When did air purifiers become popular??

In the mid-1980's air purifiers started to make their way into the residential market. Ozone air systems were widely used in the commercial restoration business for fire and flood damage to buildings. These applications utilized corona discharge systems (CD) that use a spark or electrically charged plates to simulate lightning. This converted the oxygen (O2) to ozone (O3). The CD method creates very high concentrated ozone. Plus by using air as the oxygen source, you are receiving 20% oxygen and 80% nitrogen. The problem with CD systems is with oxygen conversion you also get a nitrogen conversion, which makes nitric acid and nitric oxide.