Among the many impacts of COVID-19, the pandemic led to improved air quality conditions in the countries under quarantine due to the shutdown of industries, drastically reduced traffic, and lockdowns. Meanwhile, the w...
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Among the many impacts of COVID-19, the pandemic led to improved air quality conditions in the countries under quarantine due to the shutdown of industries, drastically reduced traffic, and lockdowns. Meanwhile, the western United States, particularly the coastal areas from Washington to California, received much less precipitation than normal during early 2020. Is it possible that this reduction in precipitation was driven by the reduced aerosols due to the coronavirus? Here we show that the reduction in aerosols resulted in higher temperatures (up to similar to 0.5 degrees C) and generally lower snow amounts but cannot explain the observed low precipitation amounts over this region. In addition to an assessment of the effects of the coronavirus-related reduction in aerosols on precipitation across the western United States, our findings also provide basic information on the potential impacts different mitigation efforts aimed at reducing anthropogenic aerosols would have on the regional climate.
Caustic singularities of the spatial distribution of particles in turbulent aerosols enhance collision rates and accelerate coagulation. Here we investigate how and where caustics form at weak particle inertia, by ana...
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Caustic singularities of the spatial distribution of particles in turbulent aerosols enhance collision rates and accelerate coagulation. Here we investigate how and where caustics form at weak particle inertia, by analyzing a three-dimensional Gaussian statistical model for turbulent aerosols in the persistent limit, where the flow varies slowly compared with the particle relaxation time. In this case, correlations between particle- and fluid-velocity gradients are strong and caustics are induced by large strain-dominated excursions of the fluid-velocity gradients. These excursions must cross a characteristic threshold in the plane spanned by the invariants Q and R of the fluid-velocity gradients. Our method predicts that the most likely way to reach this threshold is by a unique optimal fluctuation that propagates along the Vieillefosse line 27R2/4+Q3=0. We determine the shape of the optimal fluctuation as a function of time and show that it is dominant in numerical statistical-model simulations even for moderate particle inertia.
In recent years, cannabis vaporizer cartridges have increased in popularity and availability, and there are concerns regarding exposure to heavy-metal compounds from their use. The physical components of the cartridge...
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In recent years, cannabis vaporizer cartridges have increased in popularity and availability, and there are concerns regarding exposure to heavy-metal compounds from their use. The physical components of the cartridge devices themselves have been implicated as a potential source of metal exposure, but it is not known if these metals migrate into the inhalable vapor. This study analyzes the components of vaporizer cartridges for 10 different metals and also collects aerosol mixtures from 13 randomly purchased commercially available cannabis cartridges from Washington State to compare their elemental profiles. Results indicate that chromium, copper, nickel, as well as smaller amounts of lead, manganese, and tin migrate into the cannabis oil and inhaled vapor phase, resulting in a possible acute intake of an amount of inhaled metals above the regulatory standard of multiple governmental bodies. Noncartridge heating methods of cannabis flower and concentrate were compared, and results indicate that the heating device itself is a source of metal contamination. As safety and compliance testing regulations evolve, it will be important to include more than the standard As, Cd, Hg, and Pb to the list of regulated metals.
Wildfires, bamboo and aerosols are becoming topics of research interest in the south-western Amazon because their impact on local ecosystems may influence the future climate on Earth. Their interaction is particularly...
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Wildfires, bamboo and aerosols are becoming topics of research interest in the south-western Amazon because their impact on local ecosystems may influence the future climate on Earth. Their interaction is particularly important because it can self-amplify, potentially leading to unexpected consequences such as a decrease in carbon storage capacity due to the dominance of bamboo ecosystems after fire. This article synthesizes the discrete pieces of knowledge on each of these components to develop a conceptual model of wildfires-bamboo-aerosols relationships and to identify future research agendas. The interaction between wildfires and bamboo is controversial because the answer to whether bamboo significantly enhances the probability of wildfire events remains elusive. However, the ongoing deforestation of the Amazon is a possible trigger for increased interactions between wildfires and bamboo. A positive feedback likely exists in an area where aerosols produced by wildfires induce subsequent wildfires. aerosols can form an oversupply of cloud condensation nuclei, which delays rainfall. Alternatively, they can absorb solar radiation and cool the Earth's surface, which suppresses cloud formation. Little research has been conducted on the relationship between bamboo and aerosols in the Amazon. However, there is some indirect evidence that bamboo can be a significant producer of aerosols, which then affect wildfires by changing rainfall patterns. Our integrative approach will help to identify the triangular relationship between wildfires, bamboo and aerosols.
Studies on aerosol pollution monitoring gained considerable attention in recent decade, particularly, during the episodes of naturally and anthropogenically induced change in emission. The episodic events of PM10 aero...
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A wide-angle camera based imaging lidar was used to measure altitude dependent aerosol single angle side scattering. Aerosol extinction was derived for several continuous hours to monitor spatial and temporal distribu...
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We characterize here the airborne lipids (beta/omega-hydroxy fatty acids: FAs) specific to soil microbes and plant waxes over suburban Tokyo in simultaneously collected aerosols and rainwater from spring and autumn se...
