Omnipresence of biological material in the atmosphere

2007 ◽  
Vol 4 (4) ◽  
pp. 217 ◽  
Author(s):  
Ruprecht Jaenicke ◽  
Sabine Matthias-Maser ◽  
Sabine Gruber
Keyword(s):  
Atmospheric Aerosols ◽  
Atmospheric Aerosol ◽  
Biological Material ◽  
Total Mass ◽  
Large Fraction ◽  
Aerosol Particles ◽  
Climate Forcing ◽  
The Past ◽  
Biological Particles ◽  
Precipitation Formation

Environmental context. Atmospheric biological particles have been largely overlooked in the past. While some microorganisms have been studied, the majority of other biological particles have not. The presence of these particles might force us to view the atmospheric aerosol differently. Abstract. Measurements of biological particles in the atmosphere during the last decade indicate that the presence of these particles seems to have been underestimated by atmospheric scientists. On the average these primary aerosol particles might be present as much as 25% of the total mass (or number for particles with radius greater than 0.2 µm) concentration of the atmospheric aerosol. Such a large fraction certainly plays a major role in all processes affected by atmospheric aerosols, such as cloud and precipitation formation, climate forcing, visibility, turbidity, and so on. This disregard of the biological particles requires a new attitude in our opinion.

scholarly journals Sensitivity of atmospheric aerosol scavenging to precipitation intensity and frequency in the context of global climate change

2017 ◽  
Author(s):  
Pei Hou ◽  
Shiliang Wu ◽  
Jessica L. McCarty
Keyword(s):  
Climate Change ◽  
Global Climate Change ◽  
Atmospheric Aerosols ◽  
Atmospheric Aerosol ◽  
Model Simulation ◽  
Global Climate ◽  
Regional Scale ◽  
Precipitation Intensity ◽  
The Past ◽  
Precipitation Changes

Abstract. Wet deposition driven by precipitation is an important sink for atmospheric aerosols and soluble gases. We investigate the sensitivity of atmospheric aerosol lifetimes to precipitation intensity and frequency in the context of global climate change. Our study, based on the GEOS-Chem model simulation, shows that the removal efficiency and hence the atmospheric lifetime of aerosols have significantly higher sensitivities to precipitation frequencies than to precipitation intensities, indicating that the same amount of precipitation may lead to different removal efficiencies of atmospheric aerosols. Combining the long-term trends of precipitation patterns for various regions with the sensitivities of atmospheric aerosols lifetimes to various precipitation characteristics allows us to examine the potential impacts of precipitation changes on atmospheric aerosols. Analyses based on an observational dataset show that precipitation frequency in some regions have decreased in the past 14 years, which might increase the atmospheric aerosol lifetimes in those regions. Similar analyses based on multiple reanalysis meteorological datasets indicate that the precipitation changes over the past 30 years can lead to perturbations in the atmospheric aerosol lifetimes by 10 % or higher at the regional scale.

scholarly journals Review and uncertainty assessment of size-resolved scavenging coefficient formulations for snow scavenging of atmospheric aerosols

2013 ◽  
Vol 13 (6) ◽  
pp. 14823-14869 ◽  
Author(s):  
L. Zhang ◽  
X. Wang ◽  
M. D. Moran ◽  
J. Feng
Keyword(s):  
Atmospheric Aerosols ◽  
Atmospheric Aerosol ◽  
Collection Efficiency ◽  
Aerosol Particles ◽  
Field Measurements ◽  
Cross Sectional ◽  
Atmospheric Aerosol Particles ◽  
Order Of Magnitude ◽  
Snow Particle ◽  
Scavenging Coefficient

Abstract. Theoretical parameterizations for the size-resolved scavenging coefficient for atmospheric aerosol particles scavenged by snow (Λsnow) need assumptions regarding (i) snow particle–aerosol particle collection efficiency E, (ii) snow particle size distribution N(Dp), (iii) snow particle terminal velocity VD, and (iv) snow particle cross-sectional area A. Existing formulas for these parameters are reviewed in the present study and uncertainties in Λsnow caused by various combinations of these parameters are assessed. Different formulations of E can cause uncertainties in Λsnow of more than one order of magnitude for all aerosol sizes for typical snowfall intensities. E is the largest source of uncertainty among all the input parameters, similar to rain scavenging of atmospheric aerosols (Λrain) as was found in a previous study by Wang et al. (2010). However, other parameters can also cause significant uncertainties in Λsnow, and the uncertainties from these parameters are much larger than for Λrain. Specifically, different N(Dp) formulations can cause one-order-of-magnitude uncertainties in Λsnow for all aerosol sizes, as is also the case for a combination of uncertainties from both VD and A. In comparison, uncertainties in Λrain from N(Dp) are smaller than a factor of 5 and those from VD are smaller than a factor of 2. Λsnow estimated from one empirical formula generated from field measurements falls in the upper range of, or is slightly higher than, theoretically estimated values. The predicted aerosol concentrations obtained using different Λsnow formulas can differ by a factor of two for just a one-centimeter snowfall (liquid water equivalent of approximately 1 mm). It is likely that, for typical rain and snow event the removal of atmospheric aerosol particles by snow is more effective than removal by rain for equivalent precipitation amounts, although a firm conclusion requires much more evidence.

