siegman@sierra.Stanford.EDU (Anthony E. Siegman) (07/13/89)
publish (LONG) Summary: Expires: References: <1681@neoucom.UUCP> <30010@ucbvax.BERKELEY.EDU> Sender: Reply-To: siegman@sierra.UUCP (Anthony E. Siegman) Followup-To: Distribution: Organization: Stanford University Keywords: radiation,elf,vlf,vdt news I genuinely admire Thom Gillespie's attempts to get at the hard data behind the recent New Yorker article on hazards of radiation from VDTs, for example by digging out copies of "VDT News"; and I wonder if he might be willing to dig for some further information on one specific aspect of this issue. TG says previous responses to his articles fall into two camps: Heavy VDT users, especially women, concerned about negative radiation effects, and blase younger respondents who perhaps feel themselves immortal (for a while, anyway) and aren't much concerned. There's a third group: Older, not blase but skeptical types (like myself), who've seen a lot of predictions of doom get hyped and then disappear (still have a copy of "The Coming Famine of 1975" on my bookshelf), and who are, not disbelieving, but definitely skeptical about the New Yorker article, until there's more, and much harder, evidence forthcoming. [Just to illustrate the attitude, if I can believe some of the scientific articles I read, many (most?) reputable and informed scientists (MRIS) think it's impossible to tell from the evidence at this point whether the Greenhouse Effect is going to cause global warming, or global cooling, or none of the above. MRIS conclude that, when you take all the evidence into account, the best current conclusion is that there has been absolutely NO measureable increase in the incidence of cancer that can be attributed to the widespread use of "toxic" chemicals that began around the turn of this century. Linus Pauling may be a great old guy, but Vitamin C for colds is nonsense. And so on. As my father was fond of saying, "Believe 20% of what you hear, 40% of what you read, and 60% of what you see with your own eyes."] To get to the point (this has drifted pretty far from comp.sys.mac.programmer), have we not already done a massive, world-wide, decades-long, literally hundreds of billions of test hours experiment on the possible _radiation_ effects of VDTs? -- it's called _television_ . We're talking the _radiation_ effects of VDTs here -- not the ergonomic, eye-strain, wrist-cramp, tendonitis effects. Aren't VDTs just specialized TV sets? Are there any really major technical differences (accelerating voltage, etc.) between the radiation-producing capabilities of VDTs and TVs. [And just saying you sit closer to a VDT than a TV set won't do. Ever see kids sitting 1 foot away from a giant TV screen? (and they're the ones that ought to damage easiest). And, it's probably solid angle that really ought to count, and solid angle from the observer subtended by a VDT or by a TV screen is typically about the same. And, TV screens are a lot bigger, often with bigger beam deflection angles, hence bigger electric and magnetic deflection fields.] So, what's the story here? TV is clearly bad for the brain (enough so in my opinion that I've raised 4 children without ever owning one). Is it bad for physical health also? If so, how come we've never seen any headlines about its radiation hazards? And, given the ubiquitous nature of TV, and the number of hours some people watch it, how come no one has noticed viewers dropping like flies? Does VDT News say anything on this?
amanda@intercon.uu.net (Amanda Walker) (07/13/89)
In article <203@sierra.stanford.edu>, siegman@sierra.Stanford.EDU (Anthony E. Siegman) writes: > Are there any really major technical > differences (accelerating voltage, etc.) between the > radiation-producing capabilities of VDTs and TVs. I can think of a couple things, but I have no idea whether or not they are significant. TVs are probably more likely to have color CRTs than VDTs (at least until recently). Modern VDTs use higher horizontal scan rates than TVs, which might require higher electron beam energies, although the phospors used might make a difference in how much energy is needed. Based on vague memories of high school physics :-), I'd think that color CRTs would be much more likely to emit dangerous radiation, since the electronic beams are (a) higher power, and (b) hitting a metal shadow mask. What do you get when you shoot electrons at a metal target? X-radiation... What I'd like to see is CRTs that are better shielded against *external* interference. I have a little fan on my desk to augment the A/C in our office, and I have to tilt it at just the right angle or my screen wobbles in synchrony :-). -- Amanda Walker InterCon Systems Corporation -- amanda@intercon.uu.net | ...!uunet!intercon!amanda