Put on a purple filtered respirator.
http://www.osha.gov/pls/oshaweb/owadisp.show_document?p_id=12716&p_table=standards
Never give a respirator to anyone without training...you are opening yourself up to more lawsuits...
From OSHA
In any workplace where respirators are necessary to protect the health of the employee or whenever respirators are required by the employer, the employer shall establish and implement a written respiratory protection program with worksite-specific procedures. The program shall be updated as necessary to reflect those changes in workplace conditions that affect respirator use. The employer shall include in the program the following provisions of this section, as applicable:
1910.134(c)(1)(i)Procedures for selecting respirators for use in the workplace;
1910.134(c)(1)(ii)Medical evaluations of employees required to use respirators;
1910.134(c)(1)(iii)Fit testing procedures for tight-fitting respirators;
1910.134(c)(1)(iv)Procedures for proper use of respirators in routine and reasonably foreseeable emergency situations;
1910.134(c)(1)(v)Procedures and schedules for cleaning, disinfecting, storing, inspecting, repairing, discarding, and otherwise maintaining respirators;
1910.134(c)(1)(vi)Procedures to ensure adequate air quality, quantity, and flow of breathing air for atmosphere-supplying respirators;
1910.134(c)(1)(vii)Training of employees in the respiratory hazards to which they are potentially exposed during routine and emergency situations;
1910.134(c)(1)(viii)Training of employees in the proper use of respirators, including putting on and removing them, any limitations on their use, and their maintenance; and
1910.134(c)(1)(ix)Procedures for regularly evaluating the effectiveness of the program.
1910.134(c)(2)