Introduction to e-liquid
E-liquid is the fluid used in e-cigarettes. It is heated and evaporated into an inhalable vapor to provide nicotine, flavor, or both. E-liquid can be sold with or without nicotine depending on the legalities in the place of sale (or place of purchase) and also depending on the consumers needs.
E-liquids come in many variations, including different nicotine strengths and many different flavors (around 8000 on the market according to 2014 reports). The main ingredients are propylene glycol, vegetable glycerin, and flavorings; and most often, nicotine in liquid form. The liquid typically contains 80-95% propylene glycol and vegetable glycerin, and the remaining 5-20% being flavorings and nicotine. Among the most common ratios of vegetable glycerin and propylene glycol are 70-30 (VG-PG) and 80-20 (VG-PG). E-liquid containing vegetable glycerin and water or alcohol and made without propylene glycol are also sold.
Around 90% of e-liquids contain some level of nicotine. Unless clearly stated, it is uncertain whether the nicotine used in e-liquid is manufactured using a United States Pharmacopoeia (USP) grade nicotine, a tobacco plant extract, tobacco dust or a synthetic nicotine. Most e-cigarette liquids contain nicotine, but the level of nicotine varies depending on user-preference and manufacturers offerings. Although some e-juice is nicotine-free, surveys demonstrate that 97% of respondents use products that contain nicotine. A 2015 review suggests that 1% of users use liquid without nicotine, this is of course in jurisdictions where the sale and use of nicotine is allowed. To check on the laws in your area, look for your country page at vapetrotter.com.
Vapor produced by e-liquid
The vapor produced by eliquid can contain nicotine and usually contains vegetable glycerin, propylene glycol, flavors and aroma transporters. The nicotine level in the vapor varies among different products offered and is generally displayed on the label either in mg/ml or as a percentage. E-liquids without nicotine are also available.
A 2015 report on second-hand vapor commissioned by Public Health England concluded that e-cigarettes “release negligible levels of nicotine into ambient air”. The vapor may also contain tiny amounts of toxicants, carcinogens, and heavy metals, though in much less quantities than traditional cigarettes however, the peak concentration of nicotine delivered by e-cigarette use is comparable to that produced by conventional cigarette smoking.