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Recent years have shown that secondary ice production (SIP) is ubiquitous, affecting all clouds from polar to tropical regions. SIP is not described well in models and may explain biases in warm mixed-phase cloud ice content and structure. Through modeling constrained by in-situ observations and its synergy with radar we show that SIP in orographic clouds exert a profound impact on the vertical distribution of hydrometeors and precipitation, especially in seeder-feeder cloud configurations. The mesoscale model simulations coupled with a radar simulator strongly support that enhanced aggregation and SIP through ice-ice collisions contribute to observed spectral bimodalities, skewing the Doppler spectra toward the slower-falling side at temperatures within the dendritic growth layer, ranging from −20 °C to −10 °C. This unique signature provides an opportunity to infer long-term SIP occurrences from the global cloud radar data archive, particularly for this underexplored temperature regime. [ABSTRACT FROM AUTHOR]

This work presents the first comprehensive assessment of PM pollution sources in Dushanbe, Tajikistan. A total of 138 PM2.5 samples were collected during 2015–2016 and 2018–2019 and were analyzed through gravimetric, ED-XRF, and multi-wavelength absorption techniques. The results show that PM2.5 concentrations were substantially higher than the European annual limit value and WHO Air Quality Guidelines annual average value, with an average of 90.9 ± 68.5 μg m−3. The PMF application identified eight sources of pollution that influenced PM2.5 concentration levels in the area. Coal burning (21.3%) and biomass burning (22.3%) were the dominant sources during the winter, while vehicular traffic (7.7%) contributed more during the warm season. Power plant emissions (17.5%) showed enhanced contributions during the warm months, likely due to high energy demand. Cement industry emissions (6.9%) exhibited significant contribution during the cold period of 2018–2019, while soil dust (11.3%) and secondary sulphates (11.5%) displayed increased contribution during the warm and cold months, respectively. Finally, waste burning (1.5%) displayed the lowest contribution, with no significant temporal variation. Our results highlight the significant impact of anthropogenic activities, and especially the use of coal burning for energy production (both in power plants and for residential heating), and the significant contribution of biomass burning during both warm and cold seasons. [ABSTRACT FROM AUTHOR]

Wildfires are a significant source of organic aerosol during summer, with major impacts on air quality and climate. However, studies in Europe suggest a surprisingly low (less than 10%) contribution of biomass burning organic aerosol to average summertime fine particulate matter levels. In this study we combine field measurements and atmospheric chemical transport modeling, to demonstrate that the contribution of wildfires to fine particle levels in Europe during summer is seriously underestimated. Our work suggests that the corresponding contribution has been underestimated by a factor of 4–7 and that wildfires were responsible for approximately half of the total OA in Europe during July 2022. This discrepancy with previous work is due to the rapid physicochemical transformation of these emissions to secondary oxidized organic aerosol with an accompanying loss of its organic chemical fingerprints. These atmospheric reactions lead to a regionally distributed background organic aerosol that is responsible for a significant fraction of the health-related impacts caused by fine particles in Europe and probably in other continents. These adverse health effects can occur hundreds or even thousands of kilometers away from the fires. We estimate that wildfire emissions are responsible for 15–22% of the deaths in Europe due to exposure to fine particulate matter during summer. [ABSTRACT FROM AUTHOR]

Air quality in urban areas and megacities is dependent on emissions, physicochemical process and atmospheric conditions in a complex manner. The impact on air quality metrics of the COVID-19 lockdown measures was evaluated during two periods in Athens, Greece. The first period involved stoppage of educational and recreational activities and the second severe restrictions to all but necessary transport and workplace activities. Fresh traffic emissions and their aerosol products in terms of ultrafine nuclei particles and nitrates showed the most significant reduction especially during the 2nd period (40–50%). Carbonaceous aerosol both from fossil fuel emissions and biomass burning, as well as aging ultrafine and accumulation mode particles showed an increase of 10–20% of average before showing a decline (5 to 30%). It is found that removal of small nuclei and Aitken modes increased growth rates and migration of condensable species to larger particles maintaining aerosol volume. [ABSTRACT FROM AUTHOR]

Biomass burning caused by anthropogenic activity such as agriculture-burning periods (common practice during harvesting, post-harvesting, or preplanting) or naturally occurring forest fires, and domestic biofuel combustion is a frequent phenomenon causing global concern. Agricultural burning, although restricted in some countries, significantly contributes to regional air-quality deterioration and national emissions. This work focuses on atmospheric measurements at the suburbs of Athens, on August 2010, during extensive forest fires in the European Russian central plains. The effect of these fires on the measured concentrations of specific radioactive isotopes and biomass-burning tracers was studied, for long-range transport of aerosols from Russian plains. Mean total beta radioactivity was found more than 2.5 times higher during the incident compared to background values. High values were also reported for the isotope 40K, and its fluctuations were following the course of the event. 7Be showed no significant difference between the two periods, which is expected due to its origin. During the event 234Th (238U), activity concentrations were also detected. Their fluctuations showed no significant correlation with the course of the event. The average values during the period before and right after the incident is for organic carbon 2.74 μg/m3, elemental carbon 1.53 μg/m3, and for carbonate carbon 0.16 μg/m3. During the incident, the highest values were observed on August 18, with concentrations for organic carbon 5.49 μg/m3, elemental carbon 0.64 μg/m3, and carbonate carbon 0.32 μg/m3. This fact may be considered as an indicator of biomass-burning incident during the period 12–19 August 2010. [ABSTRACT FROM AUTHOR]

