Inter-annual trends of ultrafine particles in urban Europe

Ultrafine particles (UFP, those with diameters ≤ 100 nm), have been reported to potentially penetrate deeply into the respiratory system, translocate through the alveoli, and affect various organs, potentially correlating with increased mortality. The aim of this study is to assess long-term trends (5-11 years) in mostly urban UFP concentrations based on measurements of particle number size distributions (PNSD). Additionally, concentrations of other pollutants and meteorological variables were evaluated to support the interpretations. PNSD datasets from 12 urban background (UB), 5 traffic (TR), 3 suburban background (SUB) and 1 regional background (RB) sites in 15 European cities and 1 in the USA were evaluated. The non-parametric Theil-Sen's method was used to detect monotonic trends. Meta-analyses were carried out to assess the overall trends and those for different environments. The results showed significant decreases in NO, NO2, BC, CO, and particle concentrations in the Aitken (25-100 nm) and the Accumulation (100-800 nm) modes, suggesting a positive impact of the implementation of EURO 5/V and 6/VI vehicle standards on European air quality. The growing use of Diesel Particle Filters (DPFs) might also have clearly reduced exhaust emissions of BC, PM, and the Aitken and Accumulation mode particles. However, as reported by prior studies, there remains an issue of poor control of Nucleation mode particles (smaller than 25 nm), which are not fully reduced with current DPFs, without emission controls for semi-volatile organic compounds, and might have different origins than road traffic. Thus, contrasting trends for Nucleation mode particles were obtained across the cities studied. This mode also affected the UFP and total PNC trends because of the high proportion of Nucleation mode particles in both concentration ranges. It was also found that the urban temperature increasing trends might have also influenced those of PNC, Nucleation and Aitken modes.

Soil Moisture Conservation through Crop Diversification and Related Ecosystem Services in a Blown-Sand Area with High Drought Hazard

Soil moisture reserves are a key factor in maintaining soil fertility and all other related ecosystem services (including carbon sequestration, soil biodiversity, and soil erosion control). In semiarid blown-sand areas under aridification, water preservation is a particularly crucial task for agriculture. The international Diverfarming project (2017-2022), within the EU Horizon 2020 Program, focused on the impacts of crop diversification and low-input practices in all pedoclimatic regions of Europe. In this three-year experiment conducted in the Pannonian region, the impact of intercropping asparagus with different herbs on some provisioning and regulating ecosystem services was evaluated in the Kiskunság sand regions. Relying on findings based on a range of measured physical and chemical soil parameters and on crop yields and qualitative properties, advice was formulated for farmers. The message drawn from the experiment is somewhat ambiguous. The local farmers agree that crop diversification improves soil quality, but deny that it would directly influence farm competitiveness, which primarily depends on cultivation costs (such as fertilization, plant protection, and labour). Further analyses are needed to prove the long-term benefits of diversification through enriching soil microbial life and through the possible reduction of fertilizer use, while water demand is kept at a low level and the same crop-quality is ensured.

A single-point modeling approach for the intercomparison and evaluation of ozone dry deposition across chemical transport models (Activity 2 of AQMEII4)

A primary sink of air pollutants and their precursors is dry deposition. Dry deposition estimates differ across chemical transport models, yet an understanding of the model spread is incomplete. Here, we introduce Activity 2 of the Air Quality Model Evaluation International Initiative Phase 4 (AQMEII4). We examine 18 dry deposition schemes from regional and global chemical transport models as well as standalone models used for impact assessments or process understanding. We configure the schemes as single-point models at eight Northern Hemisphere locations with observed ozone fluxes. Single-point models are driven by a common set of site-specific meteorological and environmental conditions. Five of eight sites have at least 3 years and up to 12 years of ozone fluxes. The interquartile range across models in multiyear mean ozone deposition velocities ranges from a factor of 1.2 to 1.9 annually across sites and tends to be highest during winter compared with summer. No model is within 50 % of observed multiyear averages across all sites and seasons, but some models perform well for some sites and seasons. For the first time, we demonstrate how contributions from depositional pathways vary across models. Models can disagree with respect to relative contributions from the pathways, even when they predict similar deposition velocities, or agree with respect to the relative contributions but predict different deposition velocities. Both stomatal and nonstomatal uptake contribute to the large model spread across sites. Our findings are the beginning of results from AQMEII4 Activity 2, which brings scientists who model air quality and dry deposition together with scientists who measure ozone fluxes to evaluate and improve dry deposition schemes in the chemical transport models used for research, planning, and regulatory purposes.

