What are vapes made of?

The electronic cigarette consists of two main parts: the hardware device and the filling liquid (vape oil). When the device heats the vape oil, a complex chemical aerosol is produced, which contains both the original components of the vape oil and new substances generated after heating.

 Components of the hardware device
The hardware of an electronic cigarette is usually made of various materials to ensure durability and conductivity.

Shell and frame: They are typically made of aluminum alloy, zinc alloy, or plastic (such as polycarbonate PC, ABS plastic).

Internal components: Connectors and support pieces may use chrome-plated brass to ensure conductivity. Heating coils are made of stainless steel, nickel-chromium alloys, etc.

Other materials: They may also include ceramics, silicone, and polytetrafluoroethylene (PTFE), etc.

Basic components of the vape oil (filling liquid)
The vape oil is the core of the electronic cigarette, and its basic formula is relatively simple, but the specific components vary by product.

Solvent carriers: Propylene glycol (PG) and vegetable glycerin (VG) are the two main components, accounting for more than 99% of the total vape oil. PG is thinner and can bring a "throat hit" similar to smoking and enhance the flavor; VG is more viscous and can produce a denser "smoke".

Active ingredients:

Nicotine: In nicotine electronic cigarettes, nicotine is the main addictive substance. It may exist in the form of free base or nicotine salt. Nicotine salt products often contain benzoic acid or lactic acid to lower the pH and make the taste smoother.

Cannabinoids: In cannabis electronic cigarettes, the active ingredients are tetrahydrocannabinol (THC) or cannabidiol (CBD).

Flavors: Used to provide various flavors, such as fruits, mint, desserts, etc. Common flavoring compounds include vanillin, ethyl maltol, and butyric acid ethyl ester, etc.

Other additives: May include water, ethanol, and trace amounts of preservatives or sweeteners.

New substances formed after heating: Heat-induced by-products
When the heating coil heats the vape oil to a high temperature (up to 157-266°C), the solvents and flavoring agents undergo thermal degradation, generating new harmful substances.

Aldehyde compounds: These are the main heat-induced by-products. PG and VG, when heated at high temperatures, will dehydrate to form formaldehyde, acetaldehyde, and propylaldehyde. The amount of propylaldehyde increases with the increase in the proportion of VG. These substances have strong irritation and toxicity to the respiratory tract.

Other by-products: The heating process may also produce compounds such as acetone.

☠️ Pollutants and illegal additives
In addition to the above components, the aerosol of electronic cigarettes may also contain pollutants from the device itself or illegal additives.

Metal particles: The heating coil may release tiny metal particles at high temperatures. Studies have found that all the detected electronic cigarette aerosols contain metal particles, including chromium (Cr), nickel (Ni), iron (Fe), lead (Pb), zinc (Zn), and even arsenic (As) and cadmium (Cd). It is notable that even FDA-authorized devices (such as Vuse Alto) have detected these metal particles in their aerosols. The size of these particles ranges from 14.21 to 281.3 nanometers.

Vitamin E acetate (VEA): This is a common additive in illegal cannabis electronic cigarettes and is used as a thickener. It has been clearly associated with the EVALI (Electronic Vape or Electronic Product Use-Related Lung Injury) epidemic that broke out in 2019. Studies have shown that inhaling VEA can cause acute lung injury and inflammatory responses.

In summary, the composition of an electronic cigarette is a complete chain from hardware materials to vape oil chemical components and to the complex aerosol mixture formed after heating. The aerosol contains not only the original components such as PG, VG, nicotine and flavoring agents, but also toxic substances such as aldehydes newly generated due to heating, as well as pollutants such as heavy metal particles and vitamin E acetate from the equipment or illegally added substances.