National Survey of Workplaces Handling and Manufacturing Nanomaterials, Exposure to and Health Effects of Nanomaterials, and Evaluation of Nanomaterial Safety Data Sheets

Table 3

Results of workplace air measurements (unit: numeric, %).

	Total	TiO2	SiO2	Al2O3	Ag	ZnO	Fe	Others
Number of companies: conducted workplace air measurements	136; (100)	40; (100)	32; (100)	17; (100)	13; (100)	13; (100)	6; (100)	15; (100)
Number of companies: nondetected	34; (25.0)	17; (42.5)	4; (12.5)	2; (11.8)	5; (38.5)	1; (7.7)	2; (33.3)	3; (20.0)
Number of companies: detected	29; (21.3)	1; (2.5)	8; (25.0)	7; (41.2)	0; (0.0)	9; (69.2)	2; (33.3)	2; (13.3)
Lowest level (mg/m^3)	—	0.0001	0.009	0.005		0.001	0.008	0.013
Highest level (mg/m^3)	—	0.001	3.72	9.17		0.70	1.16	0.02
OEL (mg/m^3)	—	10	10; 0.05	10	0.1	2	1	—
Number of companies: no data for materials	73; (53.7)	22; (55.0)	20; (62.5)	8; (47.0)	8; (61.5)	3; (23.1)	2; (33.3)	10; (66.7)

Diatomaceous earth; silica, crystalline quartz; respirable fraction; iron salts; OEL: occupational exposure limit.