Firework smoke: Impacts on urban air quality and deposition in the human respiratory system

Particle number concentrations and size distributions resulting from the firework displays held in Budapest, Hungary every year on St. Stephen's Day were studied over a period of seven years. In the year most impacted, the total particle number concentration reached its peak measured level of 369 × 10³ cm^-3 5 min after the end of the display, and returned to the pre-event state within 45 min. The fireworks increased hourly mean concentrations by a factor of 5-6, whereas the concentrations in the diameter range of 100-1000 nm, in which the magnitude of the increase was the greatest, were elevated by a factor of 20-25. An extra particle size mode at 203 nm was manifested in the size distributions as result of the fireworks. The PM₁₀ mass concentrations at peak firework influence and as 1-h mean increased 123 and 58 times, respectively, relative to the concentration before the display. The smoke was characterised by a relatively short overall atmospheric residence time of 25 min. Spatiotemporal dispersion simulations revealed that there were substantial vertical and horizontal concentration gradients in the firework plume. The affected area made up a large part of the city. Not only the spectators of the display at the venue and nearby areas, but the population located further away downwind of the displays and more distant, large and populous urban quarters were affected by the plume and its fallout. The fireworks increased the deposition rate in the respiratory system of females by a factor of 4, as a conservative estimate. The largest surface density deposition rates were seen in the segmental and sub-segmental bronchi, which represents an excessive risk to health. Compared to adults, children were more susceptible to exposure, with the maximum surface density deposition rates in their case being three times those of adults in the trachea.

Open photoacoustic cell for concentration measurements in rapidly flowing gas

High temporal resolution concentration measurements in rapid gas flows pose a serious challenge for most analytical instruments. The interaction of such flows with solid surfaces can generate excessive aero-acoustic noise making the application of the photoacoustic detection method seemingly impossible. Yet, the fully open photoacoustic cell (OC) has proven to be operable even when the measured gas flows through it at a velocity of several m/s. The OC is a slightly modified version of a previously introduced OC based on the excitation of a combined acoustic mode of a cylindrical resonator. The noise characteristics and analytical performance of the OC are tested in an anechoic room and under field conditions. Here we present the first successful application of a sampling-free OC for water vapor flux measurements.

Stable isotope data of daily precipitation during the period of 2013-2017 from K-puszta (regional background monitoring station), Hungary

Precipitation was collected on daily basis at K-puszta regional background monitoring station located near Kecskemét, in the western part of the Great Hungarian Plain, between 1 April 2013 and 31 December 2017 for stable hydrogen and oxygen analyses. The sample collection period covered 24 hours, from 07:00 to 07:00 h LT (Local Time) the next day. Stable hydrogen and oxygen isotope composition of the daily precipitation samples were measured using a Liquid Water Isotope Analyser (LWIA-24d) manufactured by Los Gatos Research Ltd. The dataset includes 472 stable isotopic data representing the continuation of the beforehand monitoring started in 2012 [1]. The dataset provides a unique opportunity to combine daily meteorological data and stable isotope composition of daily precipitation which can help to improve our understanding of the processes and factors at relatively high resolution that govern δD and δ¹⁸O values of the precipitation. In addition, the dataset can be used as an isotope hydrological benchmark in comparison with stable isotope dataset obtained from surface- and groundwater or other sources (e.g. climate proxies, agricultural products). Thus, research related to isotope hydrology, agriculture, paleoclimate can benefit from this dataset. Interpretation of this dataset focusing on the relationship between meteorological factors and stable isotope composition of precipitation is in progress.

Observation of wave-driven air–water turbulent momentum exchange in a large but fetch-limited shallow lake

Abstract. Wind-induced waves play a key role in air–sea momentum and heat exchange. Fetch-limited shallow lakes differ significantly from open ocean circumstances since the wave field is characterized by young and growing waves that (i) are steeper and can collapse by white-capping at lower wind speeds, and (ii) travel with lower phase velocity. Consequently, momentum (and heat) flux estimation methods arising from oceanographic observations cannot be directly applied; however, few attempts have been made to describe air–water turbulent exchange in case of large, but still fetch-limited shallow lakes. Within a Croatian-Hungarian measurement campaign, turbulent flux measurements were performed in Lake Balaton. Momentum and heat fluxes were measured with eddy-covariance technique at an offshore station, while waves were simultaneously recorded with underwater acoustic surface tracking. Momentum fluxes were also recorded at two further stations closer to the shore. In this study, we analyze the measured wind stress and surface waves to reveal surface drag in case of highly fetch-limited conditions. We compare our results with relevant model formulations that attempt to estimate momentum flux using different wave state parameterizations (i.e. wave age and wave slope modified Charnock formulations) and show that derived drag and roughness length parameterizations differ significantly from oceanographic formulas.

