scholarly journals Internally mixed soot, sulfates, and organic matter in aerosol particles from Mexico City

2008 ◽  
Vol 8 (3) ◽  
pp. 9179-9207 ◽  
Author(s):  
K. Adachi ◽  
P. R. Buseck
Keyword(s):  
Organic Matter ◽  
Mexico City ◽  
Power Plants ◽  
Aerosol Particles ◽  
Radiation Budget ◽  
Cloud Formation ◽  
Multiple Sources ◽  
Soot Particles ◽  
Hygroscopic Properties ◽  
Individual Particles

Abstract. Soot particles are major aerosol constituents that result from emissions of burning of fossil fuel and biomass. Because they both absorb sunlight and contribute to cloud formation, they are an influence on climate on local, regional, and global scales. It is therefore important to evaluate their optical and hygroscopic properties and those effects on the radiation budget. Those properties commonly change through reaction with other particles or gases, resulting in complex internal mixtures. Using transmission electron microscopy, we measured ~8000 particles (25 samples) with aerodynamic diameters from 0.05 to 0.3 μm that were collected in March 2006 from aircraft over Mexico City (MC) and adjacent areas. More than 50% of the particles consist of internally mixed soot, organic matter, and sulfate. Imaging combined with chemical analysis of individual particles show that many are coated, consist of aggregates, or both. Coatings on soot particles can amplify their light absorption, and coagulation with sulfates changes their hygroscopic properties, resulting in shorter lifetime. Our results suggest that a mixture of materials from multiple sources such as vehicles, power plants, and biomass burning occurs in individual particles, thereby increasing their complexity. Through changes in their optical and hygroscopic properties, internally mixed soot particles have a greater effect on the regional climate than uncoated soot particles. Moreover, soot occurs in more than 60% of all particles in the MC plumes, suggesting its important role in the formation of secondary aerosol particles.

scholarly journals Internally mixed soot, sulfates, and organic matter in aerosol particles from Mexico City

2008 ◽  
Vol 8 (21) ◽  
pp. 6469-6481 ◽  
Author(s):  
K. Adachi ◽  
P. R. Buseck
Keyword(s):  
Organic Matter ◽  
Mexico City ◽  
Climate Models ◽  
Volume Fraction ◽  
Aerosol Particles ◽  
Regional Climate ◽  
Soot Volume Fraction ◽  
Soot Particles ◽  
Hygroscopic Properties ◽  
Almost All

Abstract. Soot particles, which are aggregated carbonaceous spherules with graphitic structures, are major aerosol constituents that result from burning of fossil fuel, biofuel, and biomass. Their properties commonly change through reaction with other particles or gases, resulting in complex internal mixtures. Using a transmission electron microscope (TEM) for both imaging and chemical analysis, we measured ~8000 particles (25 samples) with aerodynamic diameters from 0.05 to 0.3 μm that were collected in March 2006 from aircraft over Mexico City (MC) and adjacent areas. Most particles are coated, consist of aggregates, or both. For example, almost all analyzed particles contain S and 70% also contain K, suggesting coagulation and condensation of sulfates and particles derived from biomass and biofuel burning. In the MC plumes, over half of all particles contained soot coated by organic matter and sulfates. The median value of the soot volume fraction in such coated particles is about 15%. In contrast to the assumptions used in many climate models, the soot particles did not become compact even when coated. Moreover, about 80% by volume of the particles consisting of organic matter with sulfate also contained soot, indicating the important role of soot in the formation of secondary aerosol particles. Coatings on soot particles can amplify their light absorption, and coagulation with sulfates changes their hygroscopic properties, resulting in shorter lifetimes. Through changes in their optical and hygroscopic properties, internally mixed soot particles have a greater effect on the regional climate of MC than uncoated soot particles.

scholarly journals Haze types in Beijing and the influence of agricultural biomass burning

2010 ◽  
Vol 10 (17) ◽  
pp. 8119-8130 ◽  
Author(s):  
W. J. Li ◽  
L. Y. Shao ◽  
P. R. Buseck
Keyword(s):  
Organic Matter ◽  
Biomass Burning ◽  
Cloud Condensation Nuclei ◽  
Aerosol Particles ◽  
Fine Fraction ◽  
Northern China ◽  
Heterogeneous Reactions ◽  
Agricultural Biomass ◽  
Soot Particles

