To detect magnetic fields, you can buy or rent a gaussmeter, or have a professional perform an inspection. Reductions can be as simple as avoiding high exposure locations. Electrical wiring can be repaired to installed according to low-EMF methods. Specific sources can be shielded. Low emission computers, telephones and appliances are becoming available.
Some individuals handle it better, perhaps having a stronger resistance to life's stresses.
Others are more sensitive, and in extreme cases may experience allergies, depression, environmental illness, or chronic fatigue syndrome. If you are the type of person who feels better when the electricity suddenly goes off during a power failure, or when walking out in the woods away from any electricity, you may be sensitive to electric fields. Most electric field exposures come from building wiring. The remainder come from cords, appliances and nearby power lines. Electric fields are easy to reduce.