The anatomy and physiology of vapes: Mods

Second of a two-part special report


Read Part 1 here.

When Jess* first tried to quit smoking, she turned to mod vapes. She had been using cigarettes for some four to five years, and found that it was wearing pretty heavily on her lungs and on her wallet. She had tried vaping before, but never had a device of her own; instead, she just shared with her friends here and there. Perhaps, she thought, it was time for her to get one for herself.

Her first rig was a Joyetech Cuboid that she bought off of someone, and used it with an Avocado 24 atomizer. But before long, she found its upkeep too cumbersome, and sold it off.

She tried juuling for a while, but once again found that it wasn’t cost-effective enough to put up with. She’d go through one e-juice cartridge in a week, tops, and finish an entire box in under a month. This typically her back by easily more than a thousand pesos.

Currently, she’s using a different pod mod device, which gives her a good middle ground between affordability and aesthetic. Sure, she now needs to carry around a bulkier vape, but she also gets to puff out bigger, more impressive clouds, something that wasn’t possible with her JUUL pen.

Despite this, Jess also admits that she’s seen what the pod mod has to offer, bought it, and has now grown tired of it. “I want to try mods again,” she says, “you have control over your coil and cotton.”

She also has some frustration over the pre-filled cartridges. “Some juices can get too strong and it hurts the throat,” she said. “I can’t even taste the flavor anymore.” She wants control over this, too, so Jess says she’s ready to jump right back into the belly of the box mod.

Unlike pods, mods are unapologetically, more obviously complex.

Modifiability over discreetness: What are mods?

Box mods are fairly recent additions to the e-cigarette family, only a generation older than pod systems. Unlike pods, though, mods are unapologetically, more obviously complex. They are generally larger than the stealthy pods, typified by a bulky, heavy body and a long neck leading to the mouthpiece.

The flip side of this complexity is that it gives the user much more control over each hit. (“Mod” is shorthand for modifiable, which points to how adaptable the system is to user preferences.) For vapers who are more particular about how the aerosols taste, or how much they take in with each breath, or how big the clouds they produce are, learning the intricacies of building and operating a box mod vape may be worthwhile.

The body (which some also call a mod) holds and regulates the entire system’s power; its bulk is a direct consequence of this. Unlike pod systems, box mods use larger, more powerful batteries. Most common of these are 18650 batteries, which are rechargeable and about as strong as three AA batteries in series.

On their own, mods are useless: They only bring the power, and so they need something to power up. Atomizers assume this role, acting very similarly to the pod cartridge.

Method of delivery: How do mods work?

Barring a stronger battery and a more elaborate overall structure, mod vapes work pretty much the same way pods do. When fired up―by pressing a button, instead of just automatically activated through inhalation―the battery sends ions up and through a metallic conduit that connects the atomizer to the main body.

The path that the electrons take is maybe a bit longer, but this ultimately also heats up the coil, which then evaporates the e-juice. Breathing in through the mouth piece scoops the aerosols up, drawing them straight into the lungs.

Unlike pods, though, mod systems give the user more freedom over the current flowing through the device and, by extension, control over the vaping experience. There are two main ways this can happen. Some devices allow the vaper to tweak the voltage setting. This pertains to the force with which the electrons are pushed from the battery and throughout the entire rig.

Cutting out the science, this becomes much easier in practice: Higher voltage makes for a hotter coil and a stronger hit.

But the more involved vaper will know that the equation is a bit more complicated. How hot a coil gets is a function both of the voltage setting and of the coil’s resistance. Even if the user cranks the voltage up, an impossibly resistive coil will likely only feel toasty.

To make this even simpler, other devices take out the math. Instead of giving the user rein over voltage, they allow control over power, or wattage. Once set, this variable remains constant regardless of the vape’s build. Ten watts in one brand will still be ten watts in another; a 54-watt output using a thick, nichrome coil will stay the same when switching to a Kanthal coil or a finer coil.

“Wattage is directly related to heat,” Jess explains. “The really high-end mods can reach up to 200 W.” Her vape now has a 40-W ceiling, which she thinks is part of why she hasn’t been able to produce impressive plumes of vapor.

