Why I Need to Keep Writing About Light Bulbs Instead of Something More Profound

I ran across this post the other day, while scrolling through some of the searches that have brought people to IA. It’s an example of why I’ve had to keep up my meager efforts to counteract factoids about compact fluorescent light bulbs. This individual was writing on the “American Thinker” blog, which from the other posts, apparently pulls quite a bit to the right politically. The post was pretty much the standard logic-deficient talking point from the right (mercury from CFLs is bad, therefore environmentalist positions on global climate change are bankrupt), but this time, ornamented with some really bad math:

A quick calculation shows that the 5 mg of mercury in an energy-conserving CFL is enough to fill an average size room (100 cubic meters volume) with the 0.05 mg/cubic meter vapor concentration that is considered hazardous for long term chronic exposure. Since this is the rule for laboratories, it probably does not account for people who might be especially sensitive, including infants, small children and pregnant women. As with allergies, different people can have vastly different responses to exposures to toxins.

The admonition to open the window for 15 minutes after a CFL break does not account for the various sizes / shapes of rooms, placement of windows (or absence thereof) and whether there is adequate cross-ventilation. And of course, it is not so convenient to ventilate a room thoroughly with outdoor air during the dead of winter in a northern clime.

Far be it from me to fuel a scare, but CFL backers are the global warming alarmists, after all, who have much less science to back up their claims for concern about climate change. It might be instructive to review the OSHA regulations concerning handling of mercury employed at CFL manufacturing plants. I bet the precautions are quite stringent.

No, no, no, no and no. Going back to the anecdote “all models are wrong, some are useful” (attributed to statistician George E.P. Box), the flaws in this particular model are: first, all of the mercury doesn’t volatilize in an instant, and second, it doesn’t volatilize into a hermetically sealed box. A few months back, I created an indoor air model of the concentrations in air you might expect if you broke a CFL in a room. It provides a more realistic depiction of the mass transfer of mercury from shimmering pinhead blob on the ground to vapor in air, and accounts, in a simple manner, typical air exchange in a room. I’m not going to insist this model is right, but EPA did calibrate it a bit using actual air monitoring data from other mercury spill situations (thermometers and ritual uses). And, I did obtain air concentrations thousands of times lower than American Thinker’s, which are not in the range considered hazardous for long-term chronic exposure. American Thinker’s cartoon depiction of indoor air modeling (no, strike that, my version is a cartoon depiction – his is a stick figure) reminds me of the IH classroom problem used to teach Ideal Gas Law calculations and dimensional analysis: “a 1-pound chlorine cylinder falls off a table in a closed 12 ft by 16 ft room with a 10 ft ceiling. The cylinder breaks and releases its contents instantaneously into the room. The air temperature is 77 degrees F. What is the chlorine concentration in air, in parts-per-million?” You don’t really use that kind of model for assessing exposures and health risks.

Guys, if you want to beat up “global warming alarmists”, just keep writing editorials. Please don’t try to inject facts into the discussion. You’ll only embarrass yourselves.