Electromagnetic Fields (EMF) are invisible energy waves emitted by both natural sources and human-made technology. The two primary categories found in the home are radiofrequency (RF), which is high-frequency from wireless devices, and extremely low frequency (ELF), which comes from electric power lines and appliances. Reducing exposure requires a systematic approach, starting with managing the devices you interact with most closely.
Identifying and Managing Common Proximity Sources
The most immediate and controllable source of exposure comes from devices held close to the body, like mobile phones and tablets. The inverse square law dictates that the strength of an electromagnetic field drops off sharply with distance, making a few inches a significant reduction. When using a mobile phone, keep it away from your head by utilizing the speakerphone function or an air-tube headset, as standard wired ones can transmit fields.
Laptops and tablets emit fields from their internal components and wireless antennas, so they should not be used directly on the lap. Place them on a desk or table to increase the distance between the device and your body. Also, switch mobile devices to airplane mode whenever active wireless connectivity is not needed, such as overnight, to halt transmissions.
Wi-Fi routers are constant sources of radiofrequency exposure, but simple changes can limit their impact. Connect stationary devices like desktop computers, printers, and smart TVs to the internet using an Ethernet cable to eliminate their wireless emissions. Powering off the router at night or during long periods away from home is an effective way to reduce continuous field exposure.
Strategies for Reducing Low-Frequency Fields in the Home
Extremely Low Frequency (ELF) fields are generated by the flow of electricity through home wiring and large appliances. ELF magnetic fields are challenging because they are created by the current and penetrate most common building materials easily. Reducing exposure relies primarily on maintaining distance from the source or addressing wiring errors that cause unusually high fields.
Magnetic fields can spike when there is a “net current” or ground current issue, indicating electricity is flowing on an unintended path, such as through water pipes or structural metal. This requires an electrician to diagnose and correct the issue by ensuring the hot and neutral wires are properly paired. Major appliances like refrigerators and washing machines generate magnetic fields; stepping back two to three feet while the appliance is running significantly reduces exposure.
Electric fields, created by voltage, are easier to manage as they are effectively blocked by walls and building materials. They can be reduced by turning off circuits via a kill switch or the circuit breaker, especially in the bedroom, since wires remain energized even when lights are off. Electric blankets and heating pads produce high electric fields; if used to warm a bed, they should be completely unplugged before you get into bed, not just turned off.
Understanding and Implementing EMF Measurement
Effective mitigation begins with measurement, as electromagnetic fields are invisible and their sources can be surprising. A single meter cannot accurately measure all types of EMF, so specialized devices are necessary for each category. Radio Frequency (RF) meters measure high-frequency wireless transmissions from sources like Wi-Fi, cell towers, and smart meters.
Extremely Low Frequency (ELF) fields require separate meters: a gaussmeter for magnetic fields and a dedicated meter for electric fields. Using these devices allows you to identify specific “hot spots” in your home, such as faulty wiring or a poorly placed router. Measurement should be used to pinpoint the highest sources of exposure and then verify that reduction efforts have been successful.
Utilizing Shielding and Mitigation Materials
When distance and behavioral changes are not feasible, physical shielding materials can be used as a final layer of defense. These materials are categorized by the type of field they are designed to block, primarily RF or electric fields. RF shielding materials, such as conductive paints, fabrics, and window films, are designed to reflect or absorb high-frequency wireless signals.
RF shielding paint contains carbon or graphite and can be applied to walls to block external wireless signals, but it must be properly grounded to also mitigate electric fields. Shielding fabrics, often woven with silver or copper threads, can be used for bed canopies or curtains. Magnetic fields require specialized shielding, such as high-permeability metal alloys like Mu-metal, which is complex and costly to install for residential use.