Table 1.
Descriptive statistics of underground area air measurements for DE components in seven non-metal mining facilities
| DE component | n | % <LOD | AM | GM | GSD | GSDbf | GSDwf | 10th percentile | 90th percentile |
| EC measurements (μg m−3) | |||||||||
| TEC | 177 | 9 | 171 | 66 | 5.2 | 2.7 | 3.8 | 5 | 450 |
| REC | 176 | 7 | 159 | 66 | 4.7 | 2.6 | 3.4 | 8 | 443 |
| SEC | 163 | 16 | 115 | 44 | 5.2 | 2.8 | 3.9 | 3 | 281 |
| OC measurements (μg m−3) | |||||||||
| TOC | 177 | 2 | 150 | 125 | 1.9 | 1.2 | 1.9 | 57 | 274 |
| ROC | 177 | 2 | 92 | 78 | 1.8 | 1.3 | 1.8 | 38 | 165 |
| SOC | 166 | 1 | 109 | 90 | 2.0 | 1.5 | 1.8 | 37 | 187 |
| Gaseous measurements (ppm) | |||||||||
| NO | 179 | 10 | 1.48 | 0.67 | 4.8 | 2.2 | 4.0 | 0.04 | 3.57 |
| NO2 | 179 | 41 | 0.50 | 0.11 | 7.5 | 5.1 | 3.8 | 0.01 | 1.32 |
| CO | 171 | 15 | 2.87 | 1.52 | 3.7 | 2.0 | 3.2 | 0.20 | 6.23 |
| CO2 | 164 | 0 | 794 | 736 | 1.5 | 1.4 | 1.3 | 502 | 1274 |
| Particulate measurements (mg m−3) | |||||||||
| TD | 178 | 1 | 3.37 | 1.41 | 3.9 | 1.4 | 3.7 | 0.29 | 6.58 |
| RD | 172 | 2 | 0.89 | 0.47 | 3.2 | 1.8 | 2.8 | 0.12 | 2.12 |
| SMDa | 93 | 5 | 0.32 | 0.18 | 4.6 | 2.0 | 4.2 | 0.06 | 0.60 |
| SCD | 164 | 27 | 0.17 | 0.04 | 7.7 | 2.0 | 6.9 | 0.002 | 0.35 |
n = number of measurements; % <LOD = percentage of measurements below the LOD; AM = arithmetic mean; GM = geometric mean; GSDbf = geometric standard deviation of the between-facility distribution of air concentrations; GSDwf = geometric standard deviation of the within-facility distribution of air concentrations; 10th percentile = 10th percentile of the exposure distribution; 90th percentile = 90th percentile of the exposure distribution.
a
For three facilities the SMD filters were not re-weighed before the SCD analysis and therefore SMD is missing for Facilities D, G, and I.