Dear Umbra,

Here in Texas, where it is very hot in the summer (granted, we deserve to be in hell for having produced George Bush), some of us have been enthusiastically switching our light bulbs to cooler compact fluorescents. Is this a bad thing due to the mercury they contain?

Lisa
Smithville, Texas

Dearest Lisa,

Thanks for your question, as it will allow me to keep shedding light on the compact fluorescent issue. Compact fluorescent bulbs (CFLs) last far longer and use electricity more efficiently than conventional incandescent bulbs. Buy them if you can. They do contain a minuscule amount of mercury — roughly four milligrams, or an amount the size of the period at the end of this sentence. (By comparison, a watch battery can contain up to 25 milligrams of mercury.) Hence, when a compact fluorescent bulb has reached the end of its long life, you should, if possible, take it to a hazardous-waste disposal facility rather than dumping it in the trash.

That said, the mercury in compact fluorescent bulbs currently does not pose a major problem — and you know I don’t take pollutants lightly. In municipalities such as Grist’s hometown of Seattle, which is emphasizing conservation as a cost-cutting measure and pushing CFLs to the point of sending them free to ratepayers, there is an attendant concern about the solid-waste-disposal effects down the road. But let me emphasize: The tiny punctuation of mercury should not stop you from buying CFLs, any more than it stops you from wearing a watch.

One final note: Burning fossil fuels to generate electricity creates mercury pollution. Thus using compact fluorescent bulbs actually reduces mercury pollution, because CFLs use far less electricity than incandescent bulbs.

Lightly,
Umbra