Health claims of Salt Lamps

The claims made about the benefits of using a salt lamp are many. They range from reducing the need for an inhaler, to promoting happiness and wellbeing. Most of them seem to revolve around the idea that they purify the air.

How are they supposed to do that? They are just lamps after all. Is there some special property that makes them able to do that? Looking at the lamps themselves, and the marketing around them it seems it has something to do with heating up the salt.

Our favourite parody of a Doctor, Dr. Mehmet Oz mentions many ways in which salt lamps can be beneficial, but let's look at the claims made about air purification:

“When you purchase a lamp made out of Himalayan salt, it attracts the water and air pollutants in your home. The water will evaporate, thanks to the heat the lamp produces, and the allergens and dust that normally impact your health will get absorbed by the salt instead of being absorbed by your body.”

So he's saying salt can absorb dust? I'd like to see that. I'm not a chemist, but I'm pretty sure that's not a thing. I asked a friend who has a salt lamp to see if it was dusty at all. He said it wasn't. Not abig sample size though is it, and it might just be they are pretty good at dusting in their house.

In fact the claim made by most websites is that the lamps attract dust and pollutants from the air. So rather than absorbing it, they are like dust magnets.

How do they attract dust then? I found this website that said they were a kind of ionizer.

http://himalayansaltlampreview.com/

Salt lamps on sale at COSMIC in Christchurch

My favourite badly worded statement on this site is this:

”The benefit of ionizers is well known. While most ionizers on the market are man made machines, the salt crystal lamp is a beautiful alternative to mother nature, without any noise and No harmful Ozone.”

So how do Ionizers purify the air and what is an ion anyway?

An ion is an atom or molecule that has gained or lost an electron. Electrons are negatively charged, so if there are more electrons compared to protons, you get a negative ion. What do ionizers actually do? Ionizers have been designed to produce negative ions for their supposed desirable properties.

You can find negative ions in nature, in places like waterfalls and by crashing waves at the beach. They are also present in places with high levels of radioactivity like certain areas in the south of England.

Are ionizers good at air purifying?

Negative ions have been shown to attract dust particles into clumps, and once they are heavy enough, cause them to float down to a surface and stick. But, actual measurable benefits of ionizers have been shown to be negligible.

When an excess of ozone O3 was produced, this can be harmful for humans and animals, and even when negative ions do their job to attract particles in the air and cause them to stick to surfaces, they don't remove the particles, meaning, a fan in your room could just move them around again. If you are wanting to remove those particles from the air a HEPA (high-efficiency particulate air) filter would be a better option.

Are salt lamps ionizers?

For the answer to this question I turned to science communicator Derek Muller aka Veritasium. He has a growing YouTube channel devoted to science. He has been to Chernobyl to investigate fallout, to Australia to quiz the public on their science knowledge and the USA to hang out with science legend Bill Nye The Science Guy on his latest show ‘Bill Nye Saves the World'.

Derek decided to find out about claims around salt lamps, the studies on their efficacy, and finally the ionising properties of salt lamps, so he did what any good scientist would do, he took one to a lab.

At that lab was a device called a mass spectrometer, which is built to measure the mass-to-charge ratio of ions. Basically if you have a negatively charged molecule banging about, this machine will be able to tell you all about it.

So, did the machine monitor a spike in ionised particles when the lamp was turned on? No. In fact, no ionization was detected. At all.

So Dr. Oz, once again, it seems you're selling false promises based on pseudoscience.

So, if you're looking for a lamp that uses slightly more electricity than a usual lamp, that is warm to the touch and of a unique shape and texture, go no further than the salt lamp. However, if you are looking to purity the air, perhaps try a HEPA air filter instead.

References:

Dr. Oz on Salt Lamps: https://tinyurl.com/y3t5xlm9

Derek Muller on Salt Lamps: https://tinyurl.com/yy7fe6uo

Negative ions study: https://tinyurl.com/yxqelaa8

Wikipedia on Mass Spectrometry: https://tinyurl.com/zoalun9