Table 2.

Effect of tasks on personal level of exposure to respirable indium (μg m⁻³)

Model with tasks	N	Average time spent performing task, per shiftb (min–max)	β a	e	P	%time observed in N95	%time observed in full-face or PAPR
Intercept	159	–	1.76	0.15	<0.0001	–	–
Sanding	9	87 (25–172)	0.027	0.004	< 0.0001	10.0	55.8
Powder transfer, reclaim	9	116 (30–224)	0.016	0.003	< 0.0001	0	84.3
Package	8	80 (15–319)	−0.006	0.003	0.09	17.2	0
Powder transfer, refinery	6	58 (10–122)	0.016	0.008	0.05	24.8	5.5
Handling indium materials	10	43 (5–95)	0.014	0.008	0.07	0	7.0
Liquid transfer, ITO	17	56 (5–135)	0.014	0.005	0.02	0	15.6
		Random effects model	Mixed model			% variance explained
σ 2 ww		1.38	0.98			30.0
σ 2 bw		1.32	0.74			43.9
σ 2 total		2.70	1.72			36.3

N, number of observations; β, regression coefficient for ln-transformed exposure data; e, standard, error; P, P value; %time, percent time.

^aPer 1 min of task performance.

^bAverage time in minutes.