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Electromagnetic Fields

What are Electromagnetic Fields?

Electric and magnetic fields, commonly called electromagnetic fields (EMFs), are invisible areas of energy that result from an electric charge. EMFs are linked to the use of electrical power and various forms of natural and artificial lighting. 
The energy area or waves given off by EMFs are called radiation. EMFs with low-level radiation are generally considered harmless to humans. EMFs with high-level radiation can harm humans who are around them for a long period. 
Everyday sources of EMFs with low-level radiation include:

  • Power lines
  • Electrical wiring
  • Microwave ovens
  • Computers
  • Cell phones and cell phone towers

Sources of EMFs with high-level radiation include:

  • Ultraviolet rays
  • X-rays
  • Gamma rays

Why are Electromagnetic Fields a concern?

Exposure to high-level EMFs that might be harmful is restricted by national and international guidelines. The general public cannot access places where dangerous human exposure may occur.

Exposure to low-level EMFs happens every day for most people. We encounter EMFs through our use of home appliances, cell phones, and computers. We are also exposed to EMFs near power lines and electric substations, and even during thunderstorms. 

Some people worry that our frequent exposure to low-level EMF radiation could cause cancer or other health problems. However, research has generally shown that exposure to low-level EMFs does not harm human health.

Who is at risk?

There is no evidence that short-term exposure to low-level EMFs is harmful to human health, according to the World Health Organization. However, the research on this is ongoing. The National Institute for Occupational Safety and Health does not consider microwaves to be a health hazard.

What pollutants are of greatest concern?

Sources of EMFs with harmful high-level radiation include:

  • Ultraviolet rays – electromagnetic waves that are shorter than the violet end of the visible spectrum but longer than that of X-rays. Humans are exposed to ultraviolet rays from the sun. Artificial sources include tanning booths and certain types of lamps and lasers. 
  • X-rays – electromagnetic waves of high energy and very short wavelength that can pass through many materials. X-rays help us visualize bones and help diagnose diseases, and are used in medical settings.
  • Gamma rays – penetrating electromagnetic radiation that involves the decay of atomic nuclei. Gamma rays are used to kill cancer cells, to clean medical equipment, and in radioactive tracers.

Reduce your risk

  • Do you live near a cell phone tower or power lines?
  • If you have concerns about exposure to EMFs, you can hire someone to measure the strength and frequency nearby to determine if your exposure level is harmful.
    • To check cell phone towers, contact a government agency or private firm. 
    • To check a power line or substation, contact your local power company. 
  • You can also measure EMFs yourself with an EMF meter.

National Library of Medicine Resources and Databases

  • Electromagnetic Fields
    Curated links to current consumer health information on the effect of electromagnetic fields on human health. These English and Spanish web resources include background information, related issues, specifics, statistics and research, clinical trials, journal articles, relevant agencies, and targeted resources for children.

Additional Resources

  • Electric and Magnetic Fields
    National Institute of Environmental Health Sciences
    Information on electronic and magnetic fields, including answers to frequently answered questions, and links to research and additional resources from a federal institute that investigates the interplay between environmental exposures, human biology, genetics, and common diseases to help prevent disease and improve human health.
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