Looking at formaldehyde first, it seems the higher the PG content, the more formaldehyde will be released. In the case of 50PG/50VG ratio and 100% PG, it seems the higher the voltage being outputted by your device, the higher the levels of formaldehyde will be released. For 100% VG, no formaldehyde is present. With acetaldehyde and acetone however is present in all three groups. With acetaldehyde 100% VG has the lowest level, then 50/50 ratio, than 100% PG. With acetone, 100% VG is still the lowest followed by 50/50 ratio and 100% PG similar to acetaldehyde; however unlike acetaldehyde it seems more acetone is released with the 50/50 ratio when voltage is increased, more than the 100% PG actually.

For two reasons.

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