Current areas that require further boundary layer theory, measurements, and/or modeling include: 1 nature and theory of turbulent boundary layer structure and flows; 2 the turbulence closure problem; ...3 stability dependence of the Prandtl and critical Richardson numbers; 4 airflows within and above urban and other complex canopies; 5 air-sea-ice interactions; and, 6 improvement of PBL schemes in operational and environmental security models. The TKE equation, in combination with both downgradient formulations for turbulent fluxes and the Kolmogorov closure hypothesis for eddy viscosity K^sub M^, conductivity K^sub H^, and diffusivity K^sub D^ (all taken proportional to TKE^sup 1/2^ times mixing length), predicts unrealistic decay rates of turbulence at Richardson numbers (Ri) greater than a critical value Ri^sub c^.
Risks associated with dust hazards are often underappreciated, a gap between the knowledge pool and public awareness that can be costly for impacted communities. This study reviews the emission ...sources and chemical, physical, and biological characteristics of airborne soil particles (dust) and their effects on human and environmental health and safety in the Pan‐American region. American dust originates from both local sources (western United States, northern Mexico, Peru, Bolivia, Chile, and Argentina) and long‐range transport from Africa and Asia. Dust properties, as well as the trends and interactions with criteria air pollutants, are summarized. Human exposure to dust is associated with adverse health effects, including asthma, allergies, fungal infections, and premature death. In the Americas, a well‐documented and striking effect of soil dust is its association with Coccidioidomycosis, commonly known as Valley fever, an infection caused by inhalation of soil‐dwelling fungi unique to this region. Besides human health, dust affects environmental health through nutrients that increase phytoplankton biomass, contaminants that diminish water supply and affect food (crops/fruits/vegetables and ready‐to‐eat meat), spread crop and marine pathogens, cause Valley fever among domestic and wild animals, transport heavy metals, radionuclides and microplastics, and reduce solar and wind power generation. Dust is also a safety hazard to road transportation and aviation, in the southwestern US where blowing dust is one of the deadliest weather hazards. To mitigate the harmful effects, coordinated regional and international efforts are needed to enhance dust observations and prediction capabilities, soil conservation measures, and Valley fever and other disease surveillance.
Plain Language Summary
Soil particles suspended in the air, commonly known as dust, impose substantial risks to many sectors of society, including human health, environmental health, transportation safety and the general economy. This work focuses on the dust effects in the Pan‐American region, where the knowledge is rather fragmented, but impacts are costly. Dust in the Americas either comes from local sources or is transported by winds from Asia and Africa. Human exposure to dust can cause adverse health effects, such as asthma, Valley fever, and even death. Dust affects the environment by supplying nutrients to ecosystems, contaminating water and food, spreading pathogens, microplastics, heavy metals and radionuclides, and reducing solar and wind power generation. Dust is also one of the deadliest weather hazards particularly in the southwestern United States. Finally, the measures to mitigate these harmful effects include coordinated dust prediction and early warning, soil conservation, and public health surveillance.