Analog Site Experiment in the High Andes-Atacama Region: Surface Energy Budget Components on Ojos del Salado from Field Measurements and WRF Simulations

Remote sensing data are abundant, whereas surface in situ verification of atmospheric conditions is rare on Mars. Earth-based analogs could help gain an understanding of soil and atmospheric processes on Mars and refine existing models. In this work, we evaluate the applicability of the Weather Research and Forecasting (WRF) model against measurements from the Mars analog High Andes-Atacama Desert. Validation focuses on the surface conditions and on the surface energy budget. Measurements show that the average daily net radiation, global radiation, and latent heat flux amount to 131, 273, and about 10 W/m², respectively, indicating extremely dry atmospheric conditions. Dynamically, the effect of topography is also well simulated. One of the main modeling problems is the inaccurate initial soil and surface conditions in the area. Correction of soil moisture based on in situ and satellite soil moisture measurements, as well as the removal of snow coverage, reduced the surface skin temperature root mean square error from 9.8°C to 4.3°C. The model, however, has shortcomings when soil condition modeling is considered. Sensible heat flux estimations are on par with the measurements (daily maxima around 500 W/m²), but surface soil heat flux is greatly overestimated (by 150-500 W/m²). Soil temperature and soil moisture diurnal variations are inconsistent with the measurements, partially due to the lack of water vapor representation in soil calculations.

Computation of daily Penman–Monteith reference evapotranspiration in the Carpathian Region and comparison with Thornthwaite estimates

Abstract. The Pannonian Basin Experiment (PannEx) is a Regional Hydroclimate Project (RHP) of the World Climate Research Programme (WCRP) Global Energy and Water Exchanges (GEWEX) Project. A gridded meteorological dataset is available for the PannEx region as part of the CarpatClim database, which consists of homogenized and harmonized daily meteorological observations for several climate parameters with 0.1∘ spatial resolution in the period of 1961–2010. The estimation of the Penman–Monteith reference evapotranspiration (ET0) on the daily scale was performed for the CarpatClim grid as one of the first results in the PannEx initiative. This study compares the already accessible Thornthwaite estimates of potential evapotranspiration (PET_Th) on the monthly scale to the newly derived Penman–Monteith estimates. The comparison is made on an annual and seasonal basis for the 50-year period. The distribution of both estimates is influenced by geographical location and orographic features. The annual time series are similar but the regional-average annual values of ET0 are ∼80 mm greater than the Thornthwaite estimate in the whole CarpatClim region. The relative bias and root mean square error was computed as well. The classical Thornthwaite method underestimates the ET0 by more than 20 % over extensive regions for selected grid points at elevations lower than 200 m in the Pannonian Basin. The slope of the fitted linear trend indicate increasing reference evapotranspiration in the Pannonian/Carpathian Basin due to climate change.

[Results of surgical treatment of hiatal hernia]

BACKGROUND

Hiatus hernias are considered as the most prominent form of diaphragmatic hernias. The passage is defined through the oesophageal hiatus, resulting in a superdiaphragmatic displacement of parts of the stomach or the complete stomach, respectively. In our work we investigated the treatment of partial thoracic stomach with both open and minimally invasive surgical procedures emphasising the view on operating data, the success of the surgery and recurrence rates. Patients with mesh insertion for hernia defect closures were considered separately.

MATERIAL AND METHOD

94 Patients were treated in the period from 01.01.2003 to 01.06.2010. The ratio male/female was 2 : 1. The median age was 66 years. All data were prospectively collected by means of surgical protocols and data from the central patient records and analysed retrospectively. The statistical analyses were performed with SPSS 18.0 (SPSS Inc., Chicago, IL, USA). Any existing significances were determined using the T-test.

