The exposure limits in the following tables, gathered from various sources, were derived from well established, severe biological effects (such as tissue heating and nerve stimulation) data. This information is not meant to present “SAFE” vs. “UNSAFE” levels when it comes to the much lower exposure thresholds studied in the epidemiological literature (with respect to cancer, melatonin suppression, and other biological effects). It is clearly not yet known what the truly safe levels of exposure are. With that in mind, here are the exposure guidelines that are available:
This information is used with permission from www.lessemf.com.
based on immediate biological effects at 50/60 Hz for general public
|ELECTRIC FIELD (V/m)||MAGNETIC FIELD (mT)|
|Head & Torso||18.1/frequency|
|State||ELECTRIC FIELD||MAGNETIC FIELD|
|w/i R.O.W.||Edge of R.O.W.||Edge of R.O.W.|
|Florida||8 kV/m*||2 kV/m||150 mG* (max. load)|
|10 kV/m**||200 mG** (max. load)|
|250 mG*** (max. load)|
|Montana||7 kV/m+||1 kV/m|
|New Jersey||3 kV/m|
|New York||11.8 kV/m||1.6 kV/m||200 mG (max. load)|
** For 500-kV lines.
*** For 500-kV lines on certain existing R.O.W.
+ Maximum for highway crossings.
++ Maximum for private road crossings.
R.O.W. = right-of-way.
|Sweden offers two measurement and emission guidelines for computers monitors:The first, known as MPR II, prescribes limits on electric and magnetic field emissions in the ELF and VLF ranges, as well as the static field.A more recent and more restrictive standard, promoted by the Swedish Confederation of Professional Employees (TCO), addresses the entire computer. In addition to field emissions, TCO ’95 includes guidelines for energy consumption, screen flicker, luminance and keyboard use.|
|Frequency Range||MPR II||TCO ’95|
|DC: Static Field||+/-500 V||+/-500 V|
|ELF: 5 Hz – 2 KHz (Band I)||up to 25 V/m||up to 10 V/m|
|VLF: 2 KHz – 400 KHz (Band II)||up to 2.5 V/m||up to 1 V/m|
|ELF: 5 Hz – 2 KHz (Band I)||up to 2.5 mG||up to 2.0 mG|
|VLF: 2 KHz – 400 KHz (Band II)||up to .25 mG||up to .25 mG|
|MPR II measurements are taken at a distance of 50 cm (approximately 20 inches) at 16 points around the monitor, at 3 different levels.TCO measurements are taken at a distance of 30 cm (approximately 12 inches) in front of and 50 cm around the sides of the monitor (except for Band II magnetic fields and the static field, which are measured at 50 cm in front of the screen).The TCO Development Center sponsors a website that provides additional information about the TCO organization and their guidelines.|
International Commission on Non-Ionizing Radiation Protection (IRPA/INIRC)
|Electric Field||Magnetic Field|
|Occupational:||Whole working day:||10 kV/m||5 G (5,000 mG)|
|Short term: *||30 kV/m||50 G (50,000 mG)|
|For limbs:||250 G (250,000 mG)|
|General Public:||Up to 24 hours per day:||5 kV/m||1 G (1,000 mG)|
|Few hours per day:||10 kV/m||10 G (10,000 mG)|
|* For electric fields of 10-30 kV/m:
[field strength (in kV/m)] x [hours of exposure] should not exceed 80 for the whole working day.
Whole-body exposure to magnetic fields up to 2 hours per day should not exceed 50 Gauss.
Source: IRPA/INIRC 1990.
|Electric Field||Magnetic Field|
|Occupational exposures should not exceed 25 kV/m (from 0 Hz to 100 Hz).
Prudence dictates the use of protective devices (e.g. suits, gloves, insulation) in fields above 15 k/Vm.
|Occupational exposure should not exceed 10 G (10,000 mG).|
|For workers with cardiac pacemakers maintain exposure at or below 1 kV/m.||For workers with cardiac pacemakers, the field should not exceed 1 G (1,000 mG).|
|Source: American Conference of Governmental Industrial Hygienists (ACGIH) 1994.|
|According to American National Standards Institute (ANSI) C95.1-1994|
|ANSI Uncontrolled refers to an environment in which the energy levels are not known, or where some people present may not be aware of the EM fields.
Controlled refers to an environment in which the energy levels can be accurately measured and everyone on the premises is aware of the presence of EM fields.The ANSI exposure limits are the average exposure over a 6 minute period.Notice that in the frequency range of 30 MHz to 300 MHz, the safe exposure limits are the lowest. This is the frequency range where the human body is a more efficient absorber of radiation. Notice also that the Swedish standards for computer monitors are far stricter that the ANSI standards in the low frequencies.