A Cohort Study on Self-Reported Respiratory Symptoms of Toner-Handling Workers: Cross-Sectional and Longitudinal Analysis from 2003 to 2008

Table 1

Personal exposure measurement.

Toner-handling work category	1st survey	2nd survey	3rd survey	4th survey	5th survey	6th survey
Toner development
Sampling case^#	19	17	11	11	5	7
GM^## (mg/m^3)	0.026	0.026	0.014	0.012	0.015	0.011
(GSD^##)	(1.974)	(2.059)	(1.507)	(1.355)	(1.069)	(1.299)
Median (mg/m^3)	0.018	0.020	0.014	0.013	0.015	0.011
(quartile 1, quartile 3)	(0.015, 0.039)	(0.015, 0.041)	(0.010, 0.016)	(0.011, 0.015)	(0.014, 0.015)	(0.009, 0.016)
Toner manufacturing
Sampling case	61	65	72	60	74	71
GM (mg/m^3)	0.075	0.064	0.036	0.043	0.028	0.025
(GSD)	(3.446)	(3.742)	(2.963)	(3.447)	(2.847)	(2.909)
Median (mg/m^3)	0.045	0.044	0.035	0.023	0.018	0.016
(quartile 1, quartile 3)	(0.032, 0.159)	(0.021, 0.156)	(0.014, 0.065)	(0.017, 0.106)	(0.014, 0.047)	(0.013, 0.034)
Photocopier development
Sampling case	10	12	13	11	9	6
GM (mg/m^3)	0.018	0.016	0.014	0.014	0.014	0.016
(GSD)	(1.303)	(1.107)	(2.210)	(1.326)	(1.432)	(1.038)
Median (mg/m^3)	0.017	0.016	0.011	0.015	0.015	0.016
(quartile 1, quartile 3)	(0.016, 0.020)	(0.014, 0.018)	(0.009, 0.017)	(0.011, 0.016)	(0.010, 0.019)	(0.015, 0.016)
Toner and photocopier recycling
Sampling case	23	29	33	34	50	44
GM (mg/m^3)	0.569	0.236	0.075	0.066	0.067	0.029
(GSD)	(3.704)	(2.562)	(3.169)	(2.879)	(2.908)	(2.638)
Median (mg/m^3)	1.054	0.211	0.060	0.051	0.065	0.021
(quartile 1, quartile 3)	(0.1 10, 1.420)	(0.139, 0.363)	(0.036, 0.137)	(0.037, 0.151)	(0.030, 0.126)	(0.014, 0.050)
Customer service
Sampling case	18	22	23	18	16	19
GM (mg/m^3)	0.020	0.018	0.013	0.013	0.013	0.013
(GSD)	(1.308)	(1.635)	(1.370)	(1.419)	(1.391)	(1.471)
Median (mg/m^3)	0.019	0.016	0.013	0.015	0.014	0.014
(quartile 1, quartile 3)	(0.016, 0.022)	(0.015, 0.019)	(0.010, 0.016)	(0.009, 0.016)	(0.009, 0.017)	(0.009, 0.016)

#Sampling case: about 5 workers in one workplace were randomly selected and conducted personal exposure measurement.
For toner manufacturing process and toner and photocopier recycling process, the workplaces were subdivided and the sampling cases increased.
On the other hand, toner development process, photocopier development process, and customer service process had a few work units.
##GM: geometric mean. GSD: geomrtric standard deviation.