A twenty year record of greenhouse gases in the Eastern Mediterranean atmosphere.

Twenty years of CO2, CH4 and CO greenhouse gas atmospheric concentration measurements at Finokalia station on Crete in the Eastern Mediterranean region are presented. This dataset is the longest in the Eastern Mediterranean, based on bi-weekly grab sampling since 2002 and continuous observations since June 2014. CO2 concentrations increase by 2.4 ppm·y-1 since 2002, in agreement with the general north hemisphere trend as derived by worldwide NOAA observations. CH4 showed a mean increasing trend of 7.5 ppb·y-1 since 2002, a rate that has accelerated since 2018 (12.4 ppb·y-1). In contrast, CO has decreased by 1.6 ppb·y-1 since 2002, which resulted from a strong decrease until 2017 (2.5 ppb·y-1), followed by a small increase in the last 3 years (0.2 ppb·y-1). Both CO2 and CH4 present maxima during winter and minima during summer, in general agreement with the observations at the ICOS stations in Europe. CO also presents the highest values in winter and the lowest values in summer during June, while a secondary maximum is seen in August, which can be attributed to open fires that often occur in the area during this period. The mean summertime diurnal cycles of CH4 and CO agree with a 24-h mean OH radical concentration of the order of 0.3-1 × 107 molecules·cm-3 over the region, in general agreement with the only existing in-situ observations at Finokalia for 2001.

Improved indoor air quality during desert dust storms: The impact of the MEDEA exposure-reduction strategies.

Desert dust storms (DDS) are natural events that impact not only populations close to the emission sources but also populations many kilometers away. Countries located across the main dust sources, including countries in the Eastern Mediterranean, are highly affected by DDS. In addition, climate change is expanding arid areas exacerbating DDS events. Currently, there are no intervention measures with proven, quantified exposure reduction to desert dust particles. As part of the wider "MEDEA" project, co-funded by LIFE 2016 Programme, we examined the effectiveness of an indoor exposure-reduction intervention (i.e., decrease home ventilation during DDS events and continuous use of air purifier during DDS and non-DDS days) across homes and/or classrooms of schoolchildren with asthma and adults with atrial fibrillation in Cyprus and Crete-Greece. Participants were randomized to a control or intervention groups, including an indoor intervention group with exposure reduction measures and the use of air purifiers. Particle sampling, PM10 and PM2.5, was conducted in participants' homes and/or classrooms, between 2019 and 2022, during DDS-free weeks and during DDS days for as long as the event lasted. In indoor and outdoor PM10 and PM2.5 samples, mass and content in main and trace elements was determined. Indoor PM2.5 and PM10 mass concentrations, adjusting for premise type and dust conditions, were significantly lower in the indoor intervention group compared to the control group (PM2.5-intervention/PM2.5-control = 0.57, 95% CI: 0.47, 0.70; PM10-intervention/PM10-control = 0.59, 95% CI: 0.49, 0.71). In addition, the PM2.5 and PM10 particles of outdoor origin were significantly lower in the intervention vs. the control group (PM2.5 infiltration intervention-to-control ratio: 0.49, 95% CI: 0.42, 0.58; PM10 infiltration intervention-to-control ratio: 0.68, 95% CI: 0.52, 0.89). Our findings suggest that the use of air purifiers alongside decreased ventilation measures is an effective protective measure that reduces significantly indoor exposure to particles during DDS and non-DDS in high-risk population groups.

Water soluble reactive phosphate (SRP) in atmospheric particles over East Mediterranean: The importance of dust and biomass burning events.

