Classical Aerosol Research Articles

The Theory of Self-Regulation of Parasitary Systems and COVID-19

Background. The COVID-19 pandemic once again confirmed the correctness of the theory of Academician V.D. Belyakov, according to which the basis for the development of the epidemic process is a phase change in the heterogeneity of the biological properties of the interacting populations of the pathogen and humans. In accordance with the theory of self-regulation of parasitic systems, changes are associated not only with genetic variability, but also with other polydeterminant characteristics of the pathogen: when new genovariants appeared, SARS-CoV-2 became less pathogenic for humans, but more contagious. This circumstance is important not only for theoretical, but also for practical epidemiology, as it makes it possible to predict the direction of development of the epidemic situation.
 Aims — to evaluate the manifestations of the epidemic process of the new coronavirus infection COVID-19 through the prism of the theory of self-regulation of parasitic systems.
 Methods. An epidemiological retrospective analysis of the incidence of COVID-19 was carried out, including the study of absolute and intensive incidence rates per 100,000 population, the dynamics of changes in the properties of the coronavirus population, and the identification of SARS-CoV-2 genovariants for the period from 03.2020 to 04.2023. To analyze SARS-CoV-2 genovariants at various stages of the pandemic, we used sequencing data presented on the SARS-CoV-2 genome information aggregation platform Virus Genome Aggregator of Russia (VGARus) — more than 248 thousand genetic sequences.
 Results. During the pandemic, there have been seven ups and downs in the incidence of COVID-19. During the period of circulation in the human population and adaptation to a new host, a significant amount of data has accumulated on the evolutionary changes in the SARS-CoV-2 genome, taking into account the trends in the acquisition of new epidemiological properties.
 Conclusion. An analysis of the manifestations of the epidemic process of COVID-19, as a classic aerosol anthroponosis, confirmed the correctness of the theory of Academician V.D. Belyakov, according to which the basis of its development is a phase change in the heterogeneity of the biological properties of the interacting populations of the pathogen and humans, based on negative feedback in the process of self-regulation.

Non-line-of-sight ultraviolet transmission coverage in non-precipitating, foggy, and rainy weather.

Sensitivity to weather conditions is the principal limitation of free-space optical communication. However, for the scattering based ultraviolet (UV) non-line-of-sight (NLOS) communication, the atmospheric scattering effect functions as an attenuation factor and potentially as a performance enhancer. To investigate the UV NLOS transmission coverage under different weather conditions, we employ the Mie Theory in conjunction with classical aerosol and hydrometeor particle models to estimate the absorption coefficient, the scattering coefficient, and the scattering phase function. We then use these atmospheric parameters combined with a range estimation model to determine the coverage of the UV NLOS communication for specified path loss. Simulation results reveal that in non-precipitating weather, poorer visibility correlates with broader coverage. In foggy conditions, the coverage range in light fog exceeds that in fog-free environments; however, as fog intensity increases, the coverage range decreases. Rain enhances the coverage range; and heavier precipitation results in a larger coverage area.

Experimental validation of simplified radionuclide transport bubble scrubbing code in sodium coolant pool

Solid radionuclides released following fuel pin failure may become entrained in gaseous fission products and be rapidly transported through the coolant pool to the cover gas region. Sensitivity studies on radionuclide transport have identified this potential pathway as one of both high concern and high uncertainty. The simplified radionuclide transport scrubbing code utilizes classical aerosol scrubbing mechanisms to model this phenomenon and predict aerosol masses reaching the cover gas region. This paper serves to validate this code in a sodium environment while conducting a parametric study to analyze the effects of aerosol size, bubble size, pool temperature, pool depth, aerosol density, and aerosol concentration. Through a series of experimental tests, it was determined that aerosol sizes ranging from 0.001 to 1.0 µm are of primary concern as aerosols in this range have a ratio of aerosol mass entering the sodium pool from the fuel pin to aerosol mass exiting the sodium pool to the cover gas region of less than 10. The experimental results were found to match the trends found in the scrubbing model closely, but significantly more scrubbing was seen experimentally. Decreasing bubble size and increasing pool depth and aerosol density were all found to increase scrubbing both experimentally and theoretically. Pool temperature was found to have a negligible effect on scrubbing amounts; however, this was largely due to a subsequent increase in bubble size corresponding to increasing temperatures which offset the increase in scrubbing due to increased temperature. Varying aerosol concentration was found to have no effect on scrubbing ratios. A final series of tests was conducted for a more prototypic fuel pin failure with a heterogenous bubble swarm. From these tests, it was found that the experimental scrubbing quantities were larger than for the single bubble case. Overall, it was found that the simplified bubble transport scrubbing code accurately models the trends of the bubble scrubbing but provides a conservative estimate of scrubbing quantities. Model limitations fail to model the complex phenomena present for fission product scrubbing via bubble transport, but match trends seen experimentally.