Key Points
Human exposure to dust has been associated with adverse health effects, including asthma, fungal infections, and premature death
Dust provides nutrients to ecosystems, pollutes water and food, spreads pathogens and radionuclides, and reduces solar generation
Dust is a major safety hazard to road transportation, aviation, and marine navigation
Dust particles from high latitudes have a potentially large local, regional, and global significance to climate and the environment as short-lived climate forcers, air pollutants, and nutrient ...sources. Identifying the locations of local dust sources and their emission, transport, and deposition processes is important for understanding the multiple impacts of high-latitude dust (HLD) on the Earth’s systems. Here, we identify, describe, and quantify the source intensity (SI) values, which show the potential of soil surfaces for dust emission scaled to values 0 to 1 concerning globally best productive sources, using the Global Sand and Dust Storms Source Base Map (G-SDS-SBM). This includes 64 HLD sources in our collection for the northern (Alaska, Canada, Denmark, Greenland, Iceland, Svalbard, Sweden, and Russia) and southern (Antarctica and Patagonia) high latitudes. Activity from most of these HLD sources shows seasonal character. It is estimated that high-latitude land areas with higher (SI ≥ 0.5), very high (SI ≥ 0.7), and the highest potential (SI ≥ 0.9) for dust emission cover > 1 670 000 km2 , > 560 000 km2 , and > 240 000 km2 , respectively. In the Arctic HLD region (≥ 60◦ N), land area with SI ≥ 0.5 is 5.5 % (1 035 059 km2), area with SI ≥ 0.7 is 2.3 % (440 804 km2), and area with SI ≥ 0.9 is 1.1 % (208 701 km2). Minimum SI values in the northern HLD region are about 3 orders of magnitude smaller, indicating that the dust sources of this region greatly depend on weather conditions. Our spatial dust source distribution analysis modeling results showed evidence supporting a northern HLD belt, defined as the area north of 50◦ N, with a “transitional HLD-source area” extending at latitudes 50–58◦ N in Eurasia and 50–55◦ N in Canada and a “cold HLD-source area” including areas north of 60◦ N in Eurasia and north of 58◦ N in Canada, with currently “no dust source” area between the HLD and low-latitude dust (LLD) dust belt, except for British Columbia. Using the global atmospheric transport model SILAM, we estimated that 1.0 % of the global dust emission originated from the high-latitude regions. About 57 % of the dust deposition in snow- and ice-covered Arctic regions was from HLD sources. In the southern HLD region, soil surface conditions are favorable for dust emission during the whole year. Climate change can cause a decrease in the duration of snow cover, retreat of glaciers, and an increase in drought, heatwave intensity, and frequency, leading to the increasing frequency of topsoil conditions favorable for dust emission, which increases the probability of dust storms. Our study provides a step forward to improve the representation of HLD in models and to monitor, quantify, and assess the environmental and climate significance of HLD.
Background. This study was initiated for the morphological comparison of two species of recently described Amur graylings collected in the unique zone of their sympatry. This provided an infrequent ...opportunity for the estimation of the species-specific morphological diversification not determined by environmental conditions dissimilarity. This study aimed to compare the seismosensory systems of two species of Amur grayling, the lower Amur grayling, Thymallus tugarinae Knizhin, Antonov, Safronov et Weiss, 2007, and yellow-spotted grayling, Thymallus flavomaculatus Knizhin, Antonov et Weiss, 2006, collected in sympatric habitats with the inclusion of the published data on other northeast Asia grayling species. Materials and methods. The comparative study was based on samples of T tugarinae and T. flavomaculatus specimens collected at species sympatric habitats in the middle stretch of the Anyuy River, one of the biggest tributaries of the Amur River. The lateral line system was stained, the topology was examined, and seismosensory system canal pores were counted. Differences in canal pore numbers between examined species were estimated with Wilcoxon signed-rank test. Also, cluster analysis was carried out. Results. Examined sympatric species were found to differ in the number of pores and secondary canaliculi topology but were similar to geographically distant grayling species. Conclusions. The results revealed sympatric morphological divergence of studied species and demonstrated parallelism of interspecies variability of examined features which are likely determined by conditions of species ecological optima. Comparative morphological analysis of the species and forms with questionable taxonomic status should be carried out using material that is collected in different parts of the habitation areal, paying special attention to the sympatry zones, if there are any such cohabitation regions, because the environmental factors have similar effects on all of the analysed species within such zones.
Aerosol inhalation delivery of ceftriaxone in mice was investigated. An ultrasonic nebulizer within the ranges of mean particle diameter 0.5–1.5 μm and mass concentration 0.01–0.6 μg/cm3 was used in ...inhalation experiments. Pharmacokinetic measurements were carried out using a nose-only chamber. Ceftriaxone concentration in blood serum and its mass in the lungs of mice were measured as a function of time using high-performance liquid chromatography. The body-delivered dose was within the range 3–5 mg/kg. The antibacterial effect of aerosolized ceftriaxone was investigated for mice infected with Klebsiella pneumoniae 82 and Staphylococcus aureus ATCC 25 953. The survival rate for infected mice after the treatment with ceftriaxone aerosol revealed the high antibacterial efficiency of this kind of treatment.
