Answer to Question #4225 Submitted to "Ask the Experts"

The following question was answered by an expert in the appropriate field:

I have a small 10.6"-wide computer laptop. If I have it on my lap for about 10 minutes or so, I get a bit of a nauseating sensation. It's not the heat that bothers me, it's almost the same sensation that I get after getting an x ray from the dentist's office. Government laws and such are there to assure minimal harmful emissions. My laptop's manufacturer denies any kind of harmful emissions and simply says it's the heat causing my problem. Could the lithium battery of the unit be leaking emissions and causing my nausea?

I am aware of no technical reasons for your seeming sensitivity in the situations that you describe. Laptop computers do not use CRT displays and do not emit ionizing radiation (x rays). The radiofrequency radiations that are emitted are restricted to what are believed to be harmless levels. Some laptop manufacturers warn against keeping the computer on your lap for extended periods because of the sometimes significant heat generation. You do not seem to feel the heat so that probably is not a factor in how you feel. Depending on how sensitive you might be to mechanical vibrations, it is possible that CD and/or hard drive activity could be sensed, although I would not expect such to produce nausea. To my knowledge, the lithium battery would produce no sensible emissions.

If you have not already checked out previous questions and answers related to emissions from computers and TVs available at the HPS Ask the Experts Web site you may want to do this.

Human beings exhibit considerable variability in their sensitivity to many physical agents that are part of our environment, and our best judgments regarding such sensitivity are based on available information from scientific studies. Such information forms the basis for the standards that we use in controlling exposure to a variety of possibly harmful agents. In general, such standards incorporate conservative safety factors that account for what are felt to be degrees of variability in human sensitivity. Since all studies of exposure to agents of concern are necessarily restricted to selected groups of individuals, it is always possible that there may exist some other individual(s) who may exhibit a degree and/or type of sensitivity beyond what is observed in studies and what is embodied in the governing standards that we adopt. So, regarding your described sensitivity to your laptop, we cannot say that you are not sensing something that most of the rest of us are unable to sense, only that, based on our current knowledge, we would not expect the emissions from either the laptop or a distant TV to be perceptible or harmful.

Addendum: A visitor to this site suffered a similar plight to yours and wrote to us to suggest that the cause of your ill feeling could be from screen-scrolling that might affect the eye-inner-ear connection and produce a feeling of nausea-the effect being similar to motion sickness. She noted that the reduced screen size of the laptop results in more frequent scrolling and using the page-down key rather than scrolling may reduce the effect. She also provided a link to another site, Ask MetaFilter, that tosses around some ideas on the laptop-induced nausea.

George Chabot, PhD, CHP

Answer posted on February 9, 2005. The information and material posted on this Web site is intended as general reference information only. Specific facts and circumstances may alter the concepts and applications of materials and information described herein. The information provided is not a substitute for professional advice and should not be relied upon in the absence of such professional advice specific to whatever facts and circumstances are presented in any given situation. Answers are correct at the time they are posted on the Web site. Be advised that over time, some requirements could change, new data could be made available, or Internet links could change. For answers that have been posted for several months or longer, please check the current status of the posted information prior to using the responses for specific applications.