Quantifying the Long-Term MODIS Cloud Regime Dependent Relationship between Aerosol Optical Depth and Cloud Properties over China

Aerosols modify cloud properties and influence the regional climate. The impacts of aerosols on clouds differ for various cloud types, but their long-term relationships have not been fully characterized on a cloud regime basis. In this study, we quantified the cloud regime-dependent relationship between aerosol optical depth (AOD) and cloud properties over China using Moderate-Resolution Imaging Spectroradiometer (MODIS) data from 2002 to 2019. Daily clouds in each 1° by 1° grid were categorized into seven cloud regimes based on the “k-means” clustering algorithm. Overall, the cloud height increased, the cloud thickness and liquid water path increased, and the total cloud cover decreased for all cloud regimes during the study period. Linear correlations between AOD and cloud properties were found within stratocumulus, deep convective, and high cloud regimes, showing consistency with the classic aerosol–cloud interaction paradigms. Using stepwise multivariable linear regression, we found that the meteorological factors dominated the variation of cloud top pressure, while AOD dominated the variation of total cloud cover for most cloud regimes. There are regional differences in the main meteorological factors affecting the cloud properties.

UNATTACHED 212PB FRACTION IN THE WORKER'S BREATHING ZONE AT HIGH THORON CONCENTRATIONS.

Classical aerosol physics predicts that it is impossible to observe noticeable values of the unattached fraction of decay products of thoron at typical concentrations of aerosol particles. The experimental data have shown that the unattached fraction of the thoron decay products in a monazite storage facility is in the range 0.3-0.6. This effect is caused by local increase in air exchange near the inlet of the sampling device at high 220Rn concentrations. It was found that a dynamic shift between the unattached and attached thoron decay products is also observed in the worker's breathing zone at a high concentration of thoron. The 212Pb unattached fraction in worker's breathing zone was ~0.4. It demonstrates that when evaluating inhalation exposure to the products of the decay of thoron, it is necessary to take into account the increase of the 212Pb unattached fraction in the worker's breathing zone.

Application of a multi-layer systems toxicology framework for in vitro assessment of the biological effects of Classic Tobacco e-liquid and its corresponding aerosol using an e-cigarette device with MESH\u2122 technology

We previously proposed a systems toxicology framework for in vitro assessment of e-liquids. The framework starts with the first layer aimed at screening the potential toxicity of e-liquids, followed by the second layer aimed at investigating the toxicity-related mechanism of e-liquids, and finally, the third layer aimed at evaluating the toxicity-related mechanism of the corresponding aerosols. In this work, we applied this framework to assess the impact of the e-liquid MESH Classic Tobacco and its aerosol compared with that of cigarette smoke (CS) from the 3R4F reference cigarette. In the first layer, we evaluated the cytotoxicity profile of the MESH Classic Tobacco e-liquid (containing humectants, nicotine, and flavors) and its Base e-liquid (containing humectant and nicotine only) in comparison with total particulate matter (TPM) of 3R4F CS using primary bronchial epithelial cell cultures. In the second layer, the same culture model was used to explore changes in specific markers using high-content screening assays to identify potential toxicity-related mechanisms induced by the MESH Classic Tobacco and Base e-liquids beyond cell viability in comparison with the 3R4F CS TPM-induced effects. Finally, in the third layer, we compared the impact of exposure to the MESH Classic Tobacco or Base aerosols with 3R4F CS using human organotypic air–liquid interface buccal and small airway epithelial cultures. The results showed that the cytotoxicity of the MESH Classic Tobacco liquid was similar to the Base liquid but lower than 3R4F CS TPM at comparable nicotine concentrations. Relative to 3R4F CS exposure, MESH Classic Tobacco aerosol exposure did not cause tissue damage and elicited lower changes in the mRNA, microRNA, and protein markers. In the context of tobacco harm reduction strategy, the framework is suitable to assess the potential-reduced impact of electronic cigarette aerosol relative to CS.

