Free Encyclopedia of Building & Environmental Inspection, Testing, Diagnosis, Repair
Ask a Question or Search InspectAPedia
InspectAPedia ® Home
ENVIRONMENTAL HAZARDS - INSPECT, TEST, REMEDY
AIR FILTERING STRATEGIES
AIR POLLUTANTS, COMMON INDOOR
AIR QUALITY IMPROVEMENT STRATEGIES
AIRBORNE PARTICLE ANALYSIS METHODS
ALLERGEN TESTS for BUILDINGS
ANIMAL ODORS IN BUILDINGS
ASBESTOS IDENTIFICATION IN BUILDINGS
ATTORNEYS and EXPERT WITNESSES
BACKDRAFTING HEATING EQUIPMENT
BIBLIOGAPHY for ENVIRONMENTAL HEALTH, MOLD, IAQ
BLACK MOLD, HARMLESS COSMETIC
BLACK MOLD, TOXIC & ALLERGENIC
BOOKSTORE - ENVIRONMENTAL
BUILDING SAFETY HAZARDS GUIDE
Cadmium in the home
CARBON MONOXIDE - CO
Carbon Nanotube Hazards
CARPETING & INDOOR AIR QUALITY
CHEMICAL CONTAMINANTS in WATER
CHINESE DRYWALL HAZARDSDS
COMBUSTION PRODUCTS & IAQ
CPSC Indoor Air Pollution Book Online Copy
DIRECTORY of MOLD / ENVIRONMENTAL EXPERTS
Diethylstilbestrol - DES
DUST SAMPLING PROCEDURE
EMERGENCY RESPONSE, IAQ, GAS, MOLD
EMF ELECTROMAGNETIC FIELDS & HUMAN EXPOSURE
ENVIRO-SCARE - PUBLIC FEAR CYCLES
FEAR of MOLD - MYCOPHOBIA
FLAME COLOR, BLUE vs YELLOW COMBUSTION
FLOOD DAMAGE ASSESSMENT, SAFETY & CLEANUP
FLOOR TILE ASBESTOS IDENTIFICATION
GAS EXPOSURE EFFECTS, TOXIC
GAS EXPOSURE LIMITS & STANDARDS
HEATING OIL EXPOSURE HAZARDS, LIMITS
HOME HEATING SAFETY
INDOOR AIR QUALITY & HOUSE TIGHTNESS
INDOOR AIR QUALITY IMPROVEMENT GUIDE
LEAD POISONING HAZARDS GUIDE
Legionella Legionnaires' Diseaset
LIGHT, GUIDE to FORENSIC USE
LP & Natural Gas Safety Hazards
METHANE GAS SOURCES
MSDS Material Safety Data Sheets
MYCOPHOBIA, STAINS MISTAKEN for MOLD
MYCOTOXIN EFFECTS of MOLD EXPOSURE
ODORS GASES SMELLS, DIAGNOSIS & CURE
OIL, HEATING, EXPOSURE HAZARDS, LIMITS
PARTICLE SIZES & IAQ
Particulates & Allergens Indoors
Pesticide Exposure Hazards
PET ALLERGENS / PET DANDER
PLASTIC ODORS-SCREENS, SIDING
PLUMBING SYSTEM ODORS
PVC - VINYL BUILDING PRODUCTS
RADON HAZARD TESTS & MITIGATION
SAFETY HAZARDS GUIDE
SAFETY HAZARDS & INSPECTIONS
SEPTIC METHANE GAS
SEWAGE BACKUP TEST & CLEANUP
SICK HOUSE IAQ QUESTIONNAIRE
STAIN DIAGNOSIS on BUILDING EXTERIORS
STAIN DIAGNOSIS on BUILDING INTERIORS
UFFI UREA FORMALDEHYDE FOAM INSULATION
VENTILATION in BUILDINGS
VINYL CHLORIDE HEALTH INFO
VINYL Siding or PLASTIC Window ODORS
Volatile Organic Compounds VOCs
WATER ODORS, CAUSE CURE
WATER TESTS, CONTAMINANTS, TREATMENT
World Trade Center Collapse Dust Photos
Effects of EMF exposure as a function of distance from the power transmission line or other source of electromagnetic fields: an easy-to-understand summary. This paper discusses the effect of distance from a power transmission line (or other EMF sources) when performing electromagnetic field (EMF) or electro-magnetic radiation EMR measurements to measure EMF exposure levels in gauss or milligauss. We discusses sources of error and variation in EMF measurements and we review and make suggestions for using several low-cost EMF measurement devices to determine the instantaneous electromagnetic field exposure.
