Working Level Month
The term Working Level Month (WLM) is a unit of measurement from occupational medicine .
Emergence
It was introduced in the 1950s specifically for occupational safety in uranium mines in the USA in order to record radiation exposure resulting from radioactive pollution, radon and its decay products in the air we breathe.
definition
If a working level (WL, 1.30 · 10 5 MeV / l or 2.08 · 10 −5 J / m³) affects a person for 170 hours (monthly workload), one speaks of a working level month .
The unit relates to any combination of activity concentrations of short-lived radon progeny in 1 liter of air, which lead to the emission of 1 WL = 1.30 · 10 5 MeV potential alpha energy in the event of radioactive decay.
Medical importance
Above a certain level, radioactivity in the breathing air has a carcinogenic effect, especially in the lungs, i.e. it causes cancer. Different types of tumors are influenced in different ways. As it quantifies radiation exposure, the unit makes it possible to minimize the risk of cancer and to assess its specific influence on the various forms of lung cancer .
Individual evidence
- ↑ a b c Technical Report: The German Uranium Miners Cohort Study (Wismut cohort), 1946 - 2003 Federal Office for Radiation Protection, 2011 ( online here )
- ↑ a b c d D. Taeger, B. Pesch, G. Johnen, T. Wiethege, T. Brüning: Investigations at the Wismut Section Archive: Influence of ionizing radiation and quartz dust on the development of lung carcinomas . BGFA-Info 03/05 online here