Table 3 HDI monomer and oligomer concentrations by task in five vocational schools

Sampling site	HDI type	No of personal samples	Concentration (μg/m³)		LOD (%)
Sampling site	HDI type	No of personal samples	Median	Maximum	LOD (%)
Spraying
	Monomer	29	0.001	0.006	41.4
	Oligomer	29	0.283	0.916	27.9
Mixing
	Monomer	13	0.0003	0.0003	92.3
	Oligomer	13	0.4365	0.6890	69.2
Brush cleaning
	Monomer	5	–	–	100
	Oligomer	5	0.079	0.079	80

HDI, hexamethylene diisocyanate; LOD (%), percentage of samples below the detection limit.