Air purifiers

The technical characteristics of air purifiers must be demonstrated with results from impartial testing, measuring clean air output x m3/h for 0.3 micron particles, any ozone generation, and sound levels with the device operating at various power levels. The purification efficiency of the air purifier must be at least 95% for 0.3 micron particles.

The sound level at the lowest power level in residential dwellings must be <33 dB, with purification room size of min.10 m2, corresponding to a clean air output of approximately 50 m3/h. The sound level in office environments at the lowest power level is a maximum of 35 dB. For devices intended for residential use the assumed room height for calculation purposes is 2.4 m, and the corresponding figure for office premises is 2.8 m (VTT 2.5 m2).

There is no human health-based limit value for ozone in indoor air. If there is a perceptible smell of ozone, the device generating it must be removed from the dwelling. For occupational exposure, the level regarded as harmful in Finland is a value of 0.05 pmm for an exposure duration of eight hours. Ozone occurs in the outdoor environment at all altitudes of the Earth’s atmosphere. Ozone in indoor air originates from outside and from devices operated indoors, such as electric air purifiers, laser printers and copying machines. Ozone gas is an upper respiratory tract irritant. In allergic individuals, ozone may aggravate the allergy symptoms. Ozone generation is therefore an essential criterion for air purifiers. The ozone generated by the device must be less than 0.05 ppm.