Fogging of car windows by volatile organic compounds (VOC) evaporating from car plastics

Condensation of the VOC vaporizing from car interior plastics and fogging of the car panes has been described. The reflection and gravimetric methods (DIN 75201) for measuring the fogging effect are summarized. The origin of the light scattering films on car window glass surfaces has been identified, involving the VOC polymer matrices like PVC plasticizers and PUR foam flame retardants, occasionally as hot as 110 degrees C. Emission of VOCs from cloth upholstery has been discussed, too. The relation between the plasticizer's molecular structure and its tendency of fogging has been discussed in view of the limited number of eligible plasticizer types. Volkswagen Group's program, known to effectively cut fogging down to 5% by some car parts (e.g. dashboard), has identified several condensate constituents, released by phthalate-type plasticizers, in the condensates sampled in normally operated and in lab-tested cars. Trichloropropyl phosphate proved to be a typical PUR flame-retardant VOC; amines proved to have been emitted, too. Cations like Ca2+ and NH4+ and anions like Cl-, SO42- and CO32- were also detected in the condensates. Textile finish preparations were found to emit oligomers, paraffins and fatty acid esters. De-fogging processes have been mentioned, too.