Do E-cigarettes Have Secondhand Smoke Harm, and How Are They Different from Cigarettes?

For friends who frequently use electronic cigarettes, you may often be asked whether electronic cigarettes pose secondhand smoke risks. Some may worry about their health. Although electronic cigarettes are already quite common abroad, many people in China are still unaware due to policy issues. Below, we will introduce the concept of smoke, whether electronic cigarettes have secondhand smoke risks, and the differences between electronic cigarette vapor and cigarette smoke.

Definition of Smoke

According to Wikipedia, smoke is defined as "a collection of solid and liquid particles and gases released into the air when a substance is burned or pyrolyzed, as well as the amount of air introduced or otherwise mixed into the mass."

Burning a substance greatly alters its chemical composition; smoke consists of visible carbon molecules, molecules of the burned substance, and other byproducts of combustion. In other words, igniting something produces many substances, many of which are hazardous when inhaled.

Definition of Vapor

According to Wikipedia, vapor is a substance in the gas phase below its critical temperature, meaning that vapor can condense into a liquid by increasing the pressure without lowering the temperature.

In other words, evaporating a liquid changes its state, but the vapor will consist of the same molecules as those in its liquid phase.

Technically, what we produce when we vaporize is not vapor but aerosol. Wikipedia defines aerosol as "tiny solid particles or liquid droplets suspended in air or other gases." After electronic liquid is vaporized, it becomes particles suspended in the air, which quickly settle to the ground. Because these particles are liquid rather than solid particles found in cigarette smoke, they do not pose the same risks to the lungs and cardiovascular system.

Since almost every vaper uses the term "vapor" instead of the scientifically accurate term "aerosol," we will continue to use "vapor," especially since the technical differences do not affect the points we are discussing.

What Are the Differences Between Smoke and Vapor?

Lighting a cigarette produces smoke, while vaporizing electronic liquid produces vapor (aerosol). Aside from their visual similarities, smoke and vapor have little in common. Their compositions are quite different, and they behave differently as well. Simply put, here are the distinctions between these substances.

Composition

When it comes to tobacco and electronic liquids, their only commonality is nicotine. Tobacco smoke contains thousands of chemicals, 70 of which are known carcinogens, and many more are unhealthy to inhale.

Although vapor does not produce water vapor, vaporized electronic liquids include vegetable glycerin, propylene glycol, nicotine, and food-grade flavorings. According to the CDC, aside from nicotine, any substance in electronic liquids can be safely consumed. The safety of inhalation has not been confirmed, but there are no known risks. Scientific research is still ongoing.

Odor

The smell of smoke lingers in a room for a long time, unlike vapor. Smokers may not notice this easily, but both smokers and non-smokers can identify this odor for hours after smoking.

Vapor clouds may be denser and dissipate more slowly—meaning they linger longer in a room—but the smell is generally more pleasant and dissipates more quickly.

Residue
Smoking in a room will eventually dirty fabrics, walls, and furniture. One of the main culprits is tar, a toxic resin mixture that makes smoking so deadly and notoriously stains everything it touches. Other combustion byproducts, such as carbon monoxide, work alongside tar to give your walls a dirty yellow hue.

In contrast, PG and VG in vapor may form a thin, hazy layer on glass surfaces, but it is easily cleaned. Over time, it will not yellow your walls or fabrics, nor will it make your furniture look older than it is.

Temperature

The temperature of burning coal is about 1112°F (600°C), while the temperature when inhaling a puff of smoke is about 1652°F (900°C). When smoke is inhaled and exhaled, it quickly reaches room temperature (mainstream smoke), while the smoke produced by the burning coal (sidestream smoke) raises the surrounding temperature, especially as the cigarette burns down.

Electronic cigarettes, on the other hand, vaporize electronic liquids at lower temperatures, typically not exceeding 482°F (200°C). Therefore, the exhaled vapor is much cooler than the surrounding air. Try exhaling onto your arm, and you will see for yourself.