Let's look at some of these uses. Factories use static electricity to reduce pollution coming from their smokestacks. They give the smoke an electric charge. When it passes by an electrode of the opposite charge, most of the smoke particles cling to the electrode. This keeps the pollution from going out into the atmosphere.
Some people purchase what are called air ionizers to freshen and purify the air in their homes.
They work on a similar principle as the smokestack pollution control. These devices strip electrons from smoke molecules, dust particles, and pollen in the air, just as what happens in creating static electricity. These charged dust and smoke particles are then attracted to and stick to a plate on the device with the opposite charge. After a while, much of the pollution is drawn from the air. Since charged particles will also stick to neutral surfaces, some of them can stick to the wall near the ionizer, making it very dirty and difficult to clean.