Workplaces get constant movement from people, equipment, and materials. Every time the doors open, microscopic particles of dust and allergens come inside. Chemical-based cleaners, printers, and other types of office equipment also release toxic substances into the air. These keep getting recycled and flowing through the same space.
In places where windows remain closed, the AC air filter becomes the main source of protection from pollutants. However, these filters only capture larger dust particles, failing to stop microscopic pollutants from causing harm.