With the use of filters, more and more particles are trapped in dust and fibers, and the air flow is further restricted. First of all, it’s good for you, because there’s less room for particles to pass through. However, this eventually blocks the air flow and prevents particles from entering the filter completely. At this point, you need to clean or change the filter, depending on the type of filter. If there is not enough air flow through the filter, the particles will not enter the filter, become entangled in the fiber and remain in the air.