The ratio of the activity of the SLRDs to the activity of the radon gas is called the Equilibration Ratio (ER). Equilibrium usually occurs in about three to four hours. When an individual receives a dose of one WL in 170 hours (a miner's month), the exposure then becomes called a working level month or WLM.
I imagine it was probably my first Prehospital Trauma Life Support class back in 1990 that I first heard of the three collision rule. Since then, it has remained a useful tool in examining the mechanism of injury after auto accidents. If you havenât heard of it, please allow me to elaborate. The three collision rule states that, in any auto accident, there are three collisions that occur and the keen EMT needs to be aware of all three.
This resulted in 1.4 million deaths in 2013, up from 1.1 million deaths in 1990. About 68,000 of these occurred in children less than five years old. Almost all high-income countries have decreasing death rates, while the majority of low-income countries have increasing death rates due to traffic collisions.