Recently a reader suggested I cover the topic of Himalayan salt crystal lamps. I have a bit of personal experience since, gasp, I own one. I first encountered these on a trip to Asheville in a small kitschy shop. I thought that it looked cool and asked the owner how much it cost. I was a bit surprised when he informed me that since it purified the air, increased my chi, realigned my chakra, and would wash my dog for me (I kid!), it was $40.
Not falling for that, sorry.
Someone saw the look in my eyes and pulled me away before I could discuss the finer points of inorganic chemistry with the shopkeeper.
They can’t pull me away from blogging so here I go:
Himalayan salt crystal lamps supposedly work through releasing ions (usually positive ones because they are good! but sometimes negative ones because … ???) to purify the air through an undisclosed mechanism. They do this without being reduced in mass or volume despite working for years. The only necessary mechanism for action is a lightbulb or candle. I did end up buying one for $10 from a rock store because, hey, they are pretty. No, it doesn’t do anything. If you want a cheap one for decoration, here’s one. Try to find my post there. Anyway….
Let’s debunk this from top-down and bottom-up.
First of all, it’s not releasing ions. Sorry. If you dissolved it in water to form an aqueous solution, you’d create Sodium and Chloride ions as the salt crystals break down. That’s the best way to get ions from salt. Heating the salt won’t really do anything interesting unless you’re melting it.. which we’re not. The lamps are never reduced in size despite the statement that they’re releasing ions constantly. Regardless of all of that, melting the salt won’t cause ions to fly out and scrub your air anyway… not that ions would do that.
That brings me to my next point to consider: ionic air filters don’t really clean the air. Even the $400 ionic filters don’t really do that much. Some dust gets attracted to their plates but it really doesn’t work that well since the dirtier the capacitive plates get, the less effective they are. Since the whole point of the capacitive plates is to attract dust, you can quickly see the problem. Also, those ionic filters release ozone which is bad for you. Generally, you could assume that those things do more harm than good.
Coming back around to Himalayan salt crystal lamps, we have something that doesn’t actually do the mechanism of action that it says it does whenever that mechanism doesn’t actually do very much even if it did work. At least they’re pretty.