Abstract. Emissions from agricultural biomass burning (ABB) in northern China have a significant impact on the regional and global climate. The monthly average aerosol optical depth (AOD) at 550 nm in northern China in 2007 had a maximum of 0.7 in June. The AOD measurements are consistent with regional brown hazes that occurred at that time, which was a period of severe aerosol pollution. Aerosol particles were collected in urban Beijing from 12 to 30 June 2007, during a period of high haze, and studied using transmission electron microscopy with energy-dispersive X-ray spectrometry. The dominant particle types collected in the fine fraction (diameter <1 μm) were ammonium sulfate, soot, K2SO4, KNO3, and organic matter, except that the K salts were minor between 21 and 30 June. K-rich particles as tracers of biomass burning, together with wildfire maps, show that intense regional ABB in northern China contributed significantly to the regional haze between 12 and 20 June. We therefore grouped the episodes into type-1 and -2 haze, with the former occurring between 12 and 20 June and the latter between 21 and 30 June. After long-range transport, ABB particles in the type-1 haze exhibited marked changes in morphology, composition, and mixing state. KCl particles were absent, presumably having been converted by heterogeneous reactions to K2SO4 and KNO3. Soot particles were mixed with the other particle types. Abundant organic matter and soluble salts emitted by ABB increased their sizes during transport and resulted in more hygroscopic aerosol particles in downwind areas, becoming additional cloud condensation nuclei. The high AOD (average value 2.2) in Beijing during 12 to 20 June is partly explained by the hygroscopic growth of fine aerosol particles and by the strong absorption of internally mixed soot particles, both coming from regional ABB emissions. Therefore, it is important to consider the origins of the haze, which in turn leads to the different particle types.

scholarly journals Laser remote monitoring of hazardous substances emissions by ship power plants

2021 ◽  
pp. 75-81
Author(s):  
В.А. Туркин ◽  
Г.В. Игнатенко ◽  
И.А. Сарычев ◽  
Р.И. Джиоев
Keyword(s):  
Laser Radiation ◽  
Electromagnetic Waves ◽  
Power Plants ◽  
Aerosol Particles ◽  
Laser System ◽  
Mie Scattering ◽  
Hazardous Substances ◽  
Laser Method ◽  
Soot Particles ◽  
Surface Diameter

При сгорании топлива в судовом двигателе образуются частицы сажи, которые сорбируют в себе токсичные компоненты отработавших газов. Размеры этих частиц варьируются от 0,1 до 100 мкм. В области возможных диапазонов варьирования размеров частиц сажи актуальным является видимая и ближняя ИК-область электромагнитных волн. Решая обратную задачу ослабления и рассеяния света частицами можно получить информацию о концентрации и функции распределения частиц по размерам. Выполнен анализ возможности одновременной оценки концентрации и дисперсности лазерным методом дифференциального ослабления и описан вариант его технической реализации. Разработана четырех волновая лазерная система, которая позволяет измерять сигналы ослабления лазерного излучения методом дифференциального ослабления на трех длинах волн и сигнал рассеяния Ми на частицах аэрозоля излучения четвертого лазера. По измеренным сигналам ослабления рассчитан средний объемно-поверхностный диаметр аэрозольных частиц. Измерены сигналы ослабления лазерного излучения на трех длинах волн на разработанной лазерной установке в составе экспериментального стенда, что позволяет рассчитать значения массовой концентрации и среднего объемно-поверхностного диаметра аэрозольных частиц. Показано, что в зависимости от диапазона размеров частиц сажи выбираются соответствующие длины волн лазерного зондирования. Применение метода дифференциального ослабления лазерного излучения частицами сажи в выбросах судовых энергетических установок на нескольких длинах волн позволяет оценивать одновременно их концентрацию и характеристики дисперсности. When fuel is burned in a marine engine, soot particles are formed that absorb the toxic components of the exhaust gases. The sizes of these particles range from 0.1 to 100 microns. In the range of possible ranges of variation in the size of soot particles, the visible and near-IR regions of electromagnetic waves are relevant. By solving the inverse problem of attenuation and scattering of light by particles, one can obtain information about the concentration and distribution function of particles by size. The analysis of the possibility of simultaneous assessment of the concentration and dispersion by the laser method of differential attenuation is performed and a variant of its technical implementation is described. A four-wave laser system has been developed, which makes it possible to measure the attenuation signals of laser radiation by the differential attenuation method at three wavelengths and the Mie scattering signal on aerosol particles of the radiation of the fourth laser. The measured attenuation signals were used to calculate the average volumetric surface diameter of aerosol particles. The signals of the attenuation of laser radiation at three wavelengths were measured on a developed laser setup as part of an experimental stand, which makes it possible to calculate the values of the mass concentration and the average volume-surface diameter of aerosol particles. It is shown that, depending on the range of size of soot particles, the corresponding laser sounding wavelengths are chosen. The application of the method of differential attenuation of laser radiation by soot particles in the emissions of ship power plants at several wavelengths allows one to evaluate simultaneously their concentration and dispersion characteristics.

