Will RF cause any health problem? [duplicate]

Question

This is out of curiosity. I am working with rf 433 MHZ transmitter receiver module. I just wanted to ask whether it affects health in any way. I have read that such radiation has carcinogenitic effects. Does the power transmitted by the transmitter has any effect?

Answer 1

There are two actions through which electromagnetic radiation can cause health problems.

If the radiation is ionising (ie has a high enough energy to liberate electrons from their atoms) then it has the potential to cause wide ranging unpleasant effects. Fortunately EM radiation is only ionising at frequencies somewhere in the far ultraviolet region - not an issue for RF applications.

The other way that EM radiation can cause damage is through dielectric heating. This happens over a range of frequencies, and is the method that a home microwave uses to heat food. At the frequencies that you're dealing with, this is the only potential vector for health issues.

Whether the RF radiation you're dealing with can cause health issues is completely down to the power levels that you're using. Most RF emitting devices you use in your home (WiFi router, garage door opener, hobbyist RF transceivers etc) only transmit a maximum of a few hundred milliwatts of power. A cell phone might transmit at 2W. Thanks to the inverse square law, the actual power of the transmission that can possibly interact with your body drops off with a square of the distance (and so very quickly). The efficiency of that RF in heating your body will also be considerably less than 100% (you could probably work this out using the heating equation given in 1). This all adds up to a very small amount of the transmission power actually being absorbed by your body. For reference, the body apparently generates about 1W/kg of heat while at rest, rising to 2-3W/kg while active. The very small amount of heat generated by the RF will be easily dissapated by your body's existing cooling system (you are incredibly effective at maintaining a stable temperature), and is dwarfed by the heat generated by muscle movement.

So to summarise? If you're dealing with standard consumer RF transmitters, you're safe. If you've built an RF transmitter which could potentially broadcast at high power levels, then you could experience adverse effects.

It's always worth noting when discussing this topic: 1. Humans have only been routinely carrying RF transmitters close to our bodies for a couple of decades. It may be that time shows us that this isn't a great idea, and 2. There's a lot of crazy people who will say a lot of stuff on this topic that is wrong. The kind of low power RF transmissions used for WiFi are exceedingly unlikely to have any effect at any distance. Every study I'm aware of has demonstrated in double blind tests that claimed "electromagnetic sensitivity" is entirely psychological.

Answer 2

From this source:

How can RF energy hurt me

Moderate level exposures cause heat stress and behavioral changes. The effects are often mistaken for the flu because the symptoms are similar. As the level of exposure increases, the potential for harm increases. Human cells die at 107° Fahrenheit. This is the reason why doctors get concerned if someone’s temperature goes above 105°. The body is constantly replacing cells, so the amount of damage that is done depends on how many cells are killed and the type of cells that are killed. Kill off some cells, and the effects may pass in minutes or hours. Destroy a lot of liver cells for instance, and you will have liver damage. If the damage is not too severe, the body can repair itself. However, if the damage is extensive, the effects may be permanent! Perhaps the most vulnerable organs are the eyes. The eyes have virtually no blood flow that can provide cooling from other parts of the body, and their dimensions make them very good antennas at microwave frequencies.

And the following is from here:

Are there any health effects?

A large number of studies have been performed over the last two decades to assess whether mobile phones pose a potential health risk. To date, no adverse health effects have been established as being caused by mobile phone use.

Short-term effects

Tissue heating is the principal mechanism of interaction between radiofrequency energy and the human body. At the frequencies used by mobile phones, most of the energy is absorbed by the skin and other superficial tissues, resulting in negligible temperature rise in the brain or any other organs of the body.

A number of studies have investigated the effects of radiofrequency fields on brain electrical activity, cognitive function, sleep, heart rate and blood pressure in volunteers. To date, research does not suggest any consistent evidence of adverse health effects from exposure to radiofrequency fields at levels below those that cause tissue heating. Further, research has not been able to provide support for a causal relationship between exposure to electromagnetic fields and self-reported symptoms, or “electromagnetic hypersensitivity”.

Long-term effects

Epidemiological research examining potential long-term risks from radiofrequency exposure has mostly looked for an association between brain tumours and mobile phone use. However, because many cancers are not detectable until many years after the interactions that led to the tumour, and since mobile phones were not widely used until the early 1990s, epidemiological studies at present can only assess those cancers that become evident within shorter time periods. However, results of animal studies consistently show no increased cancer risk for long-term exposure to radiofrequency fields.

Several large multinational epidemiological studies have been completed or are ongoing, including case-control studies and prospective cohort studies examining a number of health endpoints in adults. The largest retrospective case-control study to date on adults, Interphone, coordinated by the International Agency for Research on Cancer (IARC), was designed to determine whether there are links between use of mobile phones and head and neck cancers in adults.

The international pooled analysis of data gathered from 13 participating countries found no increased risk of glioma or meningioma with mobile phone use of more than 10 years. There are some indications of an increased risk of glioma for those who reported the highest 10% of cumulative hours of cell phone use, although there was no consistent trend of increasing risk with greater duration of use. The researchers concluded that biases and errors limit the strength of these conclusions and prevent a causal interpretation.

Based largely on these data, IARC has classified radiofrequency electromagnetic fields as possibly carcinogenic to humans (Group 2B), a category used when a causal association is considered credible, but when chance, bias or confounding cannot be ruled out with reasonable confidence.

While an increased risk of brain tumors is not established, the increasing use of mobile phones and the lack of data for mobile phone use over time periods longer than 15 years warrant further research of mobile phone use and brain cancer risk. In particular, with the recent popularity of mobile phone use among younger people, and therefore a potentially longer lifetime of exposure, WHO has promoted further research on this group. Several studies investigating potential health effects in children and adolescents are underway.