Thessaloniki, the second largest city in Greece, has seen a sudden attempt to establish LGBT politics during the last 5 years, due to movement mobilization and favourable local and European opportunity structures. The article suggests a multiscalar analysis of Thessaloniki Prides, which takes into account politics articulated by a series of actors located in distinct scales. These actors include institutional and religious authorities, as well as the local LGBT movement. The analysis demonstrates that Thessaloniki Prides are shaped by conflicting discursive blocks articulated through the national, urban/local, and transnational scale. Prides, as the most visible outcome of the local LGBT movement, become a collective action, which is shaped and continuously challenged by its embeddedness in these scales. This analysis brings new insights into the geo-temporal politics of LGBT politics, reminding that European periphery's sexual politics are located in a nexus of progressive cosmopolitanism and nationalist anti-modernity. In fact, the Thessaloniki case demonstrates that being part of the Western periphery places sexual politics between a globalist EU-ized discourse of modernity on the one hand and anti-secular views on heteronormative traditions on the other. Such a space is the setting where grassroots LGBTQ movements perform their politics. [ABSTRACT FROM AUTHOR]

Real-time PM mass concentrations were monitored inside the trains and in several platforms of red and blue lines in Athens metro system during two measurement campaigns. Furthermore, measurements of PM, PM, and PM concentrations were conducted on a fixed site on a subway platform of blue line (Nomismatokopio) and the majority of particles were in the fine mode. PM concentrations were measured inside the metro trains along the entire route of the two metro lines during commuting hours, and the average PM concentration was 132.2 ± 34.0 μg/m in the red line and 138.0 ± 35.6 μg/m in the blue line. Measurements were also conducted in eight platforms and higher concentrations were observed in stations located in the center of Athens, under heavily trafficked streets. An exposure and dose assessment model, ExDoM2, was implemented in order to calculate the deposition, dose, and retention of aerosol particles in the respiratory tract (RT), the gastrointestinal (GI) tract, and their absorption to blood. The model was applied to study the human dose of three different subjects, a person with sedentary employment commuting by metro 1 h per day, a metro worker with sedentary activity, and a metro worker with light exercise activity. The dose varies in the different regions of the RT with the highest dose in the extrathoracic region. The dose in the RT after commuting by metro for 1 h was 125.4 μg that corresponds to 36.3% of the total personal daily dose (worst-case scenario, no indoor sources). [ABSTRACT FROM AUTHOR]

The aim of this work is to study the atmospheric concentrations of selected major and trace elements and ions found in PM, at a suburban site in Athens, Greece, and discuss on the impact of the different sources. Special focus is given to the influence of Saharan dust episodes. The seasonal variability in the metal and ion concentrations is also examined. The results show that PM mass concentrations are significantly influenced by Saharan dust events; it is observed that when the PM concentration is higher than 25 μg/m, five out of six times, the air mass crossed North Africa at an altitude within the boundary layer. Fe is found to be the element with the more significant seasonal variability, displaying much higher concentrations during cold period. The frequent Saharan dust intrusions in the cold period of this dataset may explain this result. Mineral dust and secondary aerosol are the main PM components (29 and 34%, respectively). During Saharan dust events, the concentration of mineral dust is increased by 35% compared to the days without dust intrusions, while an increase of 68% of the sea salt is also observed. During event days, PM concentrations are also increased by 14%. Anthropogenic components do not decrease during those days, while sulfate displays even a slight increase, suggesting enrichment of mineral dust with secondary sulfates. The results indicate that African dust intrusions add a rather significant PM pollution load even in the PM fraction, with implication to population exposure and human health. [ABSTRACT FROM AUTHOR]

Measurement of air exchange rate provides critical information in energy and indoor-air quality studies. Continuous measurement of ventilation rates is a rather costly exercise and requires specific instrumentation. In this work, an alternative methodology is proposed and tested, where the air exchange rate is calculated by utilizing indoor and outdoor routine measurements of a common pollutant such as SO 2, whereas the uncertainties induced in the calculations are analytically determined. The application of this methodology is demonstrated, for three residential microenvironments in Athens, Greece, and the results are also compared against ventilation rates calculated from differential pressure measurements. The calculated time resolved ventilation rates were applied to the mass balance equation to estimate the particle loss rate which was found to agree with literature values at an average of 0.50 h −1. The proposed method was further evaluated by applying a mass balance numerical model for the calculation of the indoor aerosol number concentrations, using the previously calculated ventilation rate, the outdoor measured number concentrations and the particle loss rates as input values. The model results for the indoors’ concentrations were found to be compared well with the experimentally measured values. [ABSTRACT FROM AUTHOR]

Correction to: I Scientific Reports i https://doi.org/10.1038/s41598-021-93650-6, published online 14 July 2021 The original version of this Article contained an error in Affiliation 1, which was incorrectly given as 'Environmental Research Laboratory, INRASTES, NCSR Demokritos, 15310 Ag. Paraskevi, Athens, Greece'. The correct affiliation is listed below: Environmental Radioactivity Laboratory, INRASTES, NCSR Demokritos, 15310 Ag. Paraskevi, Athens, Greece The original Article has been corrected. [Extracted from the article]

The article announces that the article "Influence of local and regional sources on the observed variability in the concentration levels of fine and coarse atmospheric aerosol water-soluble species in Athens," by Panagiotis Razos and Konstantinos Eleftheriadis has been retracted from publication.