Oh no, Radiation, Ahhhhhh!

I tried so hard to make this post short and simple and failed so badly, if you want you can just head to this wikipedia article on ionizing radiation or the epa's page on the topic and get a more coherent version of this post. Otherwise you can continue reading why the person who makes his money designing circuits that put radiation in the air thinks that radiation from electronics is safe.

Unfortunately very few people really know physics and very few people really know biology and especially since they are on somewhat opposite ends of the science spectrum an extremely small number of people really know both. This leads to a lot of confusion over how radiation impacts people.

I definitely can't claim to really know biology, but I do know some physics especially when it comes to a certain range of the electromagnetic spectrum. So I'm going to try to spread a bit of knowledge about the subject.

First of all, radiation sounds scary right? Well some of it is. If someone says there's a big source of alpha radiation near by then run. But when I tell you that in order to read this post you have to bombard your eyes with radiation and that each particle of that radiation is far more energetic than those created in a microwave, you should stay calm cause I'm talking about visible light.

Next an attempt to quickly explain what radiation is: radiation is a very general term describing particles or waves traveling through a medium. Unfortunately some radiation is described as waves while other radiation is described as particles and sometimes people go back and forth. Explaining that takes some mind bending quantum mechanics, but we can skip over that. Most of the time when radiation is discussed it's either alpha/beta radiation which is typically viewed as particles. In general big doses of alpha/beta radiation come from radioactive elements and can be scary stuff. The other type is electromagnetic radiation which is typically described as a wave. All electromagnetic radiation is the same thing, just with different frequencies. It's a bit easier to think of it as a particle in which case frequency describes how much energy each particle has and power describes how many of those particles are flying around. The span of frequencies is essentially infinite, but the range people typically encounter is about 10^6 Hz (AM radio) to 10^19 Hz (gamma rays - hopefully you don't encounter these too often). This chart from wikipedia nicely shows the spectrum. Notice that 10^6 to 10^19 is a crazy huge range - gamma radiation's frequency is 10 trillion times greater than the frequency of AM radio.

So what makes some radiation scary and some radiation completely safe? Well to answer that we have to know what it can do to a person. Alpha/beta/gamma radiation can do some really nasty stuff that can kill fairly quickly as well as cause cancer - I don't know much about what it is doing when it kills quickly - probably just messing up a bunch of molecules by knocking out electrons. The main fear of radiation is that it causes cancer. It can also heat the inside of the body.

Well what about cancer? Radiation causes cancer by knocking electrons out of molecules in DNA. Once an electron is knocked out it can change the chemical properties and change what the DNA encodes. Then a bunch of biology can happen and end up causing cancer. In order to knock out an electron the radiation particle hitting the electron must have enough energy to knock it out. The key here is that the individual particle must have enough energy. No matter how many times someone lightly pokes you, you'll never break a bone. So if the particles are low energy/low frequency it doesn't matter what the power is. If the particles do have enough energy then the power, and exposure time, do matter because the more particles hitting you the more likely one will hit an electron and cause all the steps required to cause cancer. This is the difference between ionizing and non-ionizing radiation and is the key concept in knowing how dangerous radiation is.

So what radiation is ionizing? Ultraviolet light and higher frequencies, so around 10^16 Hz and above. Cellphones, portable phones, wifi, baby monitors, and bluetooth all use frequencies around 10^8 to 10^10 Hz, one millionth the frequency of ionizing radiation. Most other electronic communication standards use lower frequencies cause generating higher frequencies is really hard. Note that visible light is between any radiation generated by electronics and the frequency of ionizing energy.

Ok, so all these electronics devices don't use ionizing radiation, but microwaves don't use ionizing radiation (2.4*10^9 Hz) and everyone knows that if they stick their head in a microwave bad stuff happens. True, this gets us to the third issue with radiation which is that it can heat parts of your body. Microwaves are the prime example of this since they are designed specifically to heat water, 2.4 GHz is the resonate frequency of water. The human body works really hard to keep its innards within a very specific range of temperatures and outside of that stuff starts to breakdown and cause problems. WiFi uses the same frequency as microwaves and cell phones are sorta close. So it seems reasonable that they could cause heating which would then cause issues. Except they don't put out nearly enough power. Try reheating leftovers by putting your cell phone next to them. A common response is even if the power is small, people spend a lot of time with cell phones next to their heads. True, but again the human body works really hard to keep its insides at the right temperature, so it's not going to have any problem adjusting to some tiny bit of power. Consider that the human body can handle it being 100 degrees outside or 0 degrees outside and still stay 98.6 degrees. Compared to that getting rid of the tiny bit of heat from cell phone radiation is nothing - heck getting rid of the heat from the hot phone touching your head is probably the bigger issue. Microwaves generate about 700 watts of radiation, cell phones max out around 2 watts.

Yeah you say all that, but what about those big studies that show that cellphones cause bad stuff? For that I refer you to my post about shoulder tapping.

A few bonus items:
-People who live near cell phone towers are actually exposed to less cell phone radiation. Most of the exposure is from their phone, which doesn't need to transmit as much power if it is close to a tower.
-If you notice that your ear feels kinda warm and weird after a long phone call on a cell phone, it isn't cause of the radiation, it's cause you were holding a hot, hard object against your ear for a long time. Normal phones have a more comfortable shape and don't get as hot.

If you're still worried about cell phone radiation:
-When you're talking the phone has to transmit a bunch of data so it is almost constantly sending out radiation. When you aren't talking it's just checking in with the tower every once in a while so the amount of radiation exposure is far lower.
-Radiation falls off with distance squared so moving the phone just a little further from your head significantly cuts down on the radiation, plus your ear will appreciate not being pressed against a hot object.
-Bluetooth only needs to cover from your ear to your phone, vs a phone that has to talk to a tower. So bluetooth head sets do transmit significantly less radiation.
-WiFi is actually the one that is the right frequency to heat water. But its range (and transmit power) is much less than a cell phone and people generally don't hold their computer or access point to their head. Sleeping near an access point isn't a big deal because there typically isn't a lot of traffic on your wireless network while you're asleep.
-It might seem that something like streaming a movie would cause more radiation from your phone/laptop because more data is moving over the wireless connection. But when downloading data the only transmitting the device needs to do is send acknowledgements that it's getting the data. That's more transmitting than when the device is doing nothing, but far less than if you're sending a movie to someone.
-Frequency, power and duration are all key to understanding the impacts of radiation so watch carefully what terms are being used when reading about the topic.