What are "Negative Ions"?
Negative ions are oxygen atoms with an extra electron. Ions are charged particles that are formed by nature when enough energy acts upon a molecule. An electron is ejected leaving a positively charged ion. The displaced electron attaches itself to a nearby molecule, which then becomes a negatively charged ion. In fresh country air it is common to find up to 4000 negative ions per cubic centimeter. By contrast, it is common to find that the number of negative ions in major cities at rush hour is less than 100.
What are the effects of negative ions?
They cause harmful microscopic-particles (particulates) in the air to clump together then weigh them down to the floor. Particulates include all forms of air pollution (smoke, chemical odors, carbon monoxide, bacteria, viruses and mold etc.). negative ions in the environment create a powerful antidote for many environmentally induced health problems such as allergies, respiratory ailments, headaches and infections.
What causes negative ion depletion?
Many factors contribute to the depletion of negative ions. Any high concentration of polluted, static, or hot/dry air causes this. Examples of specific culprits include:

* fluorescent lighting
* high concentration of electronic equipment
* static producing fibers
* air conditioners
* electric heaters and other heating systems
* many plastics
* older TVs and monitors (CRTs)
*airflow from furnace ducts and HVAC systems.
What size should an Ionic Crystal Lamp be to give the best results?
A rough rule of thumb is 1 pound for every square feet.
Here is what is recommended:

Room Size                 Size lamp
Cubicle/office               4-6 lbs.
10'x10'                          7-11 lbs.
10'x15'                        12-15 lbs.
10'x20'                         16-23 lbs.

For optimal results in large rooms, several lamps should be strategically placed throughout the room.
What therapeutic uses of crystal salt are there?
Speleotherapy is a therapy that is unique to caves and mines for treating respiratory illnesses. It was originated in Poland in the 1950's when it was noticed that salt miners rarely suffered from tuberculosis. It is common treatment in eastern and central Europe but almost unknown elsewhere.

The most well-known hub for speleotherapy  treatment is the Ukrainian Allergologic Hospital in Solotvyno. The hospital is located nearly 1,000 feet below the earth's surface in a former mine. Its staff reports a 90% effective rate in reducing asthma symptoms for up to three years.