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Organic carbon (OC), elemental carbon (EC), water-soluble organic carbon (WSOC) and main ions were measured in a total of 1510 PM2.5 daily aerosol samples collected from May 2008 to April 2013 in Athens, Greece. OC and EC concentrations were 2.1 ± 1.3 μgm-3 and 0.54 ± 0.39 μgm-3 , accounting for 11 ± 3 % and 3 ± 1 % of PM2.5 mass, respectively, with an average OC / EC ratio of 4.7 ± 3.1. Significant correlation was found between OC and EC during the whole period, indicating emissions by common primary sources on a regional scale. WSOC concentration ranged from 0.03 to 10.6pgm-3 , with an average of 1.5 ± 0.9 μgm-3 . By considering the Finokalia (Crete) station as a reference, it was estimated that, during the warm season in Athens, 67 ± 7% of emitted OC and 53 ± 12% of emitted EC is regional, while, during cold months, the regional contribution of OC is only 33 ± 7 % and of EC 29 ± 8 %. Furthermore, secondary organic carbon (SOC) was calculated for the warm period of the year (April to October). The estimated SOC constituted about 75 ± 6 % of PM2.5 organic carbon in Athens, highlighting significant aging processes on a regional scale. In the period 2011-2013 and during wintertime, an increase in OC and EC levels was observed, attributed to an increase in wood burning for domestic heating due to the economic crisis. [ABSTRACT FROM AUTHOR]

Many studies have drawn attention to the associations of oxygenated polycyclic aromatic hydrocarbons (OPAHs) with harmful health effects, advocating for their systematic monitoring alongside simple PAHs to better understand the aerosol carcinogenic potential in urban areas. To address this need, this study conducted an extensive PM 2.5 sampling campaign in Athens, Greece, at the Thissio Supersite of the National Observatory of Athens, from December 2018 to July 2021, aiming to characterize the levels and variability of polycyclic aromatic compounds (PACs), perform source apportionment, and assess health risk. Cumulative OPAH concentrations (Σ-OPAHs) were in the same range as Σ-PAHs (annual average 4.2 and 5.6 ng m -3 , respectively). They exhibited a common seasonal profile with enhanced levels during the heating seasons, primarily attributed to residential wood burning (RWB). The episodic impact of biomass burning was also observed during a peri-urban wildfire event in May 2021, when PAH and OPAH concentrations increased by a factor of three compared to the monthly average. The study period also included the winter 2020-2021 COVID-19 lockdown, during which PAH and OPAH levels decreased by >50 % compared to past winters. Positive matrix factorization (PMF) source apportionment, based on a carbonaceous aerosol speciation dataset, identified PAC sources related to RWB, local traffic (gasoline vehicles) and urban traffic (including diesel emissions), as well as an impact of regional organic aerosol. Despite its seasonal character, RWB accounted for nearly half of Σ-PAH and over two-thirds of Σ-OPAH concentrations. Using the estimated source profiles and contributions, the source-specific carcinogenic potency of the studied PACs was calculated, revealing that almost 50 % was related to RWB. These findings underscore the urgent need to regulate domestic biomass burning at a European level, which can provide concrete benefits for improving urban air quality, towards the new stricter EU standards, and reducing long-term health effects., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024. Published by Elsevier B.V.)

To study the spatiotemporal variability of particle-bound polycyclic aromatic hydrocarbons (PAHs) and assess their carcinogenic potential in six contrasting urban environments in Greece, a total of 305 filter samples were collected and analyzed. Sampling sites included a variety of urban background, traffic (Athens, Ioannina and Heraklion), rural (Xanthi) and near-port locations (Piraeus and Volos). When considering the sum of 16 U.S. EPA priority PAHs, as well as that of the six EU-proposed members, average concentrations observed across locations during summer varied moderately (0.4-2.2 ng m -3 ) and independently of the population of each site, with the highest values observed in the areas of Piraeus and Volos that are affected by port and industrial activities. Winter levels were significantly higher and more spatially variable compared to summer, with the seasonal enhancement ranging from 7 times in Piraeus to 98 times in Ioannina, indicating the large impact of PAH emissions from residential wood burning. Regarding benzo(a)pyrene (BaP), an IARC Group 1 carcinogen and the only EU-regulated PAH, the winter/summer ratios were 24-33 in Athens, Volos, Heraklion and Xanthi; 60 in Piraeus; and 480 in Ioannina, which is afflicted by severe wood-burning pollution events. An excellent correlation was observed between organic carbon (OC) and benzo(a)pyrene (BaP) during the cold period at all urban sites (r 2 > 0.8) with stable BaP/OC slopes (0.09-0.14 × 10 -3 ), highlighting the potential use of OC as a proxy for the estimation of BaP in winter conditions. The identified spatiotemporal contrasts, which were explored for the first time for PAHs at such a scale in the Eastern Mediterranean, provide important insights into sources and controlling atmospheric conditions and reveal large deviations in exposure risks among cities that raise the issue of environmental injustice on a national level., Competing Interests: The authors declare no conflicts of interest.

