I. Executive Summary

Electronic cigarettes (e-cigarettes), commonly known as vapes, are often marketed or perceived as a safer alternative to traditional combustible cigarettes. However, a growing body of scientific evidence demonstrates that they are not harmless and pose significant, multifaceted health risks. This report synthesizes current knowledge from major health organizations, clinical research, and public health surveillance regarding these dangers. Central to the risks is nicotine, a highly addictive substance present in most e-cigarettes, which poses particular dangers to the developing adolescent brain.¹ Vaping exposes users to a complex aerosol containing numerous harmful and potentially harmful substances, including known carcinogens, heavy metals, volatile organic compounds (VOCs), and respiratory irritants like flavorings and ultrafine particles.³ Documented adverse health effects span multiple organ systems, including significant impacts on respiratory health (inflammation, lung injury, exacerbation of asthma, potential chronic disease) ⁶, cardiovascular function (increased heart rate and blood pressure, endothelial dysfunction, potential increased risk of heart attack and stroke) ⁹, and neurological development and function, especially in youth.¹ The rapid rise in youth vaping constitutes a major public health crisis, driven by appealing flavors and aggressive marketing tactics.¹² While vaping likely exposes users to fewer toxicants than smoking combustible cigarettes, the absolute risks associated with vaping itself are substantial, and long-term health consequences remain largely unknown due to their relatively recent emergence.⁸ The debate surrounding their potential role in harm reduction for adult smokers is complex and ongoing, particularly given the high rates of dual use (smoking and vaping concurrently) and the profound risks associated with youth initiation.

II. Introduction

Electronic cigarettes, or vapes, are battery-operated devices designed to heat a liquid solution (commonly termed “e-liquid” or “e-juice”) into an aerosol, which is then inhaled by the user.³ These devices have emerged relatively recently, proliferating globally over the past two decades, and have undergone rapid evolution in design, power output, and the chemical formulations of the e-liquids they utilize.⁶ Initially marketed by some as smoking cessation aids or less harmful alternatives to traditional cigarettes, their widespread adoption, particularly among adolescents and young adults who have never smoked, has raised significant public health concerns.¹²

This report aims to provide a comprehensive, evidence-based assessment of the known and potential health dangers associated with vaping. It draws upon scientific literature, including clinical studies, systematic reviews, and meta-analyses, as well as guidance and data from leading public health organizations such as the U.S. Centers for Disease Control and Prevention (CDC), the World Health Organization (WHO), and the UK’s National Health Service (NHS). Furthermore, it incorporates insights from recent news reports reflecting current public health discourse and regulatory perspectives. Understanding the full spectrum of risks associated with vaping is critical for informing individual choices, clinical guidance, public health policy, and regulatory actions designed to mitigate harm, especially among vulnerable populations.

III. The Science of Vaping Addiction

A. Nicotine: The Primary Addictive Agent

The vast majority of e-cigarettes sold contain nicotine, the same psychoactive and highly addictive chemical compound found in traditional tobacco products like cigarettes, cigars, and smokeless tobacco.¹ Nicotine exerts its addictive effects primarily by binding to nicotinic acetylcholine receptors in the brain, triggering the release of dopamine and other neurotransmitters that produce feelings of pleasure and reward. With repeated exposure, the brain adapts to the presence of nicotine, leading to tolerance (requiring more nicotine to achieve the same effect) and dependence, characterized by withdrawal symptoms upon cessation.¹

Nicotine addiction can develop with surprising speed, particularly in younger individuals whose brains are still developing. Signs of dependence can emerge quickly, sometimes even before a user transitions to regular or daily vaping.¹ Compounding the issue is the potential for inaccurate product labeling. Studies have detected nicotine in e-liquids marketed as containing zero nicotine, meaning users may be unknowingly exposed to and developing dependence on the substance.⁴

B. Nicotine Salts and Enhanced Addictiveness

A significant development in e-cigarette technology contributing to their addictive potential is the use of nicotine salts. Traditional “free-base” nicotine, found in older e-cigarette formulations and conventional cigarettes, is alkaline. When inhaled at high concentrations, it produces a harsh sensation in the throat, which can be a deterrent, especially for new users.² Nicotine salts are formed by adding an acid (like benzoic acid) to free-base nicotine, lowering its pH.² This chemical modification results in an aerosol that feels smoother and less irritating to inhale, even at very high nicotine concentrations.²

This technological shift has profound implications for addiction. The reduced harshness allows users, including adolescents experimenting with vaping, to inhale larger amounts of nicotine per puff without immediate discomfort.² Products like JUUL and many popular disposable vapes utilize nicotine salt formulations, delivering nicotine levels comparable to or even exceeding those of traditional cigarettes.⁴ The ability to easily inhale high doses leads to rapid absorption of nicotine into the bloodstream and swift delivery to the brain, mimicking the pharmacokinetic profile of cigarette smoking and strongly reinforcing the drug’s addictive potential.² This suggests that the development and popularization of nicotine salts may be a key factor fueling the rapid rise in youth vaping and nicotine dependence, effectively lowering the barrier to initiating and sustaining use of high-nicotine products.

