Models with the DS and DXS designation are designed for smoke including wildfire smoke, tobacco and other smoking products. Smoke presents a unique air quality challenge. The complex mix of fine particles, widely ranging chemicals (depending on what’s burning) and penetrating odor requires a special air purifier. Units in the DS and DXS range come with a tar-trapping filter which traps sticky pollutants that would otherwise clog the main filters. DS and DXS models also come with a special carbon blend to better attract and trap smoke chemicals and odors. DXS is the largest of the smoking filters, while the DS is ideal for moderate levels of smoke.