Which Is More Harmful, E-Cigarettes or Cigarettes? A Chinese Academy of Sciences Genetics PhD Explai

Which is more harmful, e-cigarettes or cigarettes? The answer to this question is quite clear: from a harm perspective, e-cigarettes are significantly less harmful than traditional cigarettes. This is also one of the main reasons e-cigarettes were initially used as a substitute for traditional cigarettes to help with nicotine addiction, as the saying goes, "choose the lesser of two evils." So, some may ask why e-cigarettes are less harmful than traditional cigarettes?

There are two main differences between e-cigarettes and traditional cigarettes in terms of harm: the difference in tobacco components and the difference in vaporization, which I will elaborate on today.

1. From a component perspective, e-cigarettes are far less harmful than traditional cigarettes.

Tar

The greatest harm from traditional cigarettes comes from tar, which refers to the brown, greasy substance that accumulates in the cigarette filter during smoking, commonly known as cigarette oil. A very intuitive change during smoking is that the filter gradually darkens with each puff, and the fingers holding the cigarette also become discolored. Naturally, the teeth also become stained after smoking, and the root cause lies in tar.
 
Tar is not just about discoloration; it is actually a product of incomplete combustion of organic matter under low oxygen conditions, containing many harmful substances, including numerous carcinogens such as benzo[a]pyrene, cadmium, arsenic, beta-naphthylamine, nitrosamines, and phenolic compounds, as well as promoting carcinogenic substances like fumaric acid. For this reason, traditional tobacco has been classified as a Group 1 carcinogen by the International Agency for Research on Cancer under the World Health Organization, meaning it is definitively carcinogenic. Additionally, tar accelerates the aging of blood vessels in the human body, leading to vascular hardening and loss of elasticity, resulting in cardiovascular diseases. Many diseases are often caused by tar, which is why doctors often recommend quitting smoking as the first step for many conditions.

So, is tar unavoidable? The answer is basically yes; tar is unavoidable. Someone once gained recognition for reducing tar content in tobacco, but faced massive opposition, including hundreds of academicians who jointly wrote to the state requesting the cancellation of his qualifications. Yang Gonghuan, director of the Chinese Tobacco Control Office, stated that the "harm reduction and tar reduction" method for cigarettes is a deceptive scheme. Numerous studies, both domestic and international, have long shown that "low tar" does not equate to "low harm"; the concept of "harm reduction through low tar" is fundamentally flawed, and any results based on this premise are untenable. Moreover, low tar often leads to increased smoking rates among users, ultimately exacerbating harm.

So, do e-cigarettes contain tar? The answer is no; one of the biggest advantages of e-cigarettes is that they do not contain tar. Instead, they use safe VG (vegetable glycerin) and PG (propylene glycol) as substitutes, both of which are common organic solvents. You can find these ingredients in skincare products, and they are considered very safe components, with no sufficient evidence currently suggesting they are harmful.

Nicotine

Nicotine is another important component of tobacco and is well-known as a tobacco component. The physiological harm of nicotine itself is not as severe as that of tar, but nicotine has a troublesome issue: its addictive nature. Nicotine can lead to addiction, which is why smokers find it difficult to quit. In this regard, both e-cigarettes and traditional cigarettes contain nicotine. However, there are differences between the two; in traditional tobacco, nicotine is naturally secreted by the tobacco plant, making it very difficult to reduce nicotine content (since tobacco undergoes physical processing, nicotine does not decrease; if chemical methods are used to reduce nicotine, it will inevitably alter the flavor of the tobacco, affecting sales). In contrast, e-cigarettes can control the nicotine content since nicotine is added directly, even allowing for 0 nicotine options.

Of course, some may recall that during the recent 315 event, CCTV mentioned that e-cigarettes exceeded formaldehyde limits. I had previously written a rebuttal because CCTV's claim compared e-cigarettes to regular air. However, if we compare e-cigarettes to traditional tobacco, the answer remains that traditional tobacco is more harmful. In fact, the combustion of traditional tobacco itself generates high concentrations of formaldehyde, which makes the comparison somewhat misleading.
 
