China tightens quality control on face masks after foreign complaints

An inspector of Guangdong Medical Devices Quality Surveillance and Test Institute tests the quality of a face mask in Guangzhou, south China's Guangdong Province, April 2, 2020. (Xinhua/Li Jiale)

GUANGZHOU, April 6 (Xinhua) -- One of Tang Zhi's jobs is to count from 1 to 100 loudly and slowly, a monotonous but critical procedure to test the quality of a surgical mask.

Walking into a test room and putting on a hanging N95 mask that is connected to a sampling tube, the quality inspector stands quietly, breathing normally at first, then deeply, before turning his head left and right, and up and down. Finally, Tang counts the numbers out loud and returns to his normal breath.