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Why Tiny Particles Pose Big Problems - airborne dust causes health problems National Wildlife - Find Articles

A few years ago, if you had driven along certain residential streets in Long Beach or Los Angeles, you might have seen Ann Miguel pushing a vacuum cleaner down the center of the road. No, she's not an obsessive neatnik. A scientist at California Institute of Technology, Miguel is one of a growing number of researchers studying an environmental threat all around us: dust.

Dust is not just the collection of lint that drifts into the corners of your rooms. Tiny particles, often called particulate matter, are swept up by passing car tires, blown into the wind from construction sites and farms and spewed into the air by tail pipes and power plants. And experts say there is growing evidence that all this dust and soot may cause serious health problems-not only for humans but for other species as well.

Tiny airborne particles are a major cause of climate change

Tiny airborne particles are a major cause of climate change
The local effect of atmospheric aerosols can be greater than The Greenhouse Effect Rehovot, Israel -- July 17, 2006 - A scientist at the Weizmann Institute of Science and his colleagues caused a storm in the atmospheric community when they suggested a few years back that tiny airborne particles, known as aerosols, may be one of the main culprits causing climate change - having, on a local scale, an even greater impact than the greenhouse gases effect. Attempts to understand how these particles influence clouds have generated many uncertainties. A new paper by Dr. Ilan Koren of the Weizmann Institute Environmental Studies and Energy Research Department and Dr. Yoram Kauffman of the NASA/Goddard Space Flight Center, USA,* published in Science Express online, weaves together two opposing effects of atmospheric aerosols to provide a comprehensive picture of how they may be affecting our climate.

Airborne Particles: Information from Answers.com

A suspension of airborne particles, whether liquid droplets or solids, is generally referred to as an aerosol. As toxicants, airborne particles are more complex than pollutant gases and vapors because of the additional variables of particle size and mixed chemical composition. Size affects particle motion and the probabilities for physical phenomena such as coagulation, dispersion, sedimentation, and impaction onto surfaces. It is not possible to fully characterize a given particle by a single size parameter. For example, a particle's aerodynamic properties depend on density and shape as well as linear dimensions.

Typically, aerosols are composed of particles of many different sizes and are therefore called "heterodisperse" or "polydisperse." Different aerosols have different degrees of size dispersion. It is therefore necessary to specify at least two parameters in characterizing aerosol size: a measure of central tendency, such as a mean or median, and a measure of dispersion, such as a geometric standard deviation.