Does anyone know what is the influence of temperature in the break down of PG into formaldehyde? Apparently there is also a process for VG to turn into formaldehyde, but it may be different. (oxidation or hydrolysis of glycerin?). The questions arise from the recent studies that detected formaldehyde in e-cigs but with big variations between e-cig brands. It would be important to determine the important factors in the generation of formaldehyde so better design choices could be made. Formaldehyde is definitely something that should be avoided as much as possible.