Wildfires occurring near urban areas are known to have exceedingly detrimental impacts on the environment, air quality, economy and human health. In this framework, this study examines the effects of peri-urban forest fires on atmospheric chemical composition, and aerosol physical-optical properties in Athens, Greece, during August 2021. Satellite imagery and air mass trajectories showed advection of intense smoke plumes over Athens from three forest fires persisting for 10 days in the greater Athens area and in Central Greece (Euboea). During August 1-20, 2021, daily PM 2.5 concentrations ranged from 8.9 to 78.7 μg m -3 , and were associated with high OC levels (2.3-27.8 μg m -3 ), while BC and BC bb concentrations on smoke-impacted days were 2.6 μg m -3 and 1.0 μg m -3 , respectively (2-3 times higher than August mean levels). During the peak of biomass burning (BB) smoke transport over Athens, daily-average scattering and absorption coefficients at short wavelengths maximized at 313 Mm -1 and 171 Mm -1 , respectively. There was also a large impact of ambient BrC (brown carbon) absorption (60 Mm -1 ), while the OC/EC ratio exhibited characteristically low values (3-4), linked to flaming combustion (modified combustion efficiency of 0.97-0.99). The absorption Ångström exponent (1.38) and single scattering albedo (0.74) indicated highly absorbing BB aerosol, deviating from the normal summer patterns. BB-tracers like nssK + displayed strong correlations with OC, EC and BC concentrations, as well as with scattering and absorption coefficients. However, forest fires drastically modified the levels of additional chemical species, with enhancements observed for Ca 2+ , NO 3 - , Cl - , and for organic aerosol (OA) components such as BBOA and less-oxidized oxygenated OA (LO-OOA). Since under climate change conditions, the Mediterranean is anticipated to experience a dramatic rise in the frequency and intensity of wildfires, the results highlight the necessity for prevention and mitigation policies to safeguard urban air quality., (Copyright © 2023. Published by Elsevier B.V.)

Background: The strategy of cardiac implantable electronic device (CIED) implantations performed as day-case admissions has gained a wider acceptance overtime; however, data on safety are still limited. This study aims to investigate the safety of a same-day discharge protocol introduced in our hospital for the postprocedural management of patients undergoing CIED implantation., Methods: Α prospective, non-interventional, non-randomised study performed in a single high-volume implanting centre for a 16-month period (March 2020 to June 2021). At total of 821 of 965 (85.1%) patients scheduled for elective CIED implantation were considered to be eligible for inclusion in the Short-stay Device Management Protocol. These patients were compared with a historical group of 932 patients, meeting the same inclusion criteria., Results: Procedure was successful in 812 patients (98.9%), committed to same-day discharge versus 921 of 932 patients (98.8%) admitted for overnight stay (p = 0.87). Overall, 90-day complication rate was comparable in both groups (4.14% vs 4.07%, p = 0.95), as was major (1.46% vs. 1.82%, p = 0.55) and minor (2.67% vs. 2.25%, p = 0.64) complication rates. The composite early post-procedural complication rates and late post-procedural complication rates were comparable among groups (0.97 vs 1.18%, p = 0.70 and 0.73% vs 0.64%, p = 0.83, respectively). Six hundred sixty-seven patients (84%) preferred the same-day discharge strategy. Finally, a reduction of 792 bed-days was recorded, resulting in possible financial Health System benefits., Conclusions: Same-day discharge is feasible and safe in the majority of patients referred for CIED implantation. Additionally, same-day discharge is preferred by patients and may reduce procedure-related costs due to significant bed-day reductions., (© 2022. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

This work evaluates the aerosol oxidative potential (OP) and its changes from modified air pollution emissions during the COVID-19 lockdown period in 2020, with the intent of elucidating the contribution of aerosol sources and related components to aerosol OP. For this, daily particulate matter (PM) samples at an urban background site were collected and analyzed with a chemical (acellular) assay based on Dithiothreitol (DTT) during the COVID-19 restriction period in Athens (Greece). The obtained time-series of OP, PM 2.5 , organic matter (OM) and SO 4 2- of the pre-, post- and lockdown periods were also compared to the data of the same time periods during the years 2017-2019. Even though all traffic-related emissions have been significantly reduced during the lockdown period (by 30%), there is no reduction in water-soluble OP, organics and sulfate concentrations of aerosol during 2020. The results reveal that the decrease in traffic was not sufficient to drive any measurable change on OP, suggesting that other sources-such as biomass burning and secondary aerosol from long-range transport, which remained unchanged during the COVID lockdown-are the main contributors to OP in Athens, Greece.

His bundle pacing (HBP) is proven to be a safe and effective alternative pacing modality that, in addition, avoids pacemaker-induced cardiomyopathy (PICM) by achieving a "physiological" ventricular stimulation, via the native conduction system. Indications include various causes of bradycardia requiring anti-bradycardic pacing, inadequately controlled atrial fibrillation requiring AV node ablation and established PICM. In addition, HBP may also be used as an alternative therapy for patients with heart failure (HF) and an indication for cardiac resynchronization therapy (CRT). Available data show several advantages of HBP with regard to preservation or restoration of intra- and inter-ventricular synchronization; improvement in left ventricular ejection fraction, functional status and quality of life; decrease in atrial fibrillation incidence and improvement in HF hospitalization rates, compared with conventional pacing. Nevertheless, superiority in terms of mortality rates has not been consistently demonstrated, and the long-term efficacy and safety of HBP remain to be proven. In the present manuscript, we review the status of HBP and present our current experience with this novel pacing modality., (Copyright © 2021 Hellenic Society of Cardiology. Published by Elsevier B.V. All rights reserved.)