scholarly journals Changes in atmospheric aerosol loading retrieved from space based measurements during the past decade

2013 ◽  
Vol 13 (10) ◽  
pp. 26001-26041 ◽  
Author(s):  
J. Yoon ◽  
J. P. Burrows ◽  
M. Vountas ◽  
W. von Hoyningen-Huene ◽  
D. Y. Chang ◽  
...  
Keyword(s):  
Climate Change ◽  
Atmospheric Aerosols ◽  
Atmospheric Aerosol ◽  
Western Europe ◽  
Global Climate ◽  
Anthropogenic Sources ◽  
Radiation Balance ◽  
Industrialized Countries ◽  
Anthropogenic Pollutants ◽  
The Past

Abstract. Atmospheric aerosol, generated from natural and anthropogenic sources, plays a key role in regulating visibility, air quality, and acid deposition. It is directly linked to and impacts on human health. It also reflects and absorbs incoming solar radiation and thereby influences the climate change. The cooling by aerosols is now recognized to have partly masked the atmospheric warming from fossil fuel combustion emissions. The role and potential management of short-lived climate pollutants such as aerosol are currently a topic of much scientific and public debate. Our limited knowledge of atmospheric aerosol and its influence on the Earth's radiation balance has a significant impact on the accuracy and error of current predictions of the future global climate change. In the past decades, environmental legislation in industrialized countries has begun to limit the release of anthropogenic pollutants. In contrast, in Asia as a result of the recent rapid economic development, emissions from industry and traffic have increased dramatically. In this study, the temporal changes/trends of atmospheric aerosols, derived from the satellite instruments MODIS (on board Terra and Aqua), MISR (Terra), and SeaWiFS (OrbView-2) during the past decade, are investigated. Whilst the aerosol optical thickness, AOT, over Western Europe decreases (i.e. by up to about −40% from 2003 to 2008) and parts of North America, a statistically significant increase (about +34% in the same period) over East China is observed and attributed to both the increase in industrial output and the Asian desert dust.

scholarly journals Sensitivity of atmospheric aerosol scavenging to precipitation intensity and frequency in the context of global climate change

2018 ◽  
Vol 18 (11) ◽  
pp. 8173-8182 ◽  
Author(s):  
Pei Hou ◽  
Shiliang Wu ◽  
Jessica L. McCarty ◽  
Yang Gao
Keyword(s):  
Climate Change ◽  
Global Climate Change ◽  
Atmospheric Aerosols ◽  
Atmospheric Aerosol ◽  
Global Climate ◽  
Regional Scale ◽  
Precipitation Intensity ◽  
The Past ◽  
Long Term Trends ◽  
Precipitation Changes

Abstract. Wet deposition driven by precipitation is an important sink for atmospheric aerosols and soluble gases. We investigate the sensitivity of atmospheric aerosol lifetimes to precipitation intensity and frequency in the context of global climate change. Our sensitivity model simulations, through some simplified perturbations to precipitation in the GEOS-Chem model, show that the removal efficiency and hence the atmospheric lifetime of aerosols have significantly higher sensitivities to precipitation frequencies than to precipitation intensities, indicating that the same amount of precipitation may lead to different removal efficiencies of atmospheric aerosols. Combining the long-term trends of precipitation patterns for various regions with the sensitivities of atmospheric aerosol lifetimes to various precipitation characteristics allows us to examine the potential impacts of precipitation changes on atmospheric aerosols. Analyses based on an observational dataset show that precipitation frequencies in some regions have decreased in the past 14 years, which might increase the atmospheric aerosol lifetimes in those regions. Similar analyses based on multiple reanalysis meteorological datasets indicate that the changes of precipitation intensity and frequency over the past 30 years can lead to perturbations in the atmospheric aerosol lifetimes by 10 % or higher at the regional scale.

scholarly journals Review and uncertainty assessment of size-resolved scavenging coefficient formulations for below-cloud snow scavenging of atmospheric aerosols

