Vaping is the act of inhaling an aerosol produced by an electronic device, which heats a liquid containing nicotine, flavorings, propylene glycol, and vegetable glycerin. Sub-ohm vaping significantly increases the power applied to the heating element, resulting in the production of massive vapor clouds. This method deviates sharply from traditional, low-power vaping and introduces distinct safety concerns related to device mechanics, chemical exposure, and nicotine delivery.
Defining High-Power Vaping Technology
Sub-ohm vaping is named for the coil’s electrical resistance, which is engineered to be below 1.0 ohm (Ω), often ranging from 0.1 to 0.5 ohms. This low resistance allows for the designation of “high-power” or “high-wattage” vaping, as standard devices operate above this threshold.
The fundamental principle is Ohm’s Law, where a lower resistance allows a greater electrical current to flow from the battery. Sub-ohm devices require a significantly higher power output, frequently operating between 50 watts (W) and 200W or more. This high power quickly generates intense heat within the coil, vaporizing the e-liquid at a much faster rate. The result is the characteristic massive vapor production that defines the sub-ohm experience.
Exposure to Thermal Decomposition Products
The primary health concern with high-power vaping is the chemical alteration of e-liquid components due to excessive heat, a process known as thermal decomposition. Propylene glycol (PG) and vegetable glycerin (VG) are the main base ingredients. While generally recognized as safe for ingestion, their stability changes dramatically when subjected to the high temperatures generated by sub-ohm coils.
Studies show that the generation of hazardous carbonyl compounds increases exponentially once the device’s power exceeds approximately 40W. The high heat fractures the PG and VG molecules, creating toxic byproducts that are then inhaled. Among these thermal degradation products are formaldehyde, acetaldehyde, and acrolein, all known irritants and potential toxins. Formaldehyde, for instance, has been detected in some high-power vaping aerosols at levels exceeding those found in traditional cigarette smoke.
Beyond the e-liquid bases, the coils themselves present a risk of heavy metal exposure, particularly under high-temperature conditions. The metallic alloys used in heating elements, which often contain nickel, chromium, and manganese, can degrade or leach into the e-liquid. This leaching is exacerbated by the high heat and the corrosive nature of certain e-liquid flavorings. Inhaling these metallic nanoparticles can lead to systemic exposure linked to respiratory and cardiovascular problems.
Battery Failure and Physical Safety
The massive power draw required for sub-ohm vaping necessitates the use of high-drain lithium-ion batteries, which introduce substantial physical safety risks when stressed or mishandled. These powerful cells, often the 18650 or 21700 formats, are capable of releasing energy rapidly. A malfunction can lead to thermal runaway, a chain reaction where increasing heat causes the battery’s temperature to rise uncontrollably.
Battery failure is frequently triggered by user error or poor maintenance. Short circuits can occur from using batteries with damaged wrappers, carrying loose batteries with metal objects like keys or coins, or exceeding the continuous discharge limit of the cell. Short circuits cause an immediate, massive current draw that quickly overheats the cell. This rapid overheating can cause the battery to vent hot gases and electrolyte, leading to fire or explosion. When these cylindrical batteries fail, they can be ejected from the device like a projectile, causing severe burns or trauma.
Rapid Nicotine Absorption
Sub-ohm vaping significantly impacts the efficiency of nicotine delivery, presenting a pharmacological concern. The high power output and resulting massive vapor production deliver a much greater volume of nicotine to the lungs with each puff compared to standard vaping devices. This leads to a faster and more concentrated absorption of nicotine into the bloodstream.
The high delivery rate means that users typically must use e-liquids with very low nicotine concentrations, often 3 milligrams per milliliter (mg/ml) or less, to avoid an overwhelming dose. If a user mistakenly uses a higher-strength liquid intended for a low-power device, the risk of acute nicotine poisoning is substantially increased. This rapid and potent delivery also has implications for the potential for nicotine addiction and the difficulty in managing or titrating one’s nicotine intake.