Marine aerosol fluxes determined by simultaneous measurements of eddy covariance and gradient method

In this paper the results of the aerosol flux measurements in near water boundary layer are presented. Measurements were conducted using two micrometeorological methods in the southern Baltic Sea region. The preliminary results of comparisons of two methods are discussed. The eddy covariance (EC) method is shown as a method for the calibration of the gradient method (GM). The reason for proceeding with such calibration is to show that the GM, which is an indirect measuring method, is comparable with a direct method such as the EC. In the EC measurements the condensation particle counter (CPC, measuring range 0.05 - 3 m with 1 Hz counting speed) and the Research Anemometer (50 Hz measurement speed) were used. For the GM, a Classical Scattering Aerosol Spectrometer was applied (measuring range from 0.5 to 47 m diameter, within 36 measuring channels). Data from scientific cruises of the r/v Oceania in the southern Baltic Sea between 2008 and 2011 were analyzed.

An Efficient Algorithm Scheme for Implementing the TEMOM for Resolving Aerosol Dynamics

This paper presents a new algorithm scheme for implementing the Taylor-series expansion method of moments (TEMOM), which is a general method for solving the population balance equation. Instead of deriving moment ordinary differential equations (ODEs) for particular aerosol dynamics, the new numerical algorithm develops a subroutine that corresponds to types of kernels of aerosol dynamics rather than a particular kernel. Consequently, the TEMOM can be conveniently applied to types of dynamics rather than a particular dynamics, and the derivation from the PBE to moment ODEs is avoided. A key aspect to the new algorithm scheme is that the particle kernels are written in a general form, allowing for a universal expression of aerosol dynamics. The closure of ODEs for moments was accomplished by implementing a new Taylor-series expansion closure function with two varying parameters H and ϕ, which enables the TEMOM applicable to any type of moment sequence. The feasibility of the new algorithm scheme was verified by comparing it with other recognized methods for six classic aerosol dynamics. The new algorithm scheme makes the TEMOM much easier to be used for users as compared to its original version (Aerosol Sci Tech 49(2015):1021–1036). The idea of the algorithm scheme can be applied to other non-quadrature-based methods of moments.

Modeling the influences of aerosols on pre-monsoon circulation and rainfall over Southeast Asia