The purpose of this study was to investigate the relationship between possible long-distance transport of birch pollen and episodes of elevated concentration in Denmark. By analysis of a twenty-six ...year (1980-2006) time-series of bi-hourly birch pollen counts from two sites (Copenhagen and Viborg) episodes of elevated counts (more than 100 grains) were identified in fewer than 2% of cases. Trajectory analysis showed that such episodes are primarily associated with long-distance transport from Eastern Europe and Scandinavia (43 and 33% of events, respectively); the lowest contribution originated from the British Isles. Long-term episodes (as in 1993 and 2006) occurred when atmospheric conditions favored long-distance transport from several source regions in succession.
Megacities, air quality and climate Baklanov, Alexander; Molina, Luisa T.; Gauss, Michael
Atmospheric environment (1994),
February 2016, 2016-02-00, Letnik:
126
Journal Article
Recenzirano
The rapid urbanization and growing number of megacities and urban complexes requires new types of research and services that make best use of science and available technology. With an increasing ...number of humans now living in urban sprawls, there are urgent needs of examining what the rising number of megacities means for air pollution, local climate and the effects these changes have on global climate. Such integrated studies and services should assist cities in facing hazards such as storm surge, flooding, heat waves, and air pollution episodes, especially in changing climates. While important advances have been made, new interdisciplinary research studies are needed to increase our understanding of the interactions between emissions, air quality, and regional and global climates. Studies need to address both basic and applied research and bridge the spatial and temporal scales connecting local emissions and air pollution and local weather, global atmospheric chemistry and climate. This paper reviews the current status of studies of the complex interactions between climate, air quality and megacities, and identifies the main gaps in our current knowledge as well as further research needs in this important field of research.
•Climate, air quality and megacities interactions: gaps in knowledge, research needs.•Urban hazards: pollution episodes, storm surge, flooding, heat waves, public health.•Global climate change affects megacities' climate, environment and comfort.•Growing urbanization requires integrated weather, environment and climate monitoring systems.•New generation of multi-scale models and integrated urban services are needed.
This paper discusses some of the differences between online and offline approaches for both air quality forecasting and numerical weather prediction, and argues in favor of an eventual migration to ...integrated modeling systems that allow two-way interactions of physical and chemical processes. Recent studies are used that directly compared online and offline simulations to discuss possible shortcomings for both air quality and weather forecasting. The disadvantages of offline approaches are easy to show for air quality forecasting. On the other hand, a positive impact on short to medium range weather forecasts that is significant enough to justify an implementation at operational weather forecasting centers is more difficult to prove, and may initially only come through an improvement of the meteorological data assimilation. Eventually though, a migration to an integrated modeling system will provide new opportunities for weather prediction modelers as well. The simulation of chemical species will allow identification of shortcomings in currently used forecast models as well as lead to better use of meteorological data assimilation.
Real-time air quality forecasting (RT-AQF), a new discipline of the atmospheric sciences, represents one of the most far-reaching development and practical applications of science and engineering, ...poses unprecedented scientific, technical, and computational challenges, and generates significant opportunities for science dissemination and community participations. This two-part review provides a comprehensive assessment of the history, current status, major research and outreach challenges, and future directions of RT-AQF, with a focus on the application and improvement of three-dimensional (3-D) deterministic RT-AQF models. In Part I, major milestones in the history of RT-AQF are reviewed. The fundamentals of RT-AQF are introduced. Various RT-AQF techniques with varying degrees of sophistication and skills are described comparatively. Among all techniques, 3-D RT-AQF models with online-coupled meteorology–chemistry and their transitions from mesoscale to unified model systems across scales represent a significant advancement and would greatly enhance understanding of the underlying complex interplay of meteorology, emission, and chemistry from global to urban scales in the real atmosphere. Current major 3-D global and regional RT-AQF models in the world are reviewed in terms of model systems, component models, application scales, model inputs, forecast products, horizontal grid resolutions, and model treatments of chemistry and aerosol processes. An important trend of such models is their coupling with an urban model or a computational fluid dynamic model for urban/local scale applications at 1 km or less and with an exposure model to provide real-time public health assessment and exposure predictions. Evaluation protocols are described along with examinations of current forecasting skills and areas with large biases of major RT-AQF models.
► A comprehensive review for real-time air quality forecasting (RT-AQF). ► Major milestones in the history of RT-AQF. ► Assessment of major RT-AQF techniques. ► A detailed review of 3-D RT-AQF models. ► Evaluation protocols and review of current forecasting skills of RT-AQF models.
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