3. Plasma and catalyst

The presence of ozone and nitrogen oxides in the effluent leaving non-thermal plasma air treatment systems is the biggest drawback of this technology, which will require post-treatment to eliminate these toxic by-products, particularly ozone, whose output concentration can exceed 100 ppm(v) (i.e. 0.2 g/m ³ ). For the record, French labor regulations require a concentration of less than 0.2 ppm(v) for short-term exposure (STEL) and 0.1 ppm(v) for 8-hour exposure (TWA), while Europe recommends a limit value of less than 0.055 ppm(v).

In practice, ozone decomposes very rapidly at room temperature on a solid catalyst, which may be based on activated carbon, zeolite or manganese oxide (MnO ₂ ). The presence of ozone is the major drawback of systems using non-thermal plasma to treat...