Abstract. We conduct several sets of simulations with a version of NASA's Goddard Earth Observing System, version 5, (GEOS-5) Atmospheric Global Climate Model (AGCM) equipped with a two-moment cloud microphysical scheme to understand the role of biomass burning aerosol (BBA) emissions in Southeast Asia (SEA) in the pre-monsoon period of February–May. Our experiments are designed so that both direct and indirect aerosol effects can be evaluated. For climatologically prescribed monthly sea surface temperatures, we conduct sets of model integrations with and without biomass burning emissions in the area of peak burning activity, and with direct aerosol radiative effects either active or inactive. Taking appropriate differences between AGCM experiment sets, we find that BBA affects liquid clouds in statistically significantly ways, increasing cloud droplet number concentrations, decreasing droplet effective radii (i.e., a classic aerosol indirect effect), and locally suppressing precipitation due to a deceleration of the autoconversion process, with the latter effect apparently also leading to cloud condensate increases. Geographical re-arrangements of precipitation patterns, with precipitation increases downwind of aerosol sources are also seen, most likely because of advection of weakly precipitating cloud fields. Somewhat unexpectedly, the change in cloud radiative effect (cloud forcing) at surface is in the direction of lesser cooling because of decreases in cloud fraction. Overall, however, because of direct radiative effect contributions, aerosols exert a net negative forcing at both the top of the atmosphere and, perhaps most importantly, the surface, where decreased evaporation triggers feedbacks that further reduce precipitation. Invoking the approximation that direct and indirect aerosol effects are additive, we estimate that the overall precipitation reduction is about 40% due to the direct effects of absorbing aerosols, which stabilize the atmosphere and reduce surface latent heat fluxes via cooler land surface temperatures. Further refinements of our two-moment cloud microphysics scheme are needed for a more complete examination of the role of aerosol–convection interactions in the seasonal development of the SEA monsoon.

Impacts of increasing the aerosol complexity in the Met Office global numerical weather prediction model

Abstract. The inclusion of the direct and indirect radiative effects of aerosols in high-resolution global numerical weather prediction (NWP) models is being increasingly recognised as important for the improved accuracy of short-range weather forecasts. In this study the impacts of increasing the aerosol complexity in the global NWP configuration of the Met Office Unified Model (MetUM) are investigated. A hierarchy of aerosol representations are evaluated including three-dimensional monthly mean speciated aerosol climatologies, fully prognostic aerosols modelled using the CLASSIC aerosol scheme and finally, initialised aerosols using assimilated aerosol fields from the GEMS project. The prognostic aerosol schemes are better able to predict the temporal and spatial variation of atmospheric aerosol optical depth, which is particularly important in cases of large sporadic aerosol events such as large dust storms or forest fires. Including the direct effect of aerosols improves model biases in outgoing long-wave radiation over West Africa due to a better representation of dust. However, uncertainties in dust optical properties propagate to its direct effect and the subsequent model response. Inclusion of the indirect aerosol effects improves surface radiation biases at the North Slope of Alaska ARM site due to lower cloud amounts in high-latitude clean-air regions. This leads to improved temperature and height forecasts in this region. Impacts on the global mean model precipitation and large-scale circulation fields were found to be generally small in the short-range forecasts. However, the indirect aerosol effect leads to a strengthening of the low-level monsoon flow over the Arabian Sea and Bay of Bengal and an increase in precipitation over Southeast Asia. Regional impacts on the African Easterly Jet (AEJ) are also presented with the large dust loading in the aerosol climatology enhancing of the heat low over West Africa and weakening the AEJ. This study highlights the importance of including a more realistic treatment of aerosol–cloud interactions in global NWP models and the potential for improved global environmental prediction systems through the incorporation of more complex aerosol schemes.

Inverse problem for aerosol particle size distribution using SPSO associated with multi-lognormal distribution model

Abstract A numerical study, used for particle size distributions of several classical aerosol types, is conducted in this paper. By improving the log-normal distribution model in previous paper, we employ the stochastic particle swarm optimization (SPSO) algorithm associated with a multi-lognormal distribution model. The nonambiguity and robustness of SPSO with this model is validated. We recover particle size distributions of two classical aerosol types using the measured AOT data (at wavelengths λ = 0.400, 0.690, 0.870, 1.020 μm) obtained from AERONET at different time. The results show that the model of this paper presents characteristics of aerosol particle size distributions at different regions and time. And this model shows good practicability to distinguish aerosol types and calculate particle size distributions.

Chemical Aerosol Engineering as a Novel Tool for Material Science: From Oxides to Salt and Metal Nanoparticles

Aerosol nanotechnology has rapidly evolved in the past years. This fascinating technology has resulted in the development of functional nanomaterials providing novel solutions in industrial applications. The extensive research on the physical understanding of gas phase processes has strongly contributed to the present industrial use of single and mixed oxides and the design of industrial aerosol reactors. Recent advances have shown that chemical aerosol engineering can be established on the interface between classical aerosol science and chemical engineering. The emerging new methods give access to a much broader class of functional materials including salt and metal nanoparticles. The latter implies that aerosol production units can now be considered as chemical reactors. The incorporation of thermodynamic considerations and chemical kinetics in the modelling of gas phase processes will further boost the development of aerosol engineering and will provide deeper understanding of the fundamentals of parti...