Green links show where you are. © Copyright 2013 InspectAPedia.com, All Rights Reserved. Author Daniel Friedman.
But distance from the power transmission line, while important, is not the only important factor. The strength of the electromagnetic field varies dramatically as the current passing through the power line varies.
Thus in the middle of summer in the Northeastern United States, when many people are running air conditioners and thus the load on the electrical grid is high, a lot of current is passing through the power transmission lines, and the EMF strength will be quite high - thus extending further from the power lines and being measurable at higher levels than it will during times of low electricity usage. Therefore no single instantaneous EMF measurement at a particular spot may be quite repeatable.
A power transmission company can tell you the kilovoltage that a given transmission line is designed to carry. This is not enough data to calculate exposure or risk. One would need to know the actual minute-to-minute load on the transmission line to be able to predict the probable EMF strength during those intervals.
The absence of this data has plagued attempts to correlate proximity to power transmission lines, EMF exposure, and health risks. The "Swedish study" mentioned herein was able to overcome this difficulty and obtain actual usage data and thus was able to calculate the actual EMF exposure levels.
Often but not always, the relative strength of such fields falls off in much shorter distance than that from power transmission facilities. However in some instances where occupants wish to maintain prudent avoidance, it is possible to make a significant reduction in exposure by small changes in arrangement of devices or locations of working or sleeping areas.
Power companies in the US have been singularly uncooperative in providing actual load data, making it difficult to establish a dose-exposure relationship between exposure to EMF and occurrence of disease. This is why the Swedish studies are so important. There the government cooperated with researchers in providing load data, permitting clear establishment of exposure to occurrence relationships.
Instead of contacting us with a request to perform EMF Electromagnetic or RF Radio Frequency Field Strength measurements, in most cases it is more economical and convenient for a property owner to purchase their own instrument, making measurements under varying conditions. In this series of articles we describe how to make measurements using a consistent approach and using good documentation. See Recommended EMF Measurement Procedure for details of how to collect EMF measurement data.
Following good procedure and using instruments properly are two steps towards making accurate, repeatable EMF measurements. But because the signal transmission for RF sources such as radio, TV, or cell towers, the load on a power transmission line is not under control of an individual property owner, and because the EMF strength varies as the power transmission line load varies, it is important to have an idea of that condition as well when attempting to characterize EMF exposure at a specific location. In contrast, EMF measurements are quite accurate and repeatable at other EMF sources such as close to electrical appliances and service entry cables.
Please do not contact us with a request buy EMF or RF measuring equipment. We do not sell anything. To do so would be a conflict of interest for this website. These devices are readily available from many electrical equipment and home inspection equipment suppliers. See Evaluation of Low-Cost EMF Instruments This article describes several low-cost and reasonably accurate EMF measurement devices that are readily available. See Radio Frequency RF Detection Meters This article describes several low-cost and accurate radio frequency or RF detection and measurement devices suitable for radio, TV, cellphone, microwave, and similar signals.
Frequently Asked Questions (FAQs)
Use the search box below to ask a question or to search the InspectApedia.com website.
Ask a Question or Enter Search Terms in the InspectApedia search box just below.
Technical Reviewers & References
Related Topics, found near the top of this page suggest articles closely related to this one.