Aerosols influence climate by altering the global energy balance via scattering and absorbing solar radiation (direct effects), and by their effect on the reflectance of clouds and occurrence of precipitation (indirect effects). Aerosols also influence biogeochemical cycles, lead to diminished environmental visibility, and harm human health. This thesis focuses on advancing knowledge of critica...

This work gives sequence to the study on the measurement of the electrostatic charges in aerosols. The particle charge classifier developed for this purpose and presented in the previous paper (Marra and Coury, 2000) has been used here to measure the particle charge distribution of a number of different aerosols. The charges acquired by the particles were naturally derived from the aerosol gene...

OBJECTIVE. Specification of appropriate personal protective equipment for respiratory protection against influenza is somewhat controversial. In a clinical environment, N95 filtering facepiece respirators (FFRs) are often recommended for respiratory protection against infectious aerosols. This study evaluates the ability of N95 FFRs to capture viable H1N1 influenza aerosols. METHODs. Five N95 F...

Airborne mineral dust particles serve as cloud condensation nuclei (CCN), thereby influencing the formation and properties of warm clouds. It is therefore of atmospheric interest how dust aerosols with different mineralogy behave when exposed to high relative humidity (RH) or supersaturation (SS) with respect to liquid water. In this study the subsaturated hygroscopic growth and the supersatura...

BACKGROUND Air pollutants have not been associated with ambulatory electrocardiographic evidence of ST-segment depression ≥ 1 mm (probable cardiac ischemia). We previously found that markers of primary (combustion-related) organic aerosols and gases were positively associated with circulating biomarkers of inflammation and ambulatory blood pressure in the present cohort panel study of elderly s...

This is the second of series on the impact of dust. It focuses on the physical, chemical and physiological effects of dust particles and aerosols. Plants of all types and classes (from algae to forest trees and everything in between) are adversely affected either directly through abrasion by airborne particles or through interference with plant physiology or indirectly through the impact on soi...

Formation of cirrus clouds depends on the availability of ice nuclei to begin condensation of atmospheric water vapor. Although it is known that only a small fraction of atmospheric aerosols are efficient ice nuclei, the critical ingredients that make those aerosols so effective have not been established. We have determined in situ the composition of the residual particles within cirrus crystal...

the impacts of dust and sand storms (dss) on people, crops, livestock, infrastructure and health are well documented. data have accumulated on the deleterious effects of dust aerosols when they settle on plants. sand blasting of low growing plants is a common cause of failure in reforestation efforts. burial of plants by moving sands are also a cause of much damage. the physics of moving sand a...

The activation of aerosol particles into cloud droplets in the Earth's atmosphere is both a key process for the climate budget and a main source of uncertainty. Its investigation is facing major experimental challenges, as no technique can measure the main driving parameters, the Raoult's term and surface tension, σ, for sub-micron atmospheric particles. In addition, the surfactant fraction of ...

[1] One proposed side effect of geoengineering with stratospheric sulfate aerosols is sky whitening during the day and afterglows near sunset, as is seen after large volcanic eruptions. Sulfate aerosols in the stratosphere would increase diffuse light received at the surface, but with a non-uniform spectral distribution. We use a radiative transfer model to calculate spectral irradiance for ide...