The importance of dust and biomass burning episodes on the atmospheric concentration of water-soluble reactive phosphate (SRP) was determined in the eastern Mediterranean. SRP was measured with a new rapid real-time automated analytical system with a time resolution of a few minutes per sample and with an extremely low detection limit. The average atmospheric concentration of SRP during the sampling campaign was estimated at 0.35 ± 0.25 (median 0.30) nmol P m-3. The maximum concentration of SRP (3.08 nmol P m-3) was recorded during an intense dust episode, and was almost ten times higher than the campaign average, confirming that Saharan dust was an important primary source of bioavailable P to the eastern Mediterranean, especially during the spring period when 60% of the events occurred. Predicted increases in the frequency and intensity of dust storms in the area will enhance the role of the atmosphere as a source of bioavailable P for the Mediterranean marine ecosystem. During the warm period, when Northerly winds prevailed, biomass burning processes contributed significantly to soluble phosphorus delivered from atmospheric sources to the eastern Mediterranean. These inputs during warm periods are especially important for the Eastern Mediterranean, where biological productivity is strongly limited by nutrient availability.

Extreme desert dust storms and COPD morbidity on the island of Crete.

Introduction and objectives: Short-term extreme increases in desert-derived particulate-matter with aerodynamic diameter below 10 µm (PM10) may affect emergency department (ED) visits due to COPD exacerbations. Research question: Our aim was to identify the effect of extreme increases in desert-derived PM10 on ED visits for dyspnea and COPD exacerbations and on the related hospital admissions. Methods: We performed a retrospective analysis of dyspnea-related ED visits and hospital admissions in Heraklion, Crete, during four consecutive storms of desert-derived PM10 that happened during March 2018. We collected data from over 17,000 ED visits and recorded patients with atopic symptoms, COPD exacerbations, and dyspnea, as well as admissions to the departments of pulmonary medicine, internal medicine, and cardiology. PM10 data were collected from a monitoring station in the same geographic area. Results: Four desert dust storms were recorded during the study period with 238, 203, 1138, and 310 µg/m3 average-daily PM10 and 652, 308, 4262, and 778 µg/m3 hourly mean day-peak PM10, respectively. There was no clinically important increase in total ED visits, total admissions or admissions to the departments of cardiology, pulmonary medicine, or internal medicine, during PM10 peaks. However, during the desert dust storm with daily-average PM10 above 500 µg/m3, there was a striking increase in dyspnea-related ED visits (including COPD exacerbations, 3.6-fold increase), while there was no clinically important increase in non-asthma allergy-related ED visits. Conclusion: Extreme desert dust storm episodes may cause meaningful increases in ED visits for dyspnea and COPD exacerbations/admissions.

Polybrominated diphenyl ethers (PBDEs) in background air around the Aegean: implications for phase partitioning and size distribution.

The occurrence and atmospheric behavior of tri- to deca-polybrominated diphenyl ethers (PBDEs) were investigated during a 2-week campaign concurrently conducted in July 2012 at four background sites around the Aegean Sea. The study focused on the gas/particle (G/P) partitioning at three sites (Ag. Paraskevi/central Greece/suburban, Finokalia/southern Greece/remote coastal, and Urla/Turkey/rural coastal) and on the size distribution at two sites (Neochorouda/northern Greece/rural inland and Finokalia/southern Greece/remote coastal). The lowest mean total (G + P) concentrations of ∑7PBDE (BDE-28, BDE-47, BDE-66, BDE-99, BDE-100, BDE-153, BDE-154) and BDE-209 (0.81 and 0.95 pg m-3, respectively) were found at the remote site Finokalia. Partitioning coefficients, K P, were calculated, and their linear relationships with ambient temperature and the physicochemical properties of the analyzed PBDE congeners, i.e., the subcooled liquid pressure (P L°) and the octanol-air partition coefficient (K OA), were investigated. The equilibrium adsorption (P L°-based) and absorption (K OA-based) models, as well as a steady-state absorption model including an equilibrium and a non-equilibrium term, both being functions of log K OA, were used to predict the fraction Φ of PBDEs associated with the particle phase. The steady-state model proved to be superior to predict G/P partitioning of BDE-209. The distribution of particle-bound PBDEs across size fractions < 0.95, 0.95-1.5, 1.5-3.0, 3.0-7.2, and > 7.2 µm indicated a positive correlation between the mass median aerodynamic diameter and log P L° for the less brominated congeners, whereas a negative correlation was observed for the high brominated congeners. The potential source regions of PBDEs were acknowledged as a combination of long-range transport with short-distance sources.