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Table 2 Descriptive statistics for carbon nanotube or nanofiber (CNT/F) exposure variables among 108 study participants

From: Association of pulmonary, cardiovascular, and hematologic metrics with carbon nanotube and nanofiber exposure among U.S. workers: a cross-sectional study

Exposure Variablea

Mean

Median

Standard deviation

25th, 75th %-ile

Multi-day mean EC (background-corrected) concentration (μg/m 3 )

 Respirable size fraction

1.00

0.096

4.94

0.018, 0.33

 Inhalable size fraction

6.22

0.24

41.2

0.027, 1.32

Multi-day mean TEM structure count concentration (structures/cm 3 )

 All CNT/F-containing structures

0.128

7.29E-3

0.469

9.02E-4, 8.30E-2

 Structures < 10 μm diameter

0.121

6.03E-3

0.440

3.80E-4, 8.34E-2

 Structures <5 μm diameter

0.0865

3.04E-3

0.316

9.60E-5, 6.52E-2

 Structures <2 μm diameter

0.0443

3.08E-4

0.201

0, 3.33E-3

 Structures <1 μm diameter

0.0398

0

0.194

0, 7.12E-4

 Single fiber structures

0.0324

0

0.193

0, 0

Duration worked with CNT/F (years)

4.07

3.66

4.01

1.05, 5.61

  1. aAbbreviations: CNT/F carbon nanotubes or nanofibers, EC elemental carbon, TEM transmission electron microscopy