Research Library
26 published studies on light, melatonin, power lines, transformers, cell towers and dirty electricity, each summarized in plain language with a link to the original source. These are the reasons FieldWise EMF Consulting measures what it measures.
Light is the most studied part of the indoor environment. These studies show how the intensity, color and timing of light affect melatonin, sleep, mood and alertness.
Ordinary room light under 200 lux suppressed melatonin by a median of 73.7% when left on overnight, and light before bed shortened the melatonin window by about 90 minutes.
What it means: Everyday evening lighting is bright enough to hold back your body’s night signal.
Gooley JJ, et al. Journal of Clinical Endocrinology & Metabolism, 2011. Read the study
In real homes, 48% had evening lighting bright enough to suppress melatonin by an estimated 50%. Homes with energy efficient lighting had nearly double the circadian signal of homes with incandescent bulbs.
What it means: The type of bulb in your living room matters, and LEDs can make evenings brighter to your biology.
Cain SW, et al. Scientific Reports, 2020. Read the study
Melatonin directly scavenges free radicals, stimulates the body’s antioxidant enzymes and boosts the efficiency of other antioxidants.
What it means: Protecting melatonin at night is about more than sleep.
Reiter RJ, et al. Acta Biochimica Polonica, 2003. Read the study
Office workers under blue enriched daytime light reported better alertness, performance and concentration, less evening fatigue and better sleep quality.
What it means: The right light during the day supports better nights.
Viola AU, et al. Scandinavian Journal of Work, Environment & Health, 2008. Read the study
When office lighting changed from 4000 K to blue enriched 8000 K, workers’ sleep and activity timing tracked office hours instead of natural dawn. The authors called blue enriched light a potent time signal for the body clock.
What it means: Indoor light can override the sun as the signal your body keeps time with.
Vetter C, et al. Scandinavian Journal of Work, Environment & Health, 2011. Read the study
Office workers who received more circadian effective light in the morning fell asleep faster, slept better and reported lower depression scores.
What it means: Bright mornings help set up good nights.
Figueiro MG, et al. Sleep Health, 2017. Read the study
Office workers with windows received 173% more white light during work hours and slept an average of 46 minutes more per night than workers without windows.
What it means: Daylight exposure during the day is linked to longer, better sleep.
Boubekri M, et al. Journal of Clinical Sleep Medicine, 2014. Read the study
Flicker from conventional fluorescent lighting changed brain activity (EEG) in flicker sensitive people and was linked to faster but less accurate work.
What it means: Flicker you can’t see can still affect how you feel and perform.
Küller R, Laike T. Ergonomics, 1998. Read the study
Power frequency magnetic fields come from current flowing through power lines, wiring and appliances. They pass through walls and are some of the most studied fields in the environment.
Adults living near a 735 kV line averaged 7.1 mG at home and 6.8 mG during sleep, compared with 1.6 mG and 1.1 mG far from any line. Electric fields averaged 26.3 V/m versus 14.0 V/m, and the magnetic field tracked the line’s load.
What it means: Exposure near a line changes with the time of day, which is why 24 hour logging matters.
Levallois P, et al. Environmental Health Perspectives, 1995. Read the study
In 142 electric utility workers, those with the most steady magnetic field exposure had lower levels of a melatonin metabolite after work, and the effect was stronger among workers with the least daytime light.
What it means: Fields and light may work together, so it pays to measure both.
Burch JB, et al. American Journal of Epidemiology, 1999. Read the study
Temporally stable magnetic field exposure was associated with reduced nighttime melatonin metabolite excretion. The largest reductions appeared when home and work exposures were combined.
What it means: Where you sleep and work both count.
Burch JB, et al. Scandinavian Journal of Work, Environment & Health, 1998. Read the study
IARC classifies power frequency magnetic fields as Group 2B, possibly carcinogenic to humans, based mainly on studies linking long term average fields above about 3 to 4 mG with childhood leukemia.
What it means: The World Health Organization takes long term magnetic field exposure seriously.
International Agency for Research on Cancer IARC Monographs, Volume 80, 2002. Read the study
Children born within 200 m of high voltage lines had a relative risk of 1.69 for leukemia, and 1.23 at 200 to 600 m, compared with children born farther away.
What it means: Proximity to large lines has been associated with childhood leukemia.
