Warning, the study quoted below found various toxic chemicals being released from PG and VG. Some of them are carcinogenic.
Quote:Use of electronic cigarettes has grown exponentially over the past few years, raising concerns about harmful emissions. This study quantified potentially toxic compounds in the vapor and identified key parameters affecting emissions. Six principal constituents in three different refill “e-liquids” were propylene glycol (PG), glycerin, nicotine, ethanol, acetol, and propylene oxide. The latter, with mass concentrations of 0.4–0.6%, is a possible carcinogen and respiratory irritant. Aerosols generated with vaporizers contained up to 31 compounds, including nicotine, nicotyrine, formaldehyde, acetaldehyde, glycidol, acrolein, acetol, and diacetyl. Glycidol is a probable carcinogen not previously identified in the vapor, and acrolein is a powerful irritant. Emission rates ranged from tens to thousands of nanograms of toxicants per milligram of e-liquid vaporized, and they were significantly higher for a single-coil vs a double-coil vaporizer (by up to an order of magnitude for aldehydes). By increasing the voltage applied to a single-coil device from 3.3 to 4.8 V, the mass of e-liquid consumed doubled from 3.7 to 7.5 mg puff–1 and the total aldehyde emission rates tripled from 53 to 165 μg puff–1, with acrolein rates growing by a factor of 10. Aldehyde emissions increased by more than 60% after the device was reused several times, likely due to the buildup of polymerization byproducts that degraded upon heating. These findings suggest that thermal degradation byproducts are formed during vapor generation. Glycidol and acrolein were primarily produced by glycerin degradation. Acetol and 2-propen-1-ol were produced mostly from PG, while other compounds (e.g., formaldehyde) originated from both. Because emissions originate from reaction of the most common e-liquid constituents (solvents), harmful emissions are expected to be ubiquitous when e-cigarette vapor is present.
Source:
http://pubs.acs.org/doi/.../10.1021/acs.est.6b01741Many of these chemicals are major health hazards:
DiacetylQuote:Diacetyl has been linked to a rare type of lung disease, bronchiolitis obliterans, also called "popcorn worker's lung" because it has been seen primarily in workers at microwave popcorn factories. This disease destroys the lungs and can be cured only by a lung transplant. Diacetyl appears to damage lungs when it is repeatedly inhaled in vaporized form (!!!).
Source:
http://www.drweil.com/dr...wave-Popcorn-Threat.htmlGlycidolProbable carcinogen not previously identified in e-vapor
Propylene oxideProbable carcinogen and respiratory irritant
AcetaldehydeCarcinogen (nasal, oral)
AcroleinPowerful irritant
FormaldehydeKnown carcinogen. Causes nasal sinus cancer, nasopharyngeal cancer and leukemia:
Quote:Ingestion of 30 mL of a solution containing 37% formaldehyde has been reported to cause death in an adult human. Water solution of formaldehyde is very corrosive and its ingestion can cause severe injury to the upper gastrointestinal tract.
Further information and evaluation of all known data led the IARC to reclassify formaldehyde as a known human carcinogen associated with nasal sinus cancer and nasopharyngeal cancer. Recent studies have also shown a positive correlation between exposure to formaldehyde and the development of leukemia, particularly myeloid leukemia.
Source:
https://en.wikipedia.org/wiki/FormaldehydeBelow another paper. It shows that e-sigs release Formaldehyde. No Formaldehyde is found at regular e-cigarettes power levels. However, at more volt (more power, higher coil temp) a significant increase of Formaldehyde was detected. This is bad news for sub-ohm vaping. As commercial sub-ohm vapes are a relatively new phenomenon, the question is if the Formaldehyde factor is an overlooked danger up to now.
Quote:Formaldehyde is a known degradation product of propylene glycol that reacts with propylene glycol and glycerol during vaporization to produce hemiacetals. These molecules are known formaldehyde-releasing agents. In many samples of the particulate matter (i.e., the aerosol) in “vaped” e-cigarettes, more than 2% of the total solvent molecules have converted to formaldehyde-releasing agents, reaching concentrations higher than concentrations of nicotine. This happens when propylene glycol and glycerol are heated in the presence of oxygen to temperatures reached by commercially available e-cigarettes operating at high voltage. How formaldehyde-releasing agents behave in the respiratory tract is unknown, but formaldehyde is an International Agency for Research on Cancer group 1 carcinogen.
Here we present results of an analysis of commercial e-liquid vaporized with the use of a “tank system” e-cigarette featuring a variable-voltage battery. The aerosolized liquid was collected in an NMR spectroscopy tube (10 50-ml puffs over 5 minutes; 3 to 4 seconds per puff). With each puff, 5 to 11 mg of e-liquid was consumed, and 2 to 6 mg of liquid was collected. At low voltage (3.3 V), we did not detect the formation of any formaldehyde-releasing agents (estimated limit of detection, approximately 0.1 μg per 10 puffs). At high voltage (5.0 V), a mean (±SE) of 380±90 μg per sample (10 puffs) of formaldehyde was detected as formaldehyde-releasing agents. Extrapolating from the results at high voltage, an e-cigarette user vaping at a rate of 3 ml per day would inhale 14.4±3.3 mg of formaldehyde per day in formaldehyde-releasing agents. This estimate is conservative because we did not collect all of the aerosolized liquid, nor did we collect any gas-phase formaldehyde. One estimate of the average delivery of formaldehyde from conventional cigarettes is approximately 150 μg per cigarette,3 or 3 mg per pack of 20 cigarettes.
Source:
http://www.nejm.org/doi/...6/NEJMc1413069#t=article14mg Formaldehyde per 3 ml. If DMT 1:4 (250mg DMT per 1ml), then per 30 mg DMT = (14/3) / (250/30) = 0.6mg Formaldehyde = same as 4 sigarettes. This is not much. However, the question is how accurate the 14mg per 3ml estimation is. What if it's 10x more at high vape rates? Sub-ohm vaping has not been researched well enough yet. I would keep the DMT ratio as high as possible so as little as possible vapor is needed.
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