Table 3.

Measured personal NO and NO₂ exposure levels (ppm) for underground, mixed, and surface workers by mining facility: full-shift time-weighted average concentrations

Mining facilitya	NO measurements					NO2 measurements
	n	n < LOD	AM	GM	GSD	n	n < LOD	AM	GM	GSD
Underground
A	105	0	1.07	1.00	1.5	108	0	0.60	0.52	1.8
B	117	1	1.49	0.83	4.4	120	10	0.22	0.12	3.8
E	109	1	1.11	0.64	3.6	115	2	0.28	0.20	2.6
G	127	11	0.20	0.11	3.6	127	8	0.10	0.05	3.6
H	118	3	0.68	0.47	2.9	118	1	0.13	0.09	2.4
I	90	1	0.57	0.40	2.7	101	3	0.18	0.13	2.5
Mixed underground and surfaceb
A	30	1	0.5	0.29	3.8	30	0	0.28	0.12	4.8
B	4	0	0.37	0.29	2.2	4	0	0.06	0.05	1.6
E	11	4	0.07	0.03	4.4	11	3	0.07	0.04	3.4
G	18	5	0.05	0.02	3.3	18	1	0.04	0.03	2.7
H	16	2	0.33	0.07	6.9	16	1	0.07	0.03	3.7
I	15	4	0.16	0.06	5.1	18	5	0.07	0.03	3.4
Surface
A	34	9	0.11	0.04	4.5	34	0	0.01	0.01	2.0
B	61	1	0.09	0.05	2.6	61	19	0.02	0.02	2.0
E	24	15	0.03	0.01	3.1	26	3	0.05	0.03	2.3
G	31	15	0.02	0.01	2.4	31	7	0.02	0.01	2.4
H	33	8	0.04	0.03	2.8	33	1	0.04	0.03	2.2
I	42	20	0.09	0.03	4.5	48	14	0.06	0.03	3.1

n, Number of measurements.

^aNo NO or NO₂ measurements were taken at Facility D due to technical problems with the sampling method prior to the survey.

^bMixed workers spent time both underground and on the surface during the work shift monitored.