---
kind: "section"
citation: "10 C.F.R. § 835.209"
title: "10"
number: "835.209"
heading: "Concentrations of radioactive material in air."
url: "https://uscodex.org/cfr/10/835.209"
---

# §835.209. Concentrations of radioactive material in air.

- (a) The derived air concentration (DAC) values given in appendices A and C of this part shall be used in the control of occupational exposures to airborne radioactive material.
- (b) The estimation of internal dose shall be based on bioassay data rather than air concentration values unless bioassay data are:
  - (1) Unavailable;
  - (2) Inadequate; or
  - (3) **Internal dose estimates based on air concentration values are demonstrated to be as or more accurate.**

## Notes

### Amendments

[58 FR 65485, Dec. 14, 1993, as amended at 63 FR 59682, Nov. 4, 1998]

### Authority

Authority: 42 U.S.C. 2201, 7191; 50 U.S.C. 2410.

### Source

Source: 58 FR 65485, Dec. 14, 1993, unless otherwise noted.

### Amendments

[58 FR 65485, Dec. 14, 1993, as amended at 63 FR 59682, Nov. 4, 1998]