The one indispensable thing that all box mods―and all vapes in general―share is the need for e-juice. What good is a decked-out rig for if there’s nothing to aerosolize?

Modification of devices: Mod vape hardware options

This degree of adaptability is evident in the staggering diversity of mod vape hardware. There are dozens―if not much, much more―of choices for a rig body and atomizer. Different brands come out with different lines, each with many different models and builds.

There are, for example, atomizers that come with prebuilt heating coils that vapers just need to replace once burnt out. Others yield even more control to the user, allowing them to assemble their own coil-and-wick setup.

In turn, this opens up layers upon layers of customization possibilities. Some coils are more resistive, have more turns, and are longer than others; some look like typical coils, while other come in mesh form. Wicks come in different materials. Some atomizers come with a tank, while others don’t. Mouthpiece barrels have different allowances for airflow.

The one indispensable thing that all box mods―and all vapes in general―share is the need for e-juice. What good is a decked-out rig for if there’s nothing to aerosolize?

But juices themselves are very diverse. Fundamentally, e-juices will contain some ratio of organic solvents that liquefy nicotine and carry it in the aerosols. Many different solvents can fill this role, but the most popular ones are propylene glycol and vegetable glycerin.

To add yet another layer to this variety, juices also come in many different flavors: tobacco; menthol; fruity, like mango and strawberry; and dessert, like cheesecake and cinnamon. Already, over 15,000 flavors had been documented as early as 2014, and the playing field was expanding by some 200 new flavors per month.

In a lot of ways, the market of mod vapes resembles the landscape of smartphones. The sheer number of options is daunting and overwhelming, but can also become intoxicating.

“People have different needs,” Jess says. “For people who are just after high nicotine content, the small pods would be their best bet. The big mods and atomizers, usually those are for cloud chasers.”

Though still such a very young phenomenon, there is already a substantial body of literature suggesting harms associated with vaping.

Manifestations of danger: What are the risks of using mods?

The dizzying variety of mod vapes shouldn’t distract from the often-underplayed risks they come with, though.

“They’ve been associated with explosions and poisoning,” says Dr Riz Gonzalez, MD, Chairwoman of the Tobacco Control Advocacy Group of the Philippine Pediatric Society, referring to mod vapes.

Mods need regular maintenance and cleaning, particularly in its internal workings, she continues. Neglecting to do so might cause a short circuit and lead to an explosion. This may also be the case when the vape, particularly the battery, is exposed to moisture or extreme temperatures, or when improperly charged. (It is worth noting, though, that explosions have become increasingly rare, especially with the newer mods that have built-in safety features).

The coils themselves are cause for concern. During heating, they leach metallic nanoparticles into the juice, Dr Gonzalez said, “and these are irritants.” Several studies, indeed, have found considerable levels of metals such as aluminum, nickel, lead, copper, iron, tin, and zinc in the e-juice. And they don’t just stay there. When the juice evaporates, it carries these tiny nanoparticles in the aerosols.

“The microparticles float in the aerosols, and when you inhale, they go into the lungs, and lungs are only meant to inhale clean air,” Dr Gonzalez explains. “Anything beyond what is needed by the body, the body reacts to through inflammatory processes.”

In the same way that the body tries to clot up a wound, it floods the lungs with platelets, fibrin, thrombin, and other coagulants in response to these metallic invaders. “This blocks the airways. It’s the same thing that happens with EVALI,” she adds, referring to the e-cigarette-related lung injury epidemic that took the US by storm late last year.

This goes for e-juices, too. In fact, more particularly so. There continues to be a lot of debate about the safety of the solvents, particularly around propylene glycol and vegetable glycerin. Both have been designated by the US FDA as GRAS, or substances that are generally recognized as safe.

But Dr Gonzalez points out that these are GRAS for ingestion, not for inhalation. The cells that line the airway, after all, are different from the cells that line the stomach. It follows, too, that they respond to chemicals in different ways.

Several studies have shown, for example, that the aerosols from e-cigarettes mess with our respiratory tract even on a very basic, cellular level. Lab studies have shown that in response to these aerosols the cells that line the airway show signs of stress. Ultimately, such an exposure led to lower cell viability and an excess in the rate of cell death.