Influence of Collecting Substrates on the Characterization of Hygroscopic Properties of Inorganic Aerosol Particles

2014 ◽  
Vol 86 (5) ◽  
pp. 2648-2656 ◽  
Author(s):  
Hyo-Jin Eom ◽  
Dhrubajyoti Gupta ◽  
Xue Li ◽  
Hae-Jin Jung ◽  
HyeKyeong Kim ◽  
...  
Keyword(s):  
Aerosol Particles ◽  
Hygroscopic Properties ◽  
Inorganic Aerosol

scholarly journals Condensed-phase biogenic–anthropogenic interactions with implications for cold cloud formation

2017 ◽  
Vol 200 ◽  
pp. 165-194 ◽  
Author(s):  
Joseph C. Charnawskas ◽  
Peter A. Alpert ◽  
Andrew T. Lambe ◽  
Thomas Berkemeier ◽  
Rachel E. O’Brien ◽  
...  
Keyword(s):  
Freezing Temperature ◽  
Organic Aerosol ◽  
Ice Nucleation ◽  
Mixed Phase ◽  
Cloud Formation ◽  
Fossil Fuel Combustion ◽  
Soot Particles ◽  
Ice Nuclei ◽  
Deliquescence Relative Humidity ◽  
Homogeneous Freezing

Anthropogenic and biogenic gas emissions contribute to the formation of secondary organic aerosol (SOA). When present, soot particles from fossil fuel combustion can acquire a coating of SOA. We investigate SOA–soot biogenic–anthropogenic interactions and their impact on ice nucleation in relation to the particles’ organic phase state. SOA particles were generated from the OH oxidation of naphthalene, α-pinene, longifolene, or isoprene, with or without the presence of sulfate or soot particles. Corresponding particle glass transition (Tg) and full deliquescence relative humidity (FDRH) were estimated using a numerical diffusion model. Longifolene SOA particles are solid-like and all biogenic SOA sulfate mixtures exhibit a core–shell configuration (i.e.a sulfate-rich core coated with SOA). Biogenic SOA with or without sulfate formed ice at conditions expected for homogeneous ice nucleation, in agreement with respectiveTgand FDRH. α-pinene SOA coated soot particles nucleated ice above the homogeneous freezing temperature with soot acting as ice nuclei (IN). At lower temperatures the α-pinene SOA coating can be semisolid, inducing ice nucleation. Naphthalene SOA coated soot particles acted as ice nuclei above and below the homogeneous freezing limit, which can be explained by the presence of a highly viscous SOA phase. Our results suggest that biogenic SOA does not play a significant role in mixed-phase cloud formation and the presence of sulfate renders this even less likely. However, anthropogenic SOA may have an enhancing effect on cloud glaciation under mixed-phase and cirrus cloud conditions compared to biogenic SOA that dominate during pre-industrial times or in pristine areas.

scholarly journals Air Temperature and Anthropogenic Forcing: Insights from the Solid Earth

2011 ◽  
Vol 24 (2) ◽  
pp. 569-574 ◽  
Author(s):  
Jean O. Dickey ◽  
Steven L. Marcus ◽  
Olivier de Viron
Keyword(s):  
Air Temperature ◽  
Decadal Variability ◽  
Surface Air Temperature ◽  
Radiation Budget ◽  
Cloud Formation ◽  
Length Of Day ◽  
Anthropogenic Forcing ◽  
The Core ◽  
Earth’S Radiation Budget ◽  
Gas Effect

Abstract Earth’s rotation rate [i.e., length of day (LOD)], the angular momentum of the core (CAM), and surface air temperature (SAT) all have decadal variability. Previous investigators have found that the LOD fluctuations are largely attributed to core–mantle interactions and that the SAT is strongly anticorrelated with the decadal LOD. It is shown here that 1) the correlation among these three quantities exists until 1930, at which time anthropogenic forcing becomes highly significant; 2) correcting for anthropogenic effects, the correlation is present for the full span with a broadband variability centered at 78 yr; and 3) this result underscores the reality of anthropogenic temperature change, its size, and its temporal growth. The cause of this common variability needs to be further investigated and studied. Since temperature cannot affect the CAM or LOD to a sufficient extent, the results favor either a direct effect of Earth’s core-generated magnetic field (e.g., through the modulation of charged-particle fluxes, which may impact cloud formation) or a more indirect effect of some other core process on the climate—or yet another process that affects both. In all three cases, their signals would be much smaller than the anthropogenic greenhouse gas effect on Earth’s radiation budget during the coming century.

scholarly journals Hygroscopic properties of ultrafine aerosol particles in the boreal forest: diurnal variation, solubility and the influence of sulfuric acid

