SARS: A Better Breathing Mask
In The Age Of Sars, Make a Better Breathing Mask and the World Will Beat a Path to Your Door
St. Louis, Mo., May/June 2003: In the age of SARS, what the world needs is a better respirator, or breathing mask. As hospitals worldwide face major shortages of masks, Da-Ren Chen, Ph.D., assistant professor of mechanical engineering at Washington University in St. Louis, has developed material for a breathing mask, creating a polymer recipe of nanofibers so tiny and skinny that the entry of harmful particles as minute as viruses and bacteria is nearly impossible.
The mask is comprised of just less than two percent material, more than 98 percent air. Thus, it is inexpensive to mass-produce, allowing companies a good profit opportunity. Because it is constructed of such tiny nanofibers, it is far more comfortable to wear than commercial masks.
"What we've done is to improve the particle collection ability while reducing the pressure drop that occurs when air molecules hit the mask fiber surface, which is what makes people uncomfortable," said Chen, a member of Washington University's Environmental Engineering Science Program.
Ninety percent of respirators or masks made today are made of glass fibers, which are under fire by some critics as posing health problems. Chen's material is a synthetic polymer. Current masks or respirators are made of fibers as small as 500 nanometers, but Chen's are made in the 20 to 30-nanometer range.
The tiny size of the fiber material is important because bacteria are actually in the micrometer size range. One micrometer is one-millionth of a meter (a meter is approximately one yard); one nanometer is approximately one-billionth of a yard. A nanometer is one-thousandth of a micrometer; in comparison, a strand of human hair is typically 50 to 100 micrometers thick.
Yet, viruses are even smaller creatures, most of them are in the nanometer size range. Thus, Chen is shooting for material in the 20-nanometer range.
Da Ren Chen is a mechanical engineer engaged in research in the field of particle measurement and instrumentation, particle filtration and separation, aerosol dynamics modeling, aerosol science and technology. Chen received his B.S. from the National Tsing Hua University in Hsinchu, Taiwan, ROC, and a doctorate from the University of Minnesota.
Chen's innovative, possibly revolutionary, synthetic polymer is remarkable, both for its technical performance and price performance characteristics. Even users who don't "need" face masks made from Chen's new material, might purchase them strictly on the basis of cost savings. Ironically the very same physical characteristics that make Chen's nanofiber so great technically, also reduce material costs to almost nothing. As the report notes:
"The mask is comprised of just less than two percent material, more than 98 percent air. Thus, it is inexpensive to mass-produce, allowing companies a good profit opportunity. Because it is constructed of such tiny nanofibers, it is far more comfortable to wear than commercial masks."
A face mask that filters out harmful matter more thoroughly, yet feels less suffocating than its competitors, precisely because it is over 98% air. Now if that doesn't qualify as intelligent product design, not to mention good business sense, I don't know what does.
-- Bevin Chu
Explanation: In The Age Of Sars, Make a Better Breathing Mask and the World Will Beat a Path to Your Door
Illustration(s): Da Ren Chen, Ph.D.
Author(s): Robert Batterson
Affiliation: Washington University in St. Louis
Publication Date: May/June 2003
Original Language: English
Editor: Bevin Chu, Registered Architect