The lamps with a bulb inside, when lit and warming up emit negative ions, which is a function of attracting humidity from the air, and then neutralizing the positive ions found in the air of our living spaces as well as generating additional negative ion content, a very healthy, invigorating condition by also purifying the air. The colour of the lamp is pink and very soothing and calming down your nerves for relaxation.
The larger the HCS lamp's surface, the more negative ions can be thrown off.