Moreover, the presence of formaldehyde is mainly due to substandard e-liquids. Currently, there are no national regulations for e-cigarettes, so when purchasing, one should choose brands that are recognized by many e-cigarette companies.
#p#分页标题#e#

In addition to the aforementioned chemical component differences, another significant difference between traditional cigarettes and e-cigarettes is the method of vaporization.

Combustion vs. Vaporization

We know that traditional cigarettes require combustion to be smoked, and this combustion process is also when a large number of harmful substances are generated. It is well-known that combustion is a chemical reaction process; traditional tobacco, when burned, produces a large number of substances. Since the combustion of tobacco is not uniform, the temperature varies greatly in different locations, leading to diverse chemical reaction conditions, which results in the generation of many harmful substances. This is one of the main factors contributing to the harm of tobacco.

In contrast, e-cigarettes do not combust; they simply heat and vaporize. Generally, e-cigarettes control the vaporization temperature between 250-350°C, with some e-cigarettes even achieving low-temperature vaporization at 220-250°C. This temperature is significantly lower than the 700-800°C of traditional tobacco, greatly reducing the harm of e-cigarettes and decreasing the generation of harmful substances, which is another key reason for the lower harm of e-cigarettes.
 
Additionally, the generation of particulate matter is also an important factor. In recent years, the impact of smog has made us more aware of environmental protection and health. We have learned about a substance called suspended particles, which can be very harmful, such as PM2.5, which refers to particles with a diameter around 2.5μm that can enter the body and cause serious harm, such as cardiovascular diseases. The combustion of traditional tobacco produces a large amount of solid suspended particulate matter. The following image shows the contribution of tobacco combustion to indoor particulate pollution, where we can see that after tobacco consumption, there is a tenfold increase in particles from PM1.0 to PM10, which are inhaled into the body and accumulate in the throat, trachea, and lungs, leading to irreversible diseases like throat cancer, tracheal cancer, and lung cancer over time.
 
In contrast, e-cigarettes can also produce particles during vaporization, but these are liquid particles that can be absorbed or expelled by the body. For example, the principle of nebulization used in clinical settings is based on this. Not only that, advancements in modern vaporization technology have improved the level of vaporization; for instance, the FEELM technology can achieve vaporization at 1μm, meaning the vapor produced does not contain particles in the PM1-PM10 range, thus avoiding solid particle damage to individuals.

Of course, the vaporization materials themselves also significantly affect the harmful substance emissions of e-cigarettes and the vaping experience. The following image shows the development history of e-cigarette vaporization technology, from cotton wicks, organic cotton, stainless steel mesh to the current porous ceramic heating elements.
 
The improvements in this area not only enhance the vaping experience itself (left image) but also reduce the release of harmful substances from e-cigarettes (right image). For example, porous ceramics have higher thermal conductivity, which can reduce vaporization time.
 
At this point, from an intuitive perspective, we can see that e-cigarettes are significantly less harmful than traditional cigarettes, reflected in:

1. Traditional cigarettes contain harmful tar, while e-cigarettes do not.

2. The nicotine content in traditional cigarettes is fixed and difficult to eliminate, while e-cigarettes can have adjustable nicotine levels, even allowing for 0 nicotine options.

3. The combustion of traditional cigarettes produces a large amount of non-decomposable solid particulate matter like PM2.5 that accumulates in the throat, trachea, and lungs, causing harm over time, while e-cigarettes produce liquid particles that can be absorbed or expelled by the body, essentially causing no particulate harm.

For these reasons, the emergence of e-cigarettes serves as a substitute for traditional cigarettes. The benefits include reducing the health damage caused by harmful substances like tar in traditional cigarettes for those unable to quit smoking; on the other hand, the controllable components of e-cigarettes allow for a gradual reduction in nicotine content, thereby alleviating dependence on nicotine and facilitating smoking cessation. Thus, they are used for smoking cessation purposes. #p#分页标题#e#

Which is more harmful, e-cigarettes or cigarettes? Ultimately, it should be noted that neither traditional tobacco nor e-cigarettes are harmless; it is merely a matter of choosing the lesser of two evils. Not smoking is the best option, and we must firmly prevent youth from smoking, even e-cigarettes.

This article is reprinted from Zhihu, with the answer by user Li Lei, and copyright belongs to the author. Commercial reproduction requires authorization from the author, while non-commercial reproduction must indicate the source.