Local Atmospheric Transport Research Articles

Modelling the dynamic gas/particle partitioning process of semi-volatile organic compounds emitted from point sources: Quantitative analysis and impact assessment

The deleterious impact of pollution point sources on the surrounding environment and human has long been a focal point of environmental research. When considering the local atmospheric dispersion of semi-volatile organic compounds (SVOCs) around the emission sites, it is essential to account the dynamic process for the gas/particle (G/P) partitioning, which involves the transition from an initial state to a steady state. In this study, we have developed a model that enables the prediction of the dynamic process for G/P partitioning of SVOCs, particularly considering the influence from emission. It is important to note that the dynamic processes of the concentrations of SVOCs in particle phase (CP) and in gas phase (CG) differ significantly. These differences arise due to the influence of two critical factors: particulate proportion of SVOCs in the emissions (ϕ0) and octanol-air partitioning coefficient (KOA). The validity of our model was assessed by comparing its predictions of the extremum value of the G/P partitioning quotient (KP) with the results obtained from the steady-state model. Remarkably, the characteristic time (tC), used to evaluate the timescale required for SVOCs to reach steady state, demonstrated different variations with KOA for CP and CG. Additionally, the values of tC were quite different for CP and CG, which were markedly influenced by ϕ0. For some SVOCs with high KOA values, it took approximately 35 h to reach steady state. Furthermore, it was found that the time to achieve 95 % of steady state (t95 ≈ 3tC) could reach approximately 105 h. This duration is sufficient for chemicals to disperse from their emission site to the surrounding areas. Therefore, it is crucial to consider the dynamic process of G/P partitioning in local atmospheric transport studies. Moreover, the influence of ϕ0 should be incorporated into future investigations examining the dynamic process of G/P partitioning.

Local atmospheric transport behaviors of representative radionuclides during the Fukushima accident: A 200-m-resolution cross-scale study from site to 20 km

Modeling of local atmospheric radionuclide transport is essential for nuclear emergency response. However, very few studies of the Fukushima Dai-ichi nuclear power plant (FDNPP) accident have focused on this topic because of the complex meteorology and the cross-scale transport behaviors from the site to 20 km of the FDNPP. In this study, both the local meteorology and transport behaviors were investigated at high resolution (200 m) using ensembles of different meteorology and models. Four wind fields calculated from onsite observations and three regional-scale meteorological fields (i.e., the 1-km ECMWF, 3-km and 1-km NHM-LETKF), and two transport models: the RIMPUFF Lagrangian puff model and the SPRAY particle model were considered and combined with each other. These eight simulations and their ensemble mean were analyzed based on onsite observations of wind and gamma dose rates, and local-scale observations of 137Cs concentration. Results revealed that at the site, the Onsite wind field which captured the frequently changing wind, best reproduced the onsite gamma dose rates with the grid resolution of 200 m. At the local scale (up to 20 km), the observations present a smoother temporal change. The wind fields assimilated with Japanese domestic observations presented advantageous performance, and the 1-km NHM-LETKF achieved the best score of the factor of 5 metric of 0.49 for the simulated 137Cs concentration. The SPRAY coupled with the three-dimensional (3D) convolution method and RIMPUFF showed better performance in simulating the onsite gamma dose rate and the local-scale concentration, respectively. The ensemble mean achieved robust metrics, better simulated the baseline of onsite gamma dose rates, and reproduced more peaks of local-scale concentration at the expense of peak value deviation.

Vliyaniye techeniy i atmosfernoy tsirkulyatsii na effektivnost' promysla khamsy v period yeye zimovki u Chernomorskogo poberezh'ya Krasnodarskogo kraya

Russian fishermen harvest European anchovy primarily off the Black Sea coast of the Krasnodar Territory during its wintering and wintering migrations. At wintering grounds, temperature conditions become a secondary factor in determining the behaviour of commercial concentration of European anchovy, with wind and currents being the primary factors. Therefore, the aim of this work is to determine the potential use of daily data on water circulation and local atmospheric transport in short-term (1–7 days) forecasting of European anchovy fishing in the Black Sea. The research used the European anchovy fishery monitoring materials for January – March 2019, as well as daily maps of the Black and Azov Seas level anomalies (from satellite altimetry data) and surface atmospheric pressure and temperature in Europe (analysis) for the mentioned period. The dynamics of the catch rate and its relation to altimetry and atmospheric transport indicators in the north-eastern part of the Black Sea were investigated using graphical and correlation methods. This analysis showed that the main factor contributing to increased catches is intensification of northwest currents in the coastal 60-km zone. The effect of atmospheric transport on fishing efficiency depends on the mesoscale eddy structure of the nearshore current field. In the presence of an intense northwest current in the fishing area, southwest atmospheric transports have a positive effect on fishing, while in the presence of an anticyclonic meander of currents, northeast atmospheric transports become effective. The presence of maximum significant relationships when the determinants of fishing performance are shifted by 1–7 days allows making short-term predictions of fishing efficiency.

