Recently the prestigious journal Science released some favorite science news stories of the year 2014, and the study “Determining optimal fallout shelter times following a nuclear detonation” is one of the most popular articles by readers.

Let's imagine the scene: It begins with a flash brighter than the sun. You luckily survive the shock wave from initial blast. But the deadly radioactive fallout is on its way. What should you do then?

The official U.S. government advice is to “take shelter in the nearest and most protective building.” For most people, that would be the basement of their home, offering little protection from fallout. In such cases the official recommendations suggest “early transit” to find better shelter with thick layers of concrete over your head and plenty of food and water. But the problem comes -- if you spend too much time outside in the fallout, you’re toast.

Scientists have figured out what you should do if the case happens. Michael Dillon, an atmospheric scientist at Lawrence Livermore National Laboratory in California, has built up a new mathematical model to answer the question raised by his curious family member. In his paper published last year, he demonstrated the sheltering strategies for people far enough from ground zero to survive the initial blast but close enough to face deadly fallout.

We won't need to look into the number of complicated mathematical equations here. Just keep in mind that your total radiation dose is closely related to your distance from the detonation and the time you stay outside looking for and reaching a better shelter. Assuming that you are totally exposed while running to safe shelter, in the end, the calculation is simplified to a single critical number--"the ratio of the time you spend hunkering down in your first shelter to the time you spend moving to the high-quality shelter." Then Dillon worked out what would happen with a variety of shelter options and transit times, as shown in the pictures below.

The results are quite surprising. For low-yield nuclear detonations, you can do far better than just sheltering in place (the first option in the picture). If your current shelter is poor and higher quality shelter is less than 5 minutes away, you should run there as soon as you can (the 2nd option). If you got nothing but a higher quality shelter is available farther away, you should go for it no later than 30 minutes after detonation (the 3rd option). VERY IMPORTANT: You’ll need a watch and a good knowledge of your surroundings. Run!!!

Of course not everyone is convinced of the new model. But according to an official from NIH, Dillon’s model reveals what is “possible to do and what is not likely to be useful."

I just hope that we never have to use the guidelines. Let's pray for a peaceful world together at the beginning of the new year.

Please see the link below for the original post. Thanks!

http://blog.chinadaily.com.cn/blog-309597-25907.html