2013 ◽  
Vol 13 (19) ◽  
pp. 10005-10025 ◽  
Author(s):  
L. Zhang ◽  
X. Wang ◽  
M. D. Moran ◽  
J. Feng
Keyword(s):  
Atmospheric Aerosols ◽  
Atmospheric Aerosol ◽  
Collection Efficiency ◽  
Aerosol Particles ◽  
Empirical Formulas ◽  
Cross Sectional ◽  
Atmospheric Aerosol Particles ◽  
Order Of Magnitude ◽  
Snow Particle ◽  
Scavenging Coefficient

Abstract. Theoretical parameterizations for the size-resolved scavenging coefficient for atmospheric aerosol particles scavenged by snow (Λsnow) need assumptions regarding (i) snow particle–aerosol particle collection efficiency E, (ii) snow-particle size distribution N(Dp), (iii) snow-particle terminal velocity VD, and (iv) snow-particle cross-sectional area A. Existing formulas for these parameters are reviewed in the present study, and uncertainties in Λsnow caused by various combinations of these parameters are assessed. Different formulations of E can cause uncertainties in Λsnow of more than one order of magnitude for all aerosol sizes for typical snowfall intensities. E is the largest source of uncertainty among all the input parameters, similar to rain scavenging of atmospheric aerosols (Λrain) as was found in a previous study by Wang et al. (2010). However, other parameters can also cause significant uncertainties in Λsnow, and the uncertainties from these parameters are much larger than for Λrain. Specifically, different N(Dp) formulations can cause one-order-of-magnitude uncertainties in Λsnow for all aerosol sizes, as is also the case for a combination of uncertainties from both VD and A. Assumptions about dominant snow-particle shape (and thus different VD and A) will cause an uncertainty of up to one order of magnitude in the calculated scavenging coefficient. In comparison, uncertainties in Λrain from N(Dp) are smaller than a factor of 5, and those from VD are smaller than a factor of 2. As expected, Λsnow estimated from empirical formulas generated from field measurements falls in the upper range of, or is higher than, the theoretically estimated values, which can be explained by additional processes/mechanisms that influence field-derived Λsnow but that are not considered in the theoretical Λsnow formulas. Predicted aerosol concentrations obtained by using upper range vs. lower range of Λsnow values (a difference of around two orders of magnitude in Λsnow) can differ by a factor of 2 for just a one-centimetre snowfall (liquid water equivalent of approximately 1 mm). Based on the median and upper range of theoretically generated Λsnow and Λsnow values, it is likely that, for typical rain and snow events, the removal of atmospheric aerosol particles by snow is more effective than removal by rain for equivalent precipitation amounts, although a firm conclusion requires much more evidence.

scholarly journals AN ASSESSMENT OF SEVERITY OF ENVIRONMENTAL AEROSOL PARTICLES DURING PRECIPITATION

2015 ◽  
Vol 4 (3) ◽  
pp. 81-95
Author(s):  
T. S. Verma ◽  
K. S. Madhava Rao ◽  
Shibu K. John
Keyword(s):  
Mathematical Model ◽  
Biomass Burning ◽  
Atmospheric Aerosols ◽  
Atmospheric Aerosol ◽  
Aerosol Particles ◽  
Carbon Dioxide Concentration ◽  
Objective Criterion ◽  
Different Seasons ◽  
Index Of Severity ◽  
The Impact

Africa is one of the sources of biomass burning emissions. It is estimated that about 6 million tons of fuel per day is consumed in the southern hemisphere. Biomass burning has an important contribution on aerosol particle concentrations in the atmosphere. Efforts have been made to conduct research in Gaborone to monitor the concentration of atmospheric aerosols in atmosphere. These studies were mainly confined to measurement of concentration of aerosols and establishing a relation with determinants such as carbon dioxide concentration, biomass burning, and precipitation among others. However, very little seems to have been done in relating the empirical data to a mathematical model or to study quantitatively the impact of precipitation on the concentration of aerosols larger than 0.3?m in the atmosphere. In this paper we provide an objective criterion for classifying measurements on concentration of atmospheric aerosol particles and build a mathematical model that helps us to understand variations in weekly aerosol concentrations in terms of their severity. We also construct an index of severity which when applied to different seasons under the study period indicates that precipitation significantly scavenges atmospheric aerosols.International Journal of Environment Volume-4, Issue-3, June-August 2015Page: 81-95

scholarly journals A combined particle trap/HTDMA hygroscopicity study of mixed inorganic/organic aerosol particles

2008 ◽  
Vol 8 (18) ◽  
pp. 5589-5601 ◽  
Author(s):  
A. A. Zardini ◽  
S. Sjogren ◽  
C. Marcolli ◽  
U. K. Krieger ◽  
M. Gysel ◽  
...  
Keyword(s):  
Citric Acid ◽  
Growth Factor ◽  
Ammonium Sulfate ◽  
Adipic Acid ◽  
Atmospheric Aerosols ◽  
Glutaric Acid ◽  
Large Fraction ◽  
Aerosol Particles ◽  
Organic Aerosol ◽  
Water Soluble

