Alliance for Lighting Information

Health Effects from Lighting

by David M. Keith

Health effects from lighting cover a very broad range, from the physio-biologic effects of radiation to the effects of pollution associated with lighting.

Certainly the pollution from generation of electricity is part of the effects from lighting, and mercury is a neurotoxin that is released into the environment, principally from coal-fueled power plants. Mercury is also present in metal halide and fluorescent lamps, which may be hazardous waste and should be disposed or recycled accordingly.

Metal halide lamps have in the past been associated with "non-pasive end-of-life" which is another way of saying they can explode, which is a health hazard. An associated hazard is the potential for eye or skin damage from direct exposure to ultraviolet radiation from metal halide lamps that have broken or missing glass envelopes.

Seasonal affective disorder (SAD) is a condition that has been treated using light exposure in suitable spectra, intensity and duration, e.g. 10,000 lx from "daylight" fluorescent lamps for an hour, to change mood and physical health. Similar treatment has been recommended for recovering from "jet-lag" through the "resetting of the diurnal cycle" that is associated with the hormone melatonin and responds to light exposure.

Since 2002, information has been developed about the role of retinal ganglion cells in the control of melatonin. Dr. Pauley's summary of the science as of 2004 is available from Medical Hypotheses (v63i4 Pages 588-596). A brief summary of the information is available here.

Another form of pollution associated with lighting is skyglow, the uplight that is reflected by the atmosphere back to the ground. Such atmospheric reflection is very dependent on the spectral power distribution of the radiation. The relative effects from different sources can be estimated by the Rayleigh Scatter Index (RSI). With the potential that many life forms' diurnal cycle is sensitive to radiation in the same way we are, the interaction of atmospheric scattering and melanopsin may be important. A summary of the RSI evaluation of sources - including "melanoptic" sensitivity - is here.

Additional Links

LIGHT, ENDOCRINE SYSTEMS AND CANCER: Facts and Research Perspectives

from International Symposium May 2–3, 2002 University of Cologne, Germany and NEUROENDOCRINOLOGY LETTERS.

Mercury Content of HID Lamps

Mercury Pollution from Lamps

Mercury Pollution from Power Generation

Mercury Pollution Summary

Study: Melatonin Stops Light-at-night Breast Cancer Burden

is a press release from NEUROENDOCRINOLOGY LETTERS.

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