroscopic, with the mean hygroscopicity parameter κ of 0.13 ± 0.09. Clear differences in the inferred κ of the growing material responsible for the growth were observed among different events, indicating that even at the same region, the compounds driving particle growth may not be identical. This may be synergistically influenced by the NPF precursors, oxidants and meteorological conditions, suggesting complex mechanisms might co‐exist behind nanoparticle growth in polluted environments.