How are gravimetric analyses of particulate matter performed, in order to determine particulate matter concentration in air?

I've been surfing Google Scholar a bit and learned that a common and comparatively less expensive method of measuring particulate matter concentration in air was analysis through gravimetric methods. I was wondering, what sort of materials are used to filter the particulate matter from the air, in an indoor setting, for particles of diameter 2.5 μm? And does the technique consist of measuring the weight difference between a clean vs. used filter? Any reading recommendations would be highly appreciated!