Abstract. Atmospheric aerosols are often mixtures of inorganic and organic material. Organics can represent a large fraction of the total aerosol mass and are comprised of water-soluble and insoluble compounds. Increasing attention was paid in the last decade to the capability of mixed inorganic/organic aerosol particles to take up water (hygroscopicity). We performed hygroscopicity measurements of internally mixed particles containing ammonium sulfate and carboxylic acids (citric, glutaric, adipic acid) in parallel with an electrodynamic balance (EDB) and a hygroscopicity tandem differential mobility analyzer (HTDMA). The organic compounds were chosen to represent three distinct physical states. During hygroscopicity cycles covering hydration and dehydration measured by the EDB and the HTDMA, pure citric acid remained always liquid, adipic acid remained always solid, while glutaric acid could be either. We show that the hygroscopicity of mixtures of the above compounds is well described by the Zdanovskii-Stokes-Robinson (ZSR) relationship as long as the two-component particle is completely liquid in the ammonium sulfate/glutaric acid system; deviations up to 10% in mass growth factor (corresponding to deviations up to 3.5% in size growth factor) are observed for the ammonium sulfate/citric acid 1:1 mixture at 80% RH. We observe even more significant discrepancies compared to what is expected from bulk thermodynamics when a solid component is present. We explain this in terms of a complex morphology resulting from the crystallization process leading to veins, pores, and grain boundaries which allow for water sorption in excess of bulk thermodynamic predictions caused by the inverse Kelvin effect on concave surfaces.

scholarly journals A combined particle trap/HTDMA hygroscopicity study of mixed inorganic/organic aerosol particles

2008 ◽  
Vol 8 (2) ◽  
pp. 5235-5268 ◽  
Author(s):  
A. A. Zardini ◽  
S. Sjogren ◽  
C. Marcolli ◽  
U. K. Krieger ◽  
M. Gysel ◽  
...  
Keyword(s):  
Citric Acid ◽  
Ammonium Sulfate ◽  
Adipic Acid ◽  
Atmospheric Aerosols ◽  
Glutaric Acid ◽  
Large Fraction ◽  
Aerosol Particles ◽  
Organic Aerosol ◽  
Water Soluble ◽  
Component Particle

Abstract. Atmospheric aerosols are often mixtures of inorganic and organic material. Organics can represent a large fraction of the total aerosol mass and are comprised of water-soluble and insoluble compounds. Increasing attention was paid in the last decade to the capability of mixed inorganic/organic aerosol particles to take up water (hygroscopicity). We performed hygroscopicity measurements of internally mixed particles containing ammonium sulfate and carboxylic acids (citric, glutaric, adipic acid) in parallel with an electrodynamic balance (EDB) and a hygroscopicity tandem differential mobility analyzer (HTDMA). The organic compounds were chosen to represent three distinct physical states. During hygroscopicity cycles covering hydration and dehydration measured by the EDB and the HTDMA, pure citric acid remained always liquid, adipic acid remained always solid, while glutaric acid could be either. We show that the hygroscopicity of mixtures of the above compounds is well described by the Zdanovskii-Stokes-Robinson (ZSR) relationship as long as the two-component particle is completely liquid in the ammonium sulfate/citric acid and in the ammonium sulfate/glutaric acid cases. However, we observe significant discrepancies compared to what is expected from bulk thermodynamics when a solid component is present. We explain this in terms of a complex morphology resulting from the crystallization process leading to veins, pores, and grain boundaries which allow for water sorption in excess of bulk thermodynamic predictions caused by the inverse Kelvin effect on concave surfaces.

Albumins as Embedding Media for Electron Microscopy

1969 ◽  
Vol 27 ◽  
pp. 422-423 ◽  
Author(s):  
J. L. Farrant ◽  
J. D. McLean
Keyword(s):  
Electron Microscopy ◽  
Electron Microscope ◽  
High Temperature ◽  
Biological Material ◽  
Globular Proteins ◽  
The Past ◽  
Antibody Staining ◽  
Thin Sectioning ◽  
Embedding Medium

For electron microscope techniques such as ferritin-labeled antibody staining it would be advantageous to have available a simple means of thin sectioning biological material without subjecting it to lipid solvents, impregnation with plastic monomers and their subsequent polymerization. With this aim in view we have re-examined the use of protein as an embedding medium. Gelatin which has been used in the past is not very satisfactory both because of its fibrous nature and the high temperature necessary to keep its solutions fluid. We have found that globular proteins such as the serum and egg albumins can be cross-linked so as to yield blocks which are suitable for ultrathin sectioning.

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