Draper G, et al. BMJ, 2005. Read the study
Children living within 50 m of 200 kV lines with fields above 0.4 µT (4 mG) had an odds ratio of 4.06 for childhood leukemia.
What it means: Distance and measured field strength together tell the real story.
Crespi CM, et al. Environmental Research, 2019. Read the study
In 182 cases and 726 controls, children living under 100 m from high voltage lines had an odds ratio of about 2.0 compared with those 400 m or more away. The authors concluded close proximity was associated with excess risk.
What it means: A newer study pointing the same direction.
Malagoli C, et al. Environmental Research, 2023. Read the study
Among 138,905 electric utility workers, brain cancer mortality rose with magnetic field exposure, with a rate ratio of 2.6 in the highest exposure category.
What it means: Long term occupational exposure has been linked to brain cancer mortality.
Savitz DA, Loomis DP. American Journal of Epidemiology, 1995. Read the study
A meta-analysis found higher occupational magnetic field exposure linked to increased ALS risk (relative risk 1.14), and 1.41 in electrical occupations.
What it means: A pattern worth knowing about for anyone with long daily exposure.
Huss A, Peters S, Vermeulen R. Bioelectromagnetics, 2018. Read the study
A meta-analysis of 22 studies found a pooled relative risk of 1.63 for Alzheimer’s disease with occupational magnetic field exposure.
What it means: Another long term association researchers continue to study.
Jalilian H, et al. NeuroToxicology, 2018. Read the study
What sits beside, below or behind a room can matter more than anything inside it. These studies measured fields around building and utility equipment.
In 41 apartments across 10 buildings, apartments directly above an indoor transformer station averaged 4 mG, while all other apartments averaged 0.6 to 1.2 mG.
What it means: Equipment under a floor can raise fields in the room above it.
Hareuveny R, et al. Journal of Exposure Science and Environmental Epidemiology, 2011. Read the study
Spot readings in a computer server room ranged from 0.5 to 1,000 mG. The highest fields were near the electrical panel, power distribution units and cooling units, not the servers themselves.
What it means: Hot spots follow the power equipment, so map the whole space.
NIOSH Health Hazard Evaluation 2008-0286-3084 National Institute for Occupational Safety and Health, 2009. Read the study
Measurements across a utility workforce showed magnetic and electric fields varied widely with nearby equipment, the task and proximity.
What it means: Exposure has to be measured, not assumed from a job title or building type.
Deadman JE, et al. Scandinavian Journal of Work, Environment & Health, 1996. Read the study
Wireless signals come from many sources at once: towers, Wi-Fi, smart meters and devices. These studies show why a meter tells you more than a map.
In 354 homes within 250 m of a cell tower, the tower was the dominant wireless source in 64% of homes. Exposure depended on window position, line of sight to the antenna and the floor of the home.
What it means: Two neighbors the same distance from a tower can have very different exposure.
De Giudici P, et al. Environmental Research, 2020. Read the study
Personal meters showed exposure from cell base stations peaked around 280 m and 1,000 m from the antennas, where the main beam reaches the ground.
What it means: Living right next to a tower is not always where exposure is highest.
Viel JF, et al. Occupational and Environmental Medicine, 2009. Read the study
Frequency selective measurements in public indoor workplaces found radio frequency from many sources at once, each identifiable by its frequency band.
What it means: Each source can be identified and addressed on its own.
Gryz K, et al. International Journal of Occupational Medicine and Environmental Health, 2015. Read the study
Dirty electricity is high frequency noise riding on a building’s wiring, often from power electronics. It is a newer area of research.
In three Minnesota schools, a single blind study reported improvements in teacher wellbeing and student behavior after high frequency noise on the wiring was reduced with filters.
What it means: Reducing electrical noise in a building may make a noticeable difference.
Havas M, Olstad A. Science of the Total Environment, 2008. Read the study
Among 137 teachers at a California school, 16 developed 18 cancers, a relative risk of 2.78. Cancer incidence correlated with high frequency voltage transient readings, while 60 Hz magnetic fields showed no association.
What it means: Dirty electricity can be measured separately from other fields, and researchers are studying it.
Milham S, Morgan LL. American Journal of Industrial Medicine, 2008. Read the study
Summaries are written by FieldWise in plain language. Click any study to read the original source. FieldWise reports what is measured in your space, compared to Building Biology SBM-2015 guidelines. It does not diagnose or treat any condition.
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