Monday, June 4, 2012



essay number 1

   ABDULLA MOHAMED ALSAADI

H00210201
AIR FILTRATION

Introduction
Air filtration in the UAE. Studies show that contaminants that are in the indoor air that you breathe can cause short and long term health problems over a period of time. Main contaminants that are involved in indoor air are bioaerosols which include pathogens and allergens, etc.
Some of the health effects range from acute effects such as allergic reactions to chronic effects such as lung cancer. All of these effects can be prevented with the help of an air purifier.
Early history
Air filtration was first discovered by John and Charles Dean in 1823 when they patented their new smoke-protecting device. It allowed for firefighters to be protected from the acrid smoke and dangerous chemicals in the air when they fought fires. Later, that device was adapted for use by underwater divers.
Around the same time, a man named Augustus Siebe was marketing his own version of a diving respirator, which comprised of a helmet and a series of small tubes. A tube on one side of the helmet pumped fresh air in, while a tube on the other side allowed bad air to escape.
Mr. Siebe later went on to found Siebe, Gorman, and Co., a company that would be instrumental in developing gas masks for the war effort in 1914.
In 1849 Lewis Haslett get patent  with a great idea. he called an “Inhaler or Lung Protector”. (Haslett. 2007). His new device was an improvement on the old air breathing devices because it contained a special filter used to get rid of dust.
Development
"A system is described for the collection of volatiles produced by plants and insects that minimizes stresses on the plant or insect in an environment that is free from chemical impurities. Air entering a volatile collection chamber containing insects and/or plants was purified using a nonwoven fabric medium infused with charcoal"( Heath . 1992) .When three layers of this material were used, the total amount of impurities detected by gas chromatography was less than 40 ng/hr at a collection rate of 1 L/min. The air filtration system can maintain this level of air purification for 96 hr at an air flow of 0.43 m/sec, or a total volume of approximately 750,000 L of air. The air filtration system did not alter the relative humidity of the purified air compared to the relative humidity of ambient air. A multiport collector system was developed for use with the insect volatile collection system and enabled up to three samples to be collected without disturbing the system.

Modern developments
Models and theories of airflow are described, and this description is followed by an account of the various mechanisms of particle capture by mechanical means and by electric forces. Electrically charged materials that are, or could be, used in respirator filters are described and classified according to the methods by which they become charged. Ways of measuring the charge level are summarized, and the stability of electric charge on filters is discussed with respect to storage, exposure to harsh environmental conditions and use. Measurements of filtration efficiency using monodisperse laboratory aerosols, industrial aerosols and standard aerosols are put into their various perspectives. The review ends with a brief account of the place of coarse mechanical filters in industrial hygiene.
 Air filter elements of various types are used for filtering the intake air.  MAHLE has meanwhile introduced new developments aimed at achieving higher efficiency and dust holding capacities. To this end, multi-layer filter materials made from cellulose, melt blown and nanofibers as well as completely synthetic non-woven materials have already been optimized for mass production.


Conclusion
In conclusion, there are many resources to air pollution that cause health risks. However, there are several ways for air filtration to live in a healthy life full of fresh air, but we have to cooperate to keep the air clean from contaminated material.



References

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