Spatial distribution and temporal trend of airborne trace metal deposition in Albania studied by moss biomonitoring

This study describes the assessment of air quality in Albania using moss biomonitoring. The moss species, Hypnum cupressiforme (Hedw) sps., was used in this study. Mosses were collected during August and September 2015 at 55 sampling sites more or less homogeneously distributed over the entire territory of the country. The spatial distribution and temporal trends of trace metal atmospheric deposition were studied through the determination of twenty inorganic elements, Al, As, Ba, Ca, Cd, Co, Cr, Cu, Fe, Hg, K, Li, Mg, Mn, Na, Ni, Pb, Sr, V, and Zn. ICP-AES, AAS (As and Cd) and CV AAS (Hg) analysis were used to determine the concentration of the elements. The obtained data show significant differences in the spatial distribution of the elements derived from different emission sources. High emission loads of anthropogenic elements (Cr, Ni, Cu, As and Zn) were detected in the East, and of sea salt elements, particularly Na and K, in the Western coastal line. The distribution trend of the trace metals was studied by comparing the current data with the data of a similar study performed in 2010. Due to the differences in airborne metal concentrations, their scavenging ratios from the atmosphere to the terrestrial ecosystems, and their different uptake-leaching rates during wet and dry deposition respectively of 2015 and 2010 moss grown period, different concentration levels were found in 2010 and 2015 moss metal concentrations. The 2015 moss concentration levels of anthropogenic elements Cr, Ni, Cu, As, Zn and Na had increased, while K, Mg and Hg moss concentration data had declined. Other elements show non significant differences in mosses of both monitoring periods.The contamination levels that were evaluated by calculating the contamination factor (CF) for each element provided similar results for the 2015 and 2010 moss survey. Factor analysis (FA) was applied to identify the possible sources of elements in the 2015 moss samples. Five dominant factors were identified representing long-range and local atmospheric transport of wind-blown soil dust particles (F1); local emission from chromium industry and wind-blown mineral dust particles (F2); anthropogenic sources of traffic emission and wind-blown fine mineral dust particles derived from geogenic origin natural transport from the marine environment (F4); and long-range atmospheric deposition (F5). This study emphasis that moss biomonitoring combined with data analysis and inventory of emission sources are important tools to assess air quality in Albania.

Examination of local atmospheric transport of radioxenon in the Ottawa River Valley

Concentrations of the radioxenon isotopes 133Xe and 135Xe were measured as they were released from the stack at the Chalk River medical isotope production facility and were then measured at various sites in the Ottawa River Valley. Dispersion modeling was then used to model the local transport of these radioxenon isotopes between the production facility and the sampling locations. The ratio of 135Xe/133Xe was also examined using an ORIGEN-ARP model was used to understand what factors played a role in the 135Xe/133Xe ratio at the time of release by considering irradiation time, flux, and decay time prior to fractionation.

Isotopic and hydrogeochemical characterization of high-altitude karst aquifers in complex geological settings. The Ordesa and Monte Perdido National Park (Northern Spain) case study

The Ordesa and Monte Perdido National Park, located in the Southern Pyrenees, constitutes the highest karst system in Western Europe. No previous studies regarding its geochemical and isotopic groundwater characterization are available in this area. This work presents the results of field and sampling campaigns carried out between July 2007 and September 2013. The groundwater presents high calcium bicarbonate contents due to the occurrence of upper Cretaceous and lower Paleocene–Eocene carbonate materials in the studied area. Other relevant processes include dissolution of anhydrite and/or gypsum and incongruent dissolution of Mg-limestone and dolomite. The water stable isotopes (δ18O, δ2H) show that the oceanic fronts from the Atlantic Ocean are responsible for the high levels of precipitation. In autumn, winter, and spring, a deuterium excess is found in the recharge water, which could be related to local atmospheric transport of low-altitude snow sublimation vapour and its later condensation on the snow surface at higher altitude, where recharge is mostly produced. The recharge zones are mainly between 2500m and 3200ma.s.l. The tritium content of the water suggests short groundwater transit times. The isotopic composition of dissolved sulphate points to the existence of regional fluxes mixed with local discharge in some of the springs. This work highlights the major role played by the altitude difference between the recharge and discharge zones in controlling the chemistry and the vertical variability of the isotopic composition in high-altitude karst aquifers.

Identifying urban sources as cause of elevated grass pollen concentrations using GIS and remote sensing

Abstract. We examine here the hypothesis that during flowering, the grass pollen concentrations at a specific site reflect the distribution of grass pollen sources within a few kilometres of this site. We perform this analysis on data from a measurement campaign in the city of Aarhus (Denmark) using three pollen traps and by comparing these observations with a novel inventory of grass pollen sources. The source inventory is based on a new methodology developed for urban-scale grass pollen sources. The new methodology is believed to be generally applicable for the European area, as it relies on commonly available remote sensing data combined with management information for local grass areas. The inventory has identified a number of grass pollen source areas present within the city domain. The comparison of the measured pollen concentrations with the inventory shows that the atmospheric concentrations of grass pollen in the urban zone reflect the source areas identified in the inventory, and that the pollen sources that are found to affect the pollen levels are located near or within the city domain. The results also show that during days with peak levels of pollen concentrations there is no correlation between the three urban traps and an operational trap located just 60 km away. This finding suggests that during intense flowering, the grass pollen concentration mirrors the local source distribution and is thus a local-scale phenomenon. Model simulations aimed at assessing population exposure to pollen levels are therefore recommended to take into account both local sources and local atmospheric transport, and not to rely only on describing regional to long-range transport of pollen. The derived pollen source inventory can be entered into local-scale atmospheric transport models in combination with other components that simulate pollen release in order to calculate urban-scale variations in the grass pollen load. The gridded inventory with a resolution of 14 m is therefore made available as supplementary material to this paper, and the verifying grass pollen observations are additionally available in tabular form.