The science of aerosol delivery in cystic fibrosis

Aerosolized drugs are universally used for treatment of cystic fibrosis airway disease. Inhalation can increase topical efficacy and reduce systemic exposure and toxicity of many drugs. A wide variety of inhaled drugs already exist with many more in the therapeutic pipeline. Understanding the principles of aerosol delivery and how aerosol devices function is important in designing the best therapeutic regimens for CF patients. The variables that determine where an aerosol deposits are numerous and complex. Important aerosol-related variables include particle-size distribution, hygroscopic properties, viscosity and surface tension of the drug. Patient-related variables include inspired flow rate, tidal volume, respiratory rate, breath-holding, upper airway anatomy, lower airways obstruction, and the cognitive and physical ability to use the device. These factors vary widely between patients of different age groups and disease severities, and cause the high variability in drug delivery seen with aerosol drugs. Classic aerosol delivery devices like metered dose inhalers and dry-powder inhalers are small, portable, and have short treatment times. However, they are limited by small drug payloads and user technique problems. Jet nebulizers are commonly used for CF drugs, are easy to operate, require no special breathing pattern, and can deliver very large quantities of drug. However, they require a power or air source, cleaning and sanitizing, and are relatively time consuming. Recently, novel aerosol delivery systems and formulations have been developed to improve delivery efficiency and reduce variability and delivery time. These new systems can ease the treatment burden and improve adherence and outcomes in cystic fibrosis. Pediatr Pulmonol. 2008; 43:S5–S17. © 2008 Wiley-Liss, Inc.

ORILAM, a three‐moment lognormal aerosol scheme for mesoscale atmospheric model: Online coupling into the Meso‐NH‐C model and validation on the Escompte campaign

Classical aerosol schemes use either a sectional (bin) or lognormal approach. Both approaches have particular capabilities and interests: the sectional approach is able to describe every kind of distribution, whereas the lognormal one makes assumption of the distribution form with a fewer number of explicit variables. For this last reason we developed a three‐moment lognormal aerosol scheme named ORILAM to be coupled in three‐dimensional mesoscale or CTM models. This paper presents the concept and hypothesis of a range of aerosol processes such as nucleation, coagulation, condensation, sedimentation, and dry deposition. One particular interest of ORILAM is to keep explicit the aerosol composition and distribution (mass of each constituent, mean radius, and standard deviation of the distribution are explicit) using the prediction of three‐moment (m0, m3, and m6). The new model was evaluated by comparing simulations to measurements from the Escompte campaign and to a previously published aerosol model. The numerical cost of the lognormal mode is lower than two bins of the sectional one.

Aerosol Remote Sensing Using Ground-Based Measurements and POLDER Airborne Sensor above Coastal Waters

We conducted in 1994 and 1995 several airborne campaigns with an aircraft version of the POLDER (POLarization and Directionality of Earth Reflectance) instrument. We flew over the Straits of Dover. The main goal of this activity was to see how well we can characterize the atmospheric aerosols using POLDER data in order to achieve atmospheric corrections for ocean color purposes. We also set up atmospheric measurements (solar extinction, sky radiance, and degree of polarization) on which we tested classical aerosol models (Junge size distribution; Shettle and Fenn, 1979) for retrieval. For standard meteorological visibilities, such models allow correct matching of the measurements. For most turbid days, it is shown that a submicron particles haze can be superposed to the continental aerosol background. But we indicated that the SF models enable a good retrieval of the measurements. They thus appear relevant to describe more complex situations. Classically, we first used POLDER images to select an aerosol model based on the spectral dependence of the aerosol reflectance between the red and the infrared for which the water is dark offshore of the Straits. Compared again to the SF models, the spectral dependence observed differ substantially by large angular variations. A detailed analysis showed that these large dispersions are not related to instrumental noise but to natural variation of the aerosols and to residual errors in the Fresnel reflection correction. By averaging, we can also propose SF models. Both ground-based and POLDER-derived aerosol models are consistent in terms of retrieval of the atmospheric functions required for atmospheric corrections. We also tried less successfully a selection based on the polarized reflectance which is a POLDER capability.