C. Nicotine Withdrawal Syndrome

Once dependence is established, attempts to cease vaping typically lead to nicotine withdrawal syndrome. This manifests as a cluster of unpleasant physical and psychological symptoms as the body and brain readjust to the absence of nicotine.¹ Common symptoms include irritability, jumpiness, restlessness, anxiety, depressed mood or sadness, difficulty sleeping (insomnia), problems concentrating, increased appetite or hunger, and powerful cravings for nicotine.¹ Headaches can also occur.¹⁹

These withdrawal symptoms can be highly distressing and significantly impair daily functioning, affecting mood, relationships, and performance in school or work.¹ The desire to alleviate these symptoms often drives individuals back to vaping, creating a challenging cycle of dependence.¹⁸ Furthermore, nicotine addiction itself can be a source of stress, and the withdrawal process can exacerbate feelings of anxiety and depression, potentially intertwining with pre-existing mental health concerns, particularly among adolescents.¹

IV. Hazardous Components of E-cigarette Aerosol

A critical misconception is that the emissions from e-cigarettes consist merely of harmless “water vapor.” In reality, the aerosol produced by heating the e-liquid is a complex mixture containing numerous potentially harmful substances.² The base e-liquid typically comprises nicotine, solvents such as propylene glycol (PG) and vegetable glycerin (VG), chemical flavorings, and various other additives.³ The intense heat generated by the device’s coil (reaching temperatures of 100–250 °C or higher) not only aerosolizes these ingredients but also causes chemical reactions, including pyrolysis and oxidation, leading to the formation of new, often toxic, compounds not present in the original liquid.⁵ Research has identified thousands of chemicals in vape aerosol, many of which remain unidentified.²²

A. Key Toxicants Identified

While the exact composition varies, numerous hazardous substances have been consistently identified in e-cigarette aerosol:

• Nicotine: As previously discussed, this highly addictive substance is present in most products and poses significant health risks, particularly to adolescent brain development and cardiovascular health.¹
• Volatile Organic Compounds (VOCs): These include chemicals like benzene, which is also found in car exhaust and is a known human carcinogen, and formaldehyde, another carcinogen.¹ Exposure to VOCs can irritate the eyes, nose, and throat, cause headaches and nausea, and potentially damage the liver, kidneys, and nervous system.²¹ Formaldehyde, in particular, can be formed when the e-liquid overheats or if insufficient liquid reaches the heating element (a “dry puff”).⁷
• Carbonyl Compounds: This group includes acetaldehyde and acrolein, both potent respiratory irritants.³ Acrolein, also used as a herbicide, is particularly concerning as it can cause acute lung injury, contribute to the development of Chronic Obstructive Pulmonary Disease (COPD), and may play a role in asthma and lung cancer.⁵ These aldehydes are often generated by the thermal degradation of the solvents PG and VG.⁶
• Heavy Metals: Toxic metals such as lead, nickel, tin, cadmium, and chromium have been detected in e-cigarette aerosol.¹ These metals are believed to leach from the device components, particularly the heating coil and other metal parts that come into contact with the e-liquid.²² Inhalation of these metals is associated with various health problems, including respiratory irritation, lung disease, cardiovascular issues, kidney damage, and potential carcinogenicity.³¹ Alarmingly, studies have found concentrations of some metals in vape aerosol to be higher than or equal to those found in conventional cigarette smoke.²⁴
• Flavoring Chemicals: E-liquids come in thousands of flavors, often designed to appeal to youth.⁴ While many flavoring chemicals are considered safe for ingestion (eating), their safety when inhaled into the lungs is often unknown and potentially hazardous.¹ The lungs process substances differently than the digestive system.¹ Diacetyl, a buttery-flavor chemical, has been linked to a severe, irreversible lung disease called bronchiolitis obliterans, also known as “popcorn lung”.³ Other flavoring chemicals like cinnamaldehyde have also raised toxicological concerns.²³
• Ultrafine Particles: The aerosol itself consists of a high concentration of ultrafine particles (nanoparticles).¹ Due to their small size, these particles can penetrate deep into the lung tissues and potentially enter the bloodstream.¹ Inhalation of ultrafine particles is associated with respiratory inflammation, exacerbation of asthma, and cardiovascular problems.²⁴ Particle concentration in e-cigarette aerosol can be even higher than in traditional cigarette smoke.²⁴
• Other Harmful Substances:

• Solvents (PG and VG): While generally recognized as safe for ingestion, inhaling PG and VG can be toxic to lung cells and cause airway irritation.⁶ Their heating is a primary source of harmful carbonyl compounds.²²
• Tobacco-Specific Nitrosamines (TSNAs): These potent carcinogens, derived from tobacco, have been detected in some e-liquids and aerosols, likely as impurities from nicotine extraction.²²
• Diethylene Glycol: A toxic chemical found in antifreeze, linked to lung disease, has been detected in some e-cigarette products.³
• Contaminants: E-liquids have sometimes been found to be contaminated with microbes like fungi and bacteria.²²

B. Factors Influencing Aerosol Composition

It is crucial to understand that the chemical profile of the aerosol inhaled by a vaper is not fixed but highly variable. The specific types and amounts of harmful chemicals generated depend on a complex interplay of factors ¹²:

• E-Liquid Composition: The specific ingredients, including the type and concentration of nicotine, the ratio of PG to VG, and the particular flavoring chemicals used, significantly influence the aerosol’s makeup.⁶ Different flavors can produce different toxic byproducts when heated.⁷
• Device Characteristics: The device’s power output (voltage/wattage), the resistance and material of the heating coil, and the device’s age and maintenance can all affect the temperature reached during heating and, consequently, the chemical reactions that occur.²² Higher temperatures generally lead to increased formation of harmful aldehydes like formaldehyde.²¹
• User Behavior: How the individual uses the device—including the duration and intensity of puffs (puff topography)—impacts the heating dynamics and aerosol generation.²² Longer, harder puffs can potentially lead to higher temperatures and greater toxicant production.

This inherent variability creates an unpredictable risk profile for users. The lack of standardization across products, combined with the potential for users to modify devices or liquids ¹³, means that individual exposure levels can differ dramatically. This dynamic nature challenges simplistic comparisons to cigarette smoke and makes it difficult to establish a definitive “safe” level of vaping, as specific combinations of liquid, device, and usage patterns could potentially generate high concentrations of certain harmful substances.²²

C. Table: Harmful Chemicals in E-cigarette Aerosol

To consolidate this information, the following table summarizes key hazardous chemical classes found in e-cigarette aerosol, providing examples, likely sources, and major associated health concerns based on the evidence reviewed.

Chemical Class	Examples	Potential Sources	Major Associated Health Risks	Supporting Sources
Nicotine	Nicotine (Free-base, Salts)	E-liquid (primary ingredient)	Addiction, cardiovascular effects (↑HR, ↑BP), harmful to adolescent brain development, toxic to fetuses	1
Volatile Organic Compounds (VOCs)	Formaldehyde, Acetaldehyde, Benzene, Toluene	Heating of solvents (PG/VG), flavorings; E-liquid	Carcinogenicity (formaldehyde, benzene), respiratory irritation, neurological effects, organ damage (liver, kidney)	1
Carbonyl Compounds	Acrolein, Acetaldehyde	Heating of solvents (PG/VG), flavorings	Acute lung injury (acrolein), COPD, asthma, cardiovascular disease, respiratory irritation	3
Heavy Metals	Lead, Nickel, Tin, Chromium, Cadmium	Leaching from heating coil, device components	Respiratory problems, lung disease, cardiovascular effects, kidney damage, potential carcinogenicity	1
Flavoring Chemicals	Diacetyl, Cinnamaldehyde, Vanillin, Benzaldehyde	E-liquid (additives)	Bronchiolitis obliterans (“Popcorn Lung” – Diacetyl), respiratory irritation, cellular toxicity, cardiovascular effects (some flavors), unknown long-term effects	3
Ultrafine Particles	Nanoparticles (<100 nm)	Aerosolization process	Deep lung penetration, respiratory inflammation, exacerbation of asthma, cardiovascular effects	1
Other Toxicants	Propylene Glycol (PG), Vegetable Glycerin (VG), TSNAs, Diethylene Glycol	E-liquid (solvents, impurities), heating degradation	Airway irritation (PG/VG), cellular toxicity