The science of vapour: what actually happens when you inhale

To many, vaping looks like smoking. Clouds of vapour swirl in the air, often leading outsiders to assume the two are the same. But the science tells a different story. Vapour is not smoke, it is aerosol. That distinction matters because it defines the chemistry, the health impact and the experience. Understanding the science of vapour helps vapers make informed choices and pushes back against myths that refuse to die. So what actually happens when you inhale vapour, and why does it matter?

From liquid to vapour: the process

At the core of vaping is a simple transformation. An e liquid, usually made of propylene glycol (PG), vegetable glycerine (VG), flavourings and nicotine, is heated by a coil. The coil resists electricity, creating heat that turns the liquid into tiny aerosol droplets suspended in air. This is not burning, it is vaporisation. Unlike smoke, which contains carbon monoxide and tar from combustion, vapour is produced without fire. This absence of combustion is what makes vaping fundamentally different from smoking.

The chemistry of vapour

Vapour consists mostly of PG, VG, flavour molecules and, if included, nicotine. PG is thin, carrying flavour sharply and providing throat hit. VG is thicker, producing dense clouds and a smoother sensation. Together they create the base that holds flavour compounds, whether fruity, dessert like or menthol. Nicotine, if present, is carried in the aerosol droplets and absorbed in the lungs. Importantly, the by products of vaping are dramatically fewer than those of smoking. While trace compounds can form at high temperatures, the absence of combustion means the profile of vapour is far cleaner than that of smoke.

How vapour interacts with your lungs

When you inhale vapour, it travels through the airways into the lungs, where the aerosol droplets contact the alveoli, the tiny sacs responsible for gas exchange. Nicotine is absorbed here, moving rapidly into the bloodstream and reaching the brain within seconds. This quick delivery mimics the satisfaction of smoking but without the smoke. PG and VG are largely exhaled, though some is absorbed. Flavour compounds add sensory satisfaction, reinforcing the habit. The efficiency of absorption depends on device power, coil resistance and even the type of nicotine used, such as nicotine salts for a smoother, faster hit.

Vapour versus smoke: the crucial difference

Smoke is the product of burning plant material, releasing thousands of chemicals including carcinogens and toxins. Vapour is aerosol, containing far fewer chemicals, mostly food grade ingredients. Public Health England has repeatedly stated that vaping is significantly less harmful than smoking because of this difference. The science of vapour shows that while not entirely risk free, the absence of tar and carbon monoxide changes the risk profile completely. Conflating the two ignores the most basic chemical distinction, fire versus no fire.

Why vapour looks so thick

Many assume the density of vapour makes it more harmful. In reality, VG creates large, visible clouds because of its thick nature. These clouds may look dramatic, but they are mostly droplets of glycerine and water that quickly evaporate. Visibility is not an indicator of danger. Cigarette smoke, by contrast, may look lighter but is chemically more harmful. This is why cloud chasing with shortfills is a hobby for some vapers, producing spectacular vapour without the toxins of smoke.

Nicotine absorption and delivery

The science of vapour also explains nicotine satisfaction. Freebase nicotine, common in traditional e liquids, is harsher at higher strengths, making it better suited to sub ohm devices with lower concentrations. Nicotine salts allow higher strengths without harshness, making them ideal for pod kits and beginners who want a cigarette like hit. The flexibility of nicotine types is one reason vaping supports harm reduction so effectively, letting users tailor strength and delivery to their needs.

Temperature and chemistry

Temperature plays a big role in what happens to vapour. At optimal ranges, coils heat liquid efficiently into aerosol. At excessively high temperatures, unwanted compounds like formaldehyde can form, though usually in conditions outside normal use. Proper device settings, regulated coils and responsible maintenance prevent this. The UK’s regulatory framework ensures safety limits, banning unsafe additives and enforcing quality standards. Using tested products from trusted shops like Vape Lounge UK reduces risk by keeping devices and liquids within safe design parameters.

Exhaled vapour and the environment

What about passive exposure? Studies show that exhaled vapour dissipates quickly and leaves minimal residue compared with smoke. While trace nicotine can be detected in enclosed spaces, levels are low and far less harmful than second hand smoke. Vapour does not cling to furniture, stain walls or linger in the same way smoke does. This difference is central to why vaping is seen as less disruptive to environments, even though courtesy and respect for non vapers remain essential.

Common myths about vapour

• Myth: Vapour is just as dangerous as smoke. Fact: The absence of combustion makes vapour far less harmful.
• Myth: Big clouds mean more toxins. Fact: Cloud size reflects VG content, not chemical danger.
• Myth: Vapour coats your lungs in oil. Fact: PG and VG are water soluble and mostly exhaled.
• Myth: Nicotine itself causes cancer. Fact: Nicotine is addictive but not the carcinogenic element of smoking.

The psychology of inhaling vapour

Beyond chemistry, the science of vapour intersects with psychology. The act of inhaling, exhaling and seeing visible clouds reinforces ritual, mimicking the behavioural aspects of smoking. This is why vaping works as a replacement, addressing not only the chemical addiction to nicotine but also the habitual cues. Flavour, throat hit and cloud size all play roles in creating satisfaction that helps smokers stay away from cigarettes.

Why understanding the science matters

Ignorance fuels myths, and myths fuel bad policy. The 2019 US scare around vitamin E acetate showed how easily misinformation spreads. By understanding the science of vapour, vapers can counter false claims, advocate for harm reduction and educate others. For smokers on the fence, knowledge of what actually happens when you inhale vapour can mean the difference between switching and staying with cigarettes. Education is harm reduction in itself.

Final thoughts

The science of vapour shows a simple truth. Vapour is not smoke. It is aerosol, created without combustion, carrying nicotine and flavour with far fewer harmful by products. It interacts with the lungs quickly, delivering satisfaction while avoiding tar and carbon monoxide. It looks dramatic but is chemically clean compared with smoke. Myths may persist, but evidence is clear, vaping changes the chemistry of inhalation, and that change supports harm reduction. For vapers, understanding this science is power, a tool to cut through fear and misinformation.

Join the conversation and explore more

What do you think about the science of vapour? Have you had to explain the difference between vapour and smoke to someone? Share this post, start a discussion and help spread the facts.

Want to explore regulated products designed for satisfaction without combustion? Visit Vape Lounge UK and browse our e liquids, nicotine salts, shortfills, devices and accessories. Everything you need for a safe, satisfying vaping experience is right here.

If you would rather talk in person, come visit us at 147 Great Ancoats Street, Manchester M4 6DH or 71 Stafford Street, Stoke on Trent, ST1 1LW. You can also email hello@vapelounge.uk or call 0161 637 6066. We are here to help you explore vaping with confidence and clarity.