RESULTS

Of the 94 patients, 65 were operated laparoscopically. In the case of nine patients an initial laparoscopic surgery had to be changed to an open procedure. The reasons for switching surgical procedures were splenic bleeding in the case of 2 patients, intestinal injury due to perforation by the trocar in one case and unclear surgical situs in 6 cases. The postoperative complication rate was 24 %. The main reasons were a delayed achievement of passage. The mortality rate was 0 %. The comparison between laparoscopic and open groups showed, by comparable complication and recurrence rates, a shorter recovery time in favour of patients operated on laparoscopically. Additionally it can be stated that a bridge closure with mesh (ePTFE) had no significant influence on the postoperative outcome. Therefore we cannot confirm the postulated poor postoperative results of other groups.

CONCLUSION

In summary, the clear trend in the surgical treatment of hiatus hernias is to minimally invasive surgery. Only for patients with multiple previous operations, who are expected to have strong adhesions, the operation with comparable morbidity and mortality rates can also be planned primarily as open. In this case, however, longer postoperative recovery times must be expected. Large defects can be treated with comparable complication and recurrence rates by mesh insertion (ePTFE).

Comparison of particulate number concentrations in three Central European capital cities

Number size distributions of atmospheric aerosol particles in the mobility diameter range from 10 to 1000 nm were determined in Budapest, Prague and Vienna for a one-year-long period. Particle number concentrations in various size fractions, their diurnal and seasonal variations, mean size distributions and some properties of new particle formation events were derived and compared. Yearly median particle number concentrations for Budapest, Prague and Vienna were 10.6×10(3), 7.3×10(3) and 8.0×10(3) cm(-3). Differences were linked to the different pollution levels of the cities, and to diverse measurement environments and local conditions. Mean contributions of ultrafine particles (particles with a mobility diameter <100 nm) to the total number concentration were 80%, 84% and 74% for Budapest, Prague and Vienna, thus these particles represent an overwhelming share of all particles in each city. Seasonal variation of particle number concentrations was not obvious. Diurnal variations of particles with a diameter between 100 and 1000 nm (N(100-1000)) exhibited similar shape for the cities, which was related to the time-activity pattern of inhabitants and regional influences. The structure of the diurnal variation for ultrafine particles was also similar. It contained a huge morning peak in each city which was explained by emissions from vehicular traffic. The second peak was shifted from afternoon rush hours to late evenings as a result of the daily cycling in meteorological parameters. The character of the measurement site also influenced the diurnal variation. Diurnal variation of the mean ratio of ultrafine particles to N(100-1000) clearly revealed the presence and importance of new particle formation and subsequent growth in urban environments. Nucleation frequencies in Budapest and Prague were 27% and 23%, respectively on a yearly time scale. They showed a minimum in winter for both places, while the largest nucleation activity was observed in spring for Budapest, and in summer for Prague.

Storage induced apoptosis of peripheral blood mononuclear cells obtained from leucoreduction system chambers

BACKGROUND AND OBJECTIVES

Recently, it was reported that leucocytes obtained from leucoreduction system chambers (LRSCs) after plateletapheresis show excellent quality due to culture of dendritic cells. This study analysed apoptosis of mononuclear cells derived from LRSCs of single platelet units (SPUs) and double platelet units (DPUs) during storage.

MATERIALS AND METHODS

This randomized prospective study compared eighteen single and double platelet units produced with the Trima Accel cell separator. Buffy coat was drained from the LRSCs and analysed after 1, 6, 24, 48 and 72 h. CD45+ lymphocytes and CD14+ monocytes cells as well as Annexin-V+ and 7-AAD+ mononuclear cells were measured by flow cytometry.

RESULTS

The WBC concentration of LRSCs obtained from SPUs and DPUs differed significantly (SPUs: 0·93 ± 0·32 ×10(5) per μl WBCs; DPUs: 1·71 ± 0·55 ×10(5) per μl WBCs; P<0·001). Processed blood volume (PBV) correlated significantly with WBC concentration (r(2)=0·75, P<0·001). Fifty percent of monocytes were Annexin-V-positive 1 h after production decreasing to 30% during 24 h of storage. Compared to that, the part of late apoptotic or necrotic PBMCs increased later on, after 24 h. After 24 h, Annexin-V- and 7-AAD-positive, late apoptotic and necrotic lymphocytes and monocytes doubled.

CONCLUSION

PBMCs stored in autologous plasma in PVC-bags at room temperature did not show an increase of 7-AAD-positive PBMCs during 24 h prior to cell processing but increased significantly thereafter.