E-cigarette aerosols also assault the lungs. When exposed, in culture, to the aerosols, cells that line the tiny air sacs likewise show signs of stress and release indicators of cellular destruction. Aerosols might also make the lungs more susceptible to infection.

A 2016 study found that e-cigarette aerosols weaken the immune cells of the lungs. Mice who had inhaled these vapors showed altered inflammatory activity in their airways. To make things worse, the same type of exposure empowered Staphylococcus aureus, a common respiratory pathogen in humans. The bacteria grew more resistant to immune defenses, and became more potent—sticking to the host’s cells better and entering them with greater ease.

The outbreak of EVALI late last year in the US demonstrates that what happens in the lab isn’t just a test-tube artefact. Short for e-cigarette or vaping product use-associated lung injury, EVALI describes lung injuries and infections that were inexplicable except when seen in connection to the use of these devices.

Patients would present with unspecific symptoms: coughs, shortness of breath, and fevers. But in the most unfortunate cases, the disease would escalate and kill an otherwise healthy person.

Majority of cases were linked to vitamin E acetate, a common additive in juices that contained tetrahydrocannabinol, but a sizeable minority had no such connection. According to Dr Gonzalez, the culprit chemical (or chemicals) is still at large.

Though still such a very young phenomenon, there is already a substantial body of literature suggesting harms associated with vaping. It is true, however, that there’s a shortage of conclusive, unassailable, clinical evidence that vaping does more harm than good. All there is, still, is smoke, not a smoking gun.

The same can be said, though, of safety. There likewise hasn’t been irrefutable proof that these chemicals, and vaping in general, are completely devoid of serious health risks.

This is especially true in the face of all the flavorings. Many sweet flavors, like butter, caramel, and strawberry, owe their appeal to diacetyl, acetylpropionyl, and acetoin. Diacetyl is also GRAS for the stomach, but definitely not for the lungs. Used traditionally as the main butter flavoring in popcorn, diacetyl has since become notorious as the culprit behind bronchiolitis obliterans―more commonly known as popcorn lung.

Flavorings are also chiefly responsible for the aldehydes produced during vaping. Under heat, flavoring compounds break down into their aldehyde building blocks―like formaldehyde, benzaldehyde, and acrolein―in levels that exceed occupational safety thresholds.

“[Vapes] still do contain unidentified harmful chemicals and still-unidentified carcinogens because of the process of heating[…] They say it’s for harm-reduction, but in the long run, it’s still really not safe.”

Meritorious or disastrous? Only time will tell

There’s little doubt in her head that vapes will emerge more harmful than beneficial. But as of the moment, Dr Gonzalez concedes, there’s no way for us know, with a comfortable degree of statistical certainty, how harmful it truly is. It’s just still too early.

“Maybe in a few years,” she says, “though even now, we’re starting to see some cases of COPD. Before, it [used to take] about 20 to 30 years.” Vaping, in comparison, has been around 17 years, and only in the most recent handful years did it hit its stride. It’s going to take time for all the chronic side effects to arise, and even more time to study and peer-review any future findings.

Unfortunately, this high bar of scientific rigor is more of a convenience than a requirement for marketing. In the face of these sparsely substantiated claims, all health advocates like Dr Gonzalez can do is call for caution and wait.

“[Vapes] still do contain unidentified harmful chemicals and still-unidentified carcinogens because of the process of heating,” she says. “They say it’s for harm-reduction, but in the long run, it’s still really not safe.”—MF

*Not her real name.
This story was produced under the ‘Nagbabagang Kuwento Media Fellowship Program Cycle 4’ by Probe Media Foundation Inc. (PMFI) and Campaign for Tobacco Free Kids (CFTFK). The views and opinions expressed in this piece are not necessarily those of PMFI and CFTFK.

Author: Tristan Mañalac

Tristan is a journalist based in Metro Manila, focusing mainly on health, science, and the environment. He writes daily clinical news for MIMS.com and does in-depth reporting on the side. Being formally trained in the life sciences, he once dreamed of starting his own lab. But these days, he finds his greatest joy in a bottle of beer and a beautiful sentence.

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