A New Technique to Measure the Mobility Size of Ultrafine Radioactive Particles

ABSTRACT The 218Po clusters formed during radon decay in well controlled composition atmospheres are too small to be detected by a classical aerosol detection device such as a condensation nuclei counter. In this work we modified the first order version of the SMEC (spectrometre de mobilite electriques circulaire) and made it able to detect such particles/clusters. The geometry of this radial flow electric mobility analyzer is well adapted for ultrafine clusters measurement because of the short particle residence time and hence lower effects of diffusion. The major modification of this device was the detection system. At the exit of the SMEC, a filter and an alpha particle detector holder were mounted. The airflow containing the particles is drawn through the system when the particles exiting the SMEC are trapped on the filter. An appropriate radioactivity detector mounted directly opposite the filter can separate and count the 218Po particles/clusters. We have used this electrostatic size discrimination ...

Effect of the inner scale of turbulence on the atmospheric modulation transfer function

The effect of the inner scale of turbulence on the atmospheric modulation transfer function (MTF) is analyzed. It is shown that owing to this effect the turbulence MTF has all the main features of the overall measured atmospheric MTF, including different behaviors in the low- and high-frequency ranges, a knee, and dependence on the wavelength. It is also shown that the mismatches between the overall measured atmospheric MTF and the predicted turbulence MTF might be eliminated by use of a theoretical model with a finite inner scale of turbulence for the turbulence MTF and an accurate interpretation of the optical measurements of the refractive-index structure characteristic. Therefore no revision of the classical aerosol MTF theory is required to interpret the measured data.

Imaging through the atmosphere: practical instrumentation-based theory and verification of aerosol modulation transfer function

Recent experimental measurements of overall atmospheric modulation transfer function (MTF) indicate a significant difference between overall atmospheric and turbulence MTF’s except often at midday, when turbulence is strong. We suggest a physical explanation for these results that essentially relates to a practical instrumentation-based atmospheric aerosol MTF that is a modification of the classical aerosol MTF theory. Based on radiative transfer theory, this practical approach takes into account the effect of finite field of view, finite dynamic sensitivity, and finite spatial bandwidth of every existing imaging system. These generally limit the scattering angles of received light to values far less than the diffraction limit for aerosols, thereby decreasing blur radius and increasing spatial frequency bandwidth. This can explain the broadening of the aerosol MTF from that theoretically expected. We discuss the asymptote value that the measured aerosol MTF approaches at high spatial frequencies, which is significantly higher than the theoretical prediction of turbid medium transmittance. An important conclusion that we derive is that the aerosol MTF is often the dominant part in the actual overall atmospheric MTF. In addition, there seems to be an inescapable trade-off between image resolution and image irradiance. The system designer must choose between imaging of faint and bright objects at the expense of image quality or imaging of either faint or bright objects with improved image quality. The concepts here are basic to all long-range imaging through the atmosphere.

