Working Level (WL) 2
Working Level (WL) 2 :
A unit of radiation exposure used for measuring exposure to radon gas in the U.S. One working level represents a concentration of short-lived radon decay products in one liter of air resulting in the ultimate emission of 1.3 x 105MeV or 20.8 nanojoules (nJ) of energy. Exposures are measured in working level months (WLM). Cumulative exposure of workers is measured in working level months (WLM), representing exposure to one working level for 170 hours. In underground mining, U.S. law says miners must not be exposed to levels exceeding 1 WL and cumulative exposure must not exceed 4 WLM per year. In other industries, exposures are limited to 0.3 WL. In homes, the U.S. Enviromental Protection Agency recommends exposure levels not exceeding 4 pCi/L, or 0.04 WL
