Himalayan salt lamps emit negative ions. The bulb inside of the lamp heats the crystal and supports the ionizing effect. Salt itself is hygroscopicand attracts the water from the surroundings. You can often see that the salt lamp is damp or even wet, especially in more humid environments. Due to the gentle heat of the lamp, the water quickly evaporates and during the evaporation process the beneficial negative ions get created. They go on to bind with excessive positive ions (bacteria, molds and allergens all carry a positive charge) and neutralize the electronic smog in your home.