نتایج جستجو برای: particles and aerosols
تعداد نتایج: 16853764 فیلتر نتایج به سال:
BACKGROUND The potential for human influenza viruses to spread through fine particle aerosols remains controversial. The objective of our study was to determine whether influenza viruses could be detected in fine particles in hospital rooms. METHODS AND FINDINGS We sampled the air in 2-bed patient isolation rooms for four hours, placing cyclone samplers at heights of 1.5m and 1.0m. We collect...
Aerosol optical depth and Ångström exponent were obtained from multi filter rotating shadowband radiometer (MFRSR) observations carried out at the island of Lampedusa, in the Central Mediterranean, in the period July 2001–September 2003. The average aerosol optical depth at 495.7 nm, τ , is 0.24±0.14; the average Ångström exponent, α, is 0.86±0.63. The observed values of τ range from 0.03 to 1....
In the standard of the approval test for dust respirator certification, test aerosols are defined as air containing quartz particles of 2 microns or smaller1. However, it is well-known that the filtration efficiency of air filters depends on the size of the test aerosol particles. Alternative test aerosols containing submicron size particles will be studied for use in future approval test of du...
Treatment of pulmonary and systemic diseases may be improved and toxicity reduced by pulmonary deposition of drug-containing aerosols exhibiting delayed dissolution. Aqueous disodium fluorescein and pentamidine aerosols were dried, concentrated, and condensation coated with paraffin wax. The apparent mass median aerodynamic diameters of the coated fluorescein particles were 2.8-4.0 microns. Wax...
Chemical Characterization of Fine and Coarse Particles in Gosan, Korea during Springtime Dust Events
Particulate matter was collected at Gosan, Korea, a remote location in the East China Sea, from late-March through May, 2007. Two sizes of particles, fine (PM2.5) and coarse (PM10–2.5) modes, were analyzed for chemical composition. Samples were analyzed by mass, elemental and organic carbon, and inorganic ions. Organic molecular markers were also measured using solvent-extraction gas chromatogr...
The heterogeneous conversion of NO2 on different secondary organic aerosols (SOA) was investigated with the focus on a possible formation of nitrous acid (HONO). In one set of experiments different organic aerosols were produced in the reactions of O3 with α-pinene, limonene or catechol and OH radicals with toluene or limonene, respectively. The aerosols were sampled on filters and exposed to h...
The present review is the summary of an expert workshop that took place in Vence (France) in 2007 on the role of distal airways in asthma. The evidence showing inflammation and remodelling in distal airways, and their possible involvement in asthma control and natural history, was reviewed. The usefulness and limitations of various techniques used for assessing distal airways were also evaluate...
Electrostatic charging occurs in most aerosol generation processes and can significantly influence subsequent particle deposition rates and patterns in the respiratory tract through the image and space forces. The behavior of inhaled aerosols with charge is expected to be most affected in the upper airways, where particles come in close proximity to the narrow turbinate surface, and before char...
Introduction: The OMEGA instrument onboard Mars Express has obtained several nadir observations of the surface of Mars at the boundary between day and night (the “terminator”) since early 2004. Even under clear atmospheric conditions, the path length of photons in the aerosols layer is high for such observations. In the dayside, almost all solar photons heading toward the surface are stopped by...
Biological aerosols, typically identified through their fluorescence properties, strongly influence clouds and climate. Sea spray aerosol (SSA) particles are a major source of biological ...
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