Essential oils of Labiatae for controlling honey bee varroosis

AbstractThe efficiency of Labiatae essential oils was compared with a classical aerosol treatment, including the acaricidic substance amitraz at the 0.25 concentration. The tested concentrations of the experimental mixture were 1% of thyme (Thymus vulgaris L.) and 0.5% of sage (Salvia officinalis L.). These products were also injected into each colony by the aerosol way for one minute. 4 applications in an interval of 3 or 4 days constitute the treatment. The dead mites (Varroa jacobsoni Oud.) were counted everyday. The number of surviving mites was estimated by means of a fluvalinate control treatment. No difference in the global efficiency was found for the moderately infested colonies (less than 1300 mites, a few mutilated pupae), which contained a small brood area. A weak grade of post‐therapeutic residues in honey was only detected by gas chromatography just after aerosol administration.RésuméTraitement de la varroose de l'abeille par les huiles essentielles de LabiéesLes essais de terrain présentés portent sur une comparaison de l'efficacité d'un mélange de deux huiles essentielles (Thymus vulgaris L. et Salvia officinalis L.) par rapport à l'amitraze. Ces produits sont mis en émulsion dans l'eau à la concentration des 0.25% pour l'amitraze, de 1% pour le thym et 0.5% pour la sauge et administrés dans la ruche par aérosol chaud pendant une minute, en 4 applications à 3 ou 4 jours d'intervalle. Les acariens Varroa jacobsoni Oud. morts sont recueillis quotidiennement. Après le traitement expérimental, le nombre d'acariens survivants est estimé par application de fluvalinate, la surface du couvain et la présence de nymphes mutilées sont aussi notées. L'efficacité du mélange d'huiles essentielles est égale à celle de l'amitraze, si les colonies sont moyennement parasitées (moins de 1300 acariens). Le niveau de résidus post‐thérapeutiques est proche de la limite de détection.ZusammenfassungÄtherische Öle aus Labiaten zur Bekämpfung der Honigbienen‐VarroatosisEs wurde die Wirkung von zwei ätherischen Ölen aus Labiaten im Vergleich mit einem klassischen Bekämpfungsaerosol von 0,25% Amitraz untersucht. Die getesteten Konzentrationen der experimentellen Mischungen betrugen 1% aus Thymus vulgaris und 0,5% aus Salvia officinalis. Diese Produkte wurden ebenso wie das Aerosol 1 Minute lang in den Bienenstock eingeführt. Die Behandlung bestand aus 4 Applikationen in Intervallen von 3 oder 4 Tagen. Die toten Milben von Varroa jacobsoni wurden täglich gezählt. Die Zahl der überlebenden Milben wurde durch eine zusätzliche Kontrollbegiftung mit Fluvalinat bestimmt. Es ergab sich für die verschieden behandelten Kolonien kein Unterschied in der Gesamtwirkung (weniger als 1300 Milben, wenige verstümmelte Puppen). Post‐therapeutische Rückstände geringen Grades im Honig wurden gaschromatografisch nur unmittelbar nach der Aerosol‐Anwendung nachgewiesen.

Marine condensation nucleus generation inferred from whitecap simulation tank results

The condensation nuclei (CN) produced during a set of experiments in the Whitecap Simultation Tank at University College, Galway, were measured with a TSI 3020 nucleus counter. The total number of CN produced per breaking wave event was 3.5 ± 0.5 × 107 for a seawater temperature near 15°C. The CN production per unit area of whitecap (108 m−2) and the previously observed whitecap time decay constant of ∼3.5 s implies a whitecap CN flux Fw of ∼2.8 + 0.9 × 107 m−2 s−1. This can be combined with the whitecap coverage W versus 10 m wind speed U relation of E. C. Monahan and I. O'Muircheartaigh (1980), W(U) = 3.84 × 10−6 U3.41, to estimate the general oceanic CN flux F0 = WFW. For U = 10 m s−1, this relation gives W = 1%, and thus F0 is ∼2.8 × 105 m−2 s−1. Using the same Whitecap Simulation Tank and a PMS classical aerosol spectrometer, E. C. Monahan et al. (1982) determined that the whitecap flux Fw of giant particles (radii > 1 μm at relative humidity = 80%) was ∼2 × 106 m−2S−1. Clearly, most of the CN produced by this whitecap simulation are of submicron size, and this was also the case in the model breaking wave experiments of R. J. Cipriano et al. (1983). Both laboratory whitecap simulations suggest that the ocean contributes significantly to the CN and cloud condensation nuclei populations of the marine atmospheric boundary layer far from land.