Answer to Question #122 Submitted to "Ask the Experts"

Q

How much radiation does a 20" color monitor emit? (We have eight in one work area.) How far apart should each work station be?

A

An excellent discussion of ionizing radiation emitted from televisions can be found at the We Want You to Know About Television Radiation Web site. This is the Web site for the Center for Devices and Radiological Health (CDRH), a division of the Food and Drug Administration (FDA). The FDA/CDRH is the federal agency charged with setting and regulating radiation emitted by electronic products, like TVs and color monitors. Although the information page is written about TVs, all the information is directly applicable to color monitors also. To answer your specific question I will first address the requirements for ionizing radiation emissions from color monitors and then address the reality. As stated at the CDRH Web site, all TVs (and color monitors) are required to demonstrate they do not exceed a rate of radiation exposure of 0.5 milliroentgens per hour anywhere around the monitor under the most adverse operating conditions. The FDA requires manufacturers to routinely test for x rays and the FDA tests a few products each year to check on the manufacturers' compliance with these requirements. This standard is the maximum exposure rate that can exist at a distance of 5 centimeters, or about 2 inches, from the monitor. This exposure rate is very low. For perspective, this is about the same rate of exposure a person receives from cosmic radiation when flying in a commercial airplane. Because the ionizing radiation that may be emitted from color monitors is very low-energy x rays, if radiation did exist at the maximum standard at 2 inches from the monitor it would be attenuated (reduced) to a small fraction of that rate at the closest viewing distance of about 15 inches. In reality, the CDRH states that “it should be emphasized, however, that most TV sets have been found not to give off any measurable level of radiation” and that “There should be no health hazard in watching TV at a distance at which the image quality is satisfactory to the viewer.” Because there is, in reality, no measurable ionizing radiation from present-day color monitors, there is no reason to be concerned about the number of monitors in a given area. If further information is desired, questions can be addressed to the FDA/CDRH at 301-594-4654. Keith H. Dinger, CHP Past President, HPS