As to the collaboration, the managers were asked by the team of researchers after occupational health education to continue supporting the workers to use personal protective equipment at both the assembly section and other sections. The managers permitted the workers to join in all steps of this research. The workers willingly participated in this research and collaborated with managers on that. However, they were not obligated to use the mask (3M, 9322). They could change the mask, if they found its decreased efficacy or its defect.