Many people in the world believe that cell phones can cause cancer, or at the very least consider it a possibility. As a result, millions of dollars have been spent investigating the link between cell phones and cancer with little to no evidence. What if I were to tell you that if you fear cancer from cell phones, it would only make sense for you to fear getting cancer from practically everything around you .
If you look at the chart to the left, you will see the electromagnetic spectrum, which shows all the different frequencies/wavelengths of light and their every day uses. As you go from left to right on the chart, you get to correspondingly higher frequencies and as a result higher energy electromagnetic radiation. Specifically, the energy of a particle of light (a photon) is directly related to its frequency times Plank’s constant. You’ll notice that cell phones operate at a frequency of around 1 GHz (10^9 Hz). The every day colors we see with our eyes, which are a form of electromagnetic radiation, come in at about 10^15 Hz. This means that the color we see packs 1,000,000 times more energy than the waves emitted by our cell phones. If we look at the lowest electromagnetic radiation known to cause cancer, the ultraviolet spectrum, we can add a power of ten. This means that for a given amount of ultraviolet light, it would take 10,000,000 times the amount of cell phone radiation to match the same amount of energy.
Well you might say that we talk a lot on our cell phones so maybe this could add up to a significant amount over time. The thing is, this just is not how cancer develops in the body. Let me explain.
The ability of radiation to cause cancer is dependent on whether or not the radiation is able to alter chemical bonds. This occurs when electrons involved in bonding in a molecule absorb radiation with enough energy to allow them to escape – this is called ionization. The thing is, whether or not radiation is ionizing is based solely on its energy, not on its number, and as we saw above, its energy is determined entirely from its frequency.
The cutoff between ionizing and non-ionizing radiation is under debate, particularly because it changes based on the molecule in question, but is generally accepted to occur somewhere around 2,500,000 GHz, which corresponds to the energy required to ionize oxygen. This is over one million times greater than the frequency of cell phone radiation, so its safe to assume that cell phone radiation is non-ionizing. If you’re having trouble with this concept, think of it like shooting a basketball – if you can’t get the ball high enough in the air, it doesn’t matter how many shots you take, you’ll never make a single one. The same concept holds for breaking chemical bonds with electromagnetic radiation.
While its pretty clear that cell phones cannot cause cancer from breaking chemical bonds, if we finished the discussion here we would be missing a critical piece. One effect of cell phone radiation is whats called “Dielectric Heating”. While it may sound complicated, its exactly how your microwave works (which you’ll notice is in a similar frequency band). In simple terms, here’s what happens: certain types of molecules, such as water, are partially polarized, meaning they are slightly positively charged at one end and slightly negatively charged at the other. Then, when a rotating field, like one provided by electromagnetic radiation passes over them, the molecules rotate to align with the field just as a magnet moves when another magnet comes near it. These rotating molecules then bump into other molecules, increasing the kinetic energy of the system and thus its temperature (temperature is just based on the average kinetic energy).
Now that we understand dielectric heating, we can understand how cell phone radiation might causing heating in our bodies, specifically around our heads. While this might make you worry that our cell phones are frying our brains, equivalent to sticking our heads in the microwave, you shouldn’t worry, here’s why. The temperature increase caused from cell phones is a power of ten less than just walking around outside in the sun! On top of that, the theory around how this could lead to cancer is that the increase in temperature induces some sort of inflammatory response or epigenetic change that could lead to cancer. The minuscule impact on temperature combined with a far-fetched causal mechanism makes this hypothesis highly unlikely to be true.
Not surprisingly, the evidence supporting cell phone causing cancer is completely lacking as well. For instance, a Danish study followed 420,000 people over 20 years and found no link between cancer and mobile phone use and numerous studies of similar scale have concluded the same. To be fair, some studies found a statistical link between cell phones and benign tumors, but included low sample sizes and have not been replicated.
Basically, from a scientific perspective we can never accept the null hypothesis (that cell phones don’t cause cancer) definitively, but we most certainly cannot accept the alternative hypothesis (that they do) and I would be willing to bet that either there is no link or that the effect size is so incredibly small as to be completely ignored.
Now that I’ve hopefully convinced you that it is highly unlikely for cell phones to cause cancer, I just want to scare you a little bit and tell you some things in your every day life that definitely do and most certainly with a larger effect size than cell phones.
Before I can scare you, I have to explain how cancer risk from radiation is measured. Radiation exposure is measured in Sieverts, which is an interesting unit in that it is probabilistic. For instance, exposure to 1 Sievert of radiation implies a 5.5% chance of eventually developing cancer as a result. Most things we will show are orders of magnitude smaller than a Sievert, and thus carry with them much lower chances of eventually developing cancer.
As the chart above shows, some every day things like eating a banana, TSA screenings, or flying on a plane pack with them a definite risk of developing cancer, albeit very small, but verified and real. Bananas for instance, which we all know are a great source of potassium, are also a great source of the radioactive isotope of potassium, which simply occurs in nature at a certain ratio to non-radioactive potassium. Even just going about your day packs with it 390 microsieverts annually of cosmic radiation coming from space simply from just existing on the planet Earth (if you live at higher elevations its even more).
While I said I’m trying to scare you, I’m really just trying to highlight how silly it is to worry about cancer from cell phones. It is highly unlikely that cell phone radiation can even physically cause cancer and in the small off chance it can, the effect is likely so tiny as to not worry about it at all, especially when a million other things contribute to causing cancer way more. So go ahead and talk on your cell phones as much as you want, just don’t text and drive.