A study published in the November issue of Environmental Health Perspectives revealed that ozone air purifiers for commercial and residential use that are sold to remove secondhand (SHS) cigarette smoke toxics from indoor air and thus improve its quality could be having exactly the opposite effect. SHS contains at least 250 known toxicants, but until this study little was known about what is formed when SHS molecules react with ozone. Highly reactive ozone is a pervasive outdoor pollutant. It also is purposely produced indoors by certain air-purifying devices, ostensibly to remove airborne toxicants and odors like those from cigarette smoking. However, they found that when the molecules in SHS react with ozone they can make ultrafine particles detrimental to lung health. To view the study click here.