2007 ◽  
Vol 7 (1) ◽  
pp. 211-222 ◽  
Author(s):  
M. Ehn ◽  
T. Petäjä ◽  
H. Aufmhoff ◽  
P. Aalto ◽  
K. Hämeri ◽  
...  
Keyword(s):  
Sulfuric Acid ◽  
Boreal Forest ◽  
Diurnal Variation ◽  
Gas Phase ◽  
Aerosol Particles ◽  
Particle Formation ◽  
Time Of Day ◽  
New Particle Formation ◽  
Hygroscopic Growth ◽  
Hygroscopic Properties

Abstract. The hygroscopic growth of aerosol particles present in a boreal forest was measured at a relative humidity of 88%. Simultaneously the gas phase concentration of sulfuric acid, a very hygroscopic compound, was monitored. The focus was mainly on days with new particle formation by nucleation. The measured hygroscopic growth factors (GF) correlated positively with the gaseous phase sulfuric acid concentrations. The smaller the particles, the stronger the correlation, with r=0.20 for 50 nm and r=0.50 for 10 nm particles. The increase in GF due to condensing sulfuric acid is expected to be larger for particles with initially smaller masses. During new particle formation, the changes in solubility of the new particles were calculated during their growth to Aitken mode sizes. As the modal diameter increased, the solubility of the particles decreased. This indicated that the initial particle growth was due to more hygroscopic compounds, whereas the later growth during the evening and night was mainly caused by less hygroscopic or even hydrophobic compounds. For all the measured sizes, a diurnal variation in GF was observed both during days with and without particle formation. The GF was lowest at around midnight, with a mean value of 1.12–1.24 depending on particle size and if new particle formation occurred during the day, and increased to 1.25–1.34 around noon. This can be tentatively explained by day- and nighttime gas-phase chemistry; different vapors will be present depending on the time of day, and through condensation these compounds will alter the hygroscopic properties of the particles in different ways.

scholarly journals A simplified empirical method for determination of aerosol hygroscopicity and composition

2010 ◽  
Vol 10 (10) ◽  
pp. 23627-23656
Author(s):  
C. H. Chan ◽  
A. Y. S. Cheng ◽  
A. Viseu
Keyword(s):  
Atmospheric Aerosols ◽  
Climate Model ◽  
Empirical Method ◽  
Radiation Budget ◽  
Cloud Formation ◽  
Monthly Variation ◽  
Aerosol Composition ◽  
Remote System ◽  
Aerosol Hygroscopicity

Abstract. Atmospheric aerosols have substantial influence on the Earth's radiation budget, visibility, cloud formation and precipitation. The aerosol hygroscopicity and the composition of aerosols are of vital importance for solar radiation budget calculation, cloud formation mechanism, and measurement of aerosol spatiotemporal distribution through remote sensing, such as Lidar, MODIS and sun/star photometer. In this paper, hourly averaged records of humidity, visibility and aerosol concentration, conducted in Macao, P.R.C. from 1 February 2006 to 31 December 2008 (LT), are used to estimate aerosol hygroscopicity and composition with a simplified empirical method. The result of monthly variation of aerosol hygroscopicity indicates the important role of aerosol composition on optical properties, which is in agreement with the previous study. This aerosol composition pattern is also consistent with the Asiatic Monsoon pattern and vicinity, such as Hong Kong. The monthly variation of aerosol hygroscopicity and composition also shows the necessity to consider such a factor for the aerosols monitoring by remote system and aerosols forcing simulated by climate model.

Experimental evidence for the role of ions in particle nucleation under atmospheric conditions

2006 ◽  
Vol 463 (2078) ◽  
pp. 385-396 ◽  
Author(s):  
Henrik Svensmark ◽  
Jens Olaf P Pedersen ◽  
Nigel D Marsh ◽  
Martin B Enghoff ◽  
Ulrik I Uggerhøj
Keyword(s):  
Sulphur Dioxide ◽  
Aerosol Particles ◽  
Experimental Studies ◽  
Negative Ion ◽  
Cloud Formation ◽  
Particle Nucleation ◽  
Atmospheric Conditions ◽  
Ion Density ◽  
Stable Clusters

Experimental studies of aerosol nucleation in air, containing trace amounts of ozone, sulphur dioxide and water vapour at concentrations relevant for the Earth's atmosphere, are reported. The production of new aerosol particles is found to be proportional to the negative ion density and yields nucleation rates of the order of 0.1–1 cm −3  s −1 . This suggests that the ions are active in generating an atmospheric reservoir of small thermodynamically stable clusters, which are important for nucleation processes in the atmosphere and ultimately for cloud formation.

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