Does being in the air provide any protection from an asteroid? How does radiation and shock waves from a radioactive asteroid or atomic explosion disperse throughout Earth's atmosphere?

Are there specific areas on Earth that are less likely to receive the shock wave or radiation by being on the other side of the Earth and/or land or wind characteristics like being in a deep valley? 

I'm trying to go with the worst case survivable scenario if the asteroid hit with the possibility of hitting a nuclear reactor, arsenal or deposit of uranium.



Related:


  This is from a broad question that I am breaking up in 3 questions. Feel free to edit.


Which of these scenarios would have a smaller chance of being struck?


In the air of some type blimp or aircraft on the opposite side of the Earth?


Does being under water provide any protection from a asteroid?
To answer the radiation question, it is both absorbed and reflected into space. A lot of these processes are complex relations between atmosphere, magnetosphere, and solar radiation. Solar radiation does penetrate through as it drives everything we need or any creature needs to live, whether directly or indirectly. Aurora Borealis is caused by Solar radiation trapped in our atmosphere. This is why Ozone (O3) is so important as it does a massive support function of helping block those rays. Some of this radiation is reflected by the earth as thermal radiation. The magnetosphere also plays a role in capturing and diffusing such particles. A little more research may help, it is a very fascinating process. For more:

https://en.wikipedia.org/wiki/Aurora

This was from courses in astronomy, hydrology, and my brain. Use wisely.