This is the HEPASilent SmokeStop replacement filter for all air purifiers in the Blueair 500 Series, such as the 501, 502, 503 and 550E.
The Blueair 500 Series SmokeStop filter uses Blueair’s patented HEPASilent technology. This filtration technology is a combination of mechanical and electrostatic filtration, and allows the Blueair 500 Series air purifiers to deliver more clean air at a faster rate with less noise.

The Blueair 500 Series SmokeStop filter is a Three-Stage Progressive Filter – a filter that resembles having many filters in one.
The filter is made up out of three different levels of millions of ultra-thin fibres, and with its ‘lock-in’ design, once captured the particles are not re-released back into your environment, even when the filter is heavily loaded.
The first layers capture larger particles like pollen and dust, and the later layers capture smaller particles like bacteria and exhaust particles.
The 500 Series SmokeStop filter kit includes three filters with enhanced active carbon; one for each side that clean air is released from the unit.
Regular filters are thinner and mostly consist of the same fibre size and material throughout, this leads to them clogging up sooner. However, the unique design of the Blueair 500 Series Three-Stage Progressive Filter resists clogging and allows the Blueair 500 Series air purifiers to perform longer on their peak performance.
The 500 Series SmokeStop Filter includes 0.9kg of activated carbon for odour and gas filtration. This removes gaseous pollutants such as cigarette and cigar smoke, or other VOCs (Volatile Organic Compounds) such as household paints.