Zhang was inspired by an American PhD student, Thomas Talhelm, who put directions on his website on how to make an air purifier with only 166 yuan ($27).  Talhelm, the 28-year-old American who inspired Zhang, did not come to China to work on air filters. As a PhD student in psychology at the University of Virginia, Talhelm was in China on a Fulbright scholarship researching cultural differences between northern and southern China. But when the air in Beijing took a turn for the worse in January 2013, it set him on a path that ended with him telling the world about a simple DIY solution fo...