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We characterize here the airborne lipids (beta/omega-hydroxy fatty acids: FAs) specific to soil microbes and plant waxes over suburban Tokyo in simultaneously collected aerosols and rainwater from spring and autumn seasons. Air mass trajectories in spring revealed transport mostly from the North Pacific but with a lesser contribution from East Asia and vice versa in autumn. Low-molecular-weight (<= C-20) beta-hydroxy FAs are more abundant, suggesting their contribution from soil/marine microbial organic matter. The occurrence of high-molecular-weight (>C-20;the subscript denotes carbon chain length) compounds and, in particular, high concentrations of even-C homologs in C-9-C-30 omega-hydroxy FAs revealed their origin from higher plant waxes. Besides, a gradual decrease in beta/omega-hydroxy FA loadings in spring suggests their particle bound nature and efficient removal by wet-scavenging. However, this pattern was not obvious for autumn rains likely because of lateral advection of air parcels. Estimated endotoxin levels of ambient Gram-negative bacteria based on C-10-C-18 beta-hydroxy FAs for the autumn season (median: 14 ng m(-3)) were higher than the inhalable human exposure limit set by the Dutch committee (9 ng m(-3)). These results have implications for understanding endotoxin exposure on human health in Japanese cities during early winter.
Chemical ionization mass spectrometry (CIMS) is a powerful tool for on-line characterization of atmospheric trace species and reveal of new atmospheric oxidation mechanisms. The applications of CIMS promoted understan...
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Chemical ionization mass spectrometry (CIMS) is a powerful tool for on-line characterization of atmospheric trace species and reveal of new atmospheric oxidation mechanisms. The applications of CIMS promoted understanding of new particle formation and the roles of trace species in air-quality issues. In the past decade or so, various new techniques in ion sources have been applied to improve sensitivity and replace radioactive sources. Moreover, researchers have developed multiple sampling inlets for CIMS to meet the measurement demand of reactive trace species. In this study, we discussed these developments and reviewed a limited number of representative applications of CIMS, including trace highly reactive gaseous pollutants, aerosols and highly oxygenated organic molecules. In particular, we summarized the choice of reagent ions, the influencing factors of the sensitivity, and the strategies in improving instrument sensitivity. This review summarizes CIMS instrument developments and its applications from an appreciation of instrument technology developing perspectives.
CONSPECTUS: aerosols are ubiquitous in the atmosphere and profoundly affect climate systems and human health. To gain more insights on their broad impacts, we need to comprehensively understand the fundamental propert...
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CONSPECTUS: aerosols are ubiquitous in the atmosphere and profoundly affect climate systems and human health. To gain more insights on their broad impacts, we need to comprehensively understand the fundamental properties of atmospheric aerosols. Since aerosols are multiphase, a dispersion of condensed matter (solid particles or liquid droplets, hereafter particles) in gas, partitioning of volatile matter between the condensed and the gas phases is one defining characteristic of aerosols. For example, water content partitioning under different relative humidity conditions, known as aerosol hygroscopicity, has been extensively investigated in the past decades. Meanwhile, partitioning of volatile organic or inorganic components, which is referred to as aerosol volatility, remains understudied. Commonly, a bulk solution system is treated as a single phase, with volatility mainly determined by the nature of its components, and the composition partitioning between solution and gas phase is limited. aerosols, however, comprise an extensive gas phase, and their volatility can also be induced by component reactions. These reactions occurring within aerosols are driven by the formation of volatile products and their continuous partitioning into the gas phase. As a consequence, the overall aerosol systems exhibit prominent volatility. Noteworthily, such volatility induced by reactions is a phenomenon exclusively observed in the multiphase aerosol systems, and it is trivial in bulk solutions due to the limited extent of liquid-gas partitioning. Take the chloride depletion in sea salt particles as an example. Recent findings have revealed that chloride depletion can be caused by reactions between NaCl and weak organic acids, which release HCl into the gas phase. Such a reaction can be described as a strong acid displaced by a weak acid, which is hardly observed in bulk phase. Generally, this unique partitioning behavior of aerosol systems and its potential to alter aerosol compo
Aerosol particles in coastal areas result from a complex mixing between sea-spray aerosols locally generated at the sea surface by breaking waves and a continental component issued from natural and/or anthropogenic so...
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Aerosol particles in coastal areas result from a complex mixing between sea-spray aerosols locally generated at the sea surface by breaking waves and a continental component issued from natural and/or anthropogenic sources. The aim of this paper is to study how the aerosols mix in the coastal marine atmosphere to evaluate the impact of the background pollution on the atmospheric aerosols. To this end, we have carried out a qualitative analysis of particulate matter sampled at two French coastal areas using a non-destructive methodology combining scanning electron microscopy (SEM)/X-ray fluorescence, transmission electron microscopy (TEM), X-ray diffraction, and Raman spectroscopy. Our analysis shows a dominant contribution of anthropogenic aerosols through strong levels of submicronic carbon soot and sulfate particles, even observed when the aerosol is sampled during pure maritime-air mass episodes. Our results also evidence the non-mixing between sea-spray, mainly composed of coarse aerosol particles, and this anthropogenic particulate matter of smaller sizes.
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