In general, an air cleaner works by first filtering the air through a tight mesh filter, which allows air to pass yet captures dust, hair, and spores, and then passes it to the central air and heating system. More advanced air cleaners use the filter method alongside an ionized grid, which uses electricity to draw particulate matter in the air to the grid, which is easily cleaned under running water. In the most advanced models, the filter and ionized grid work in tandem with an ultraviolet system to kill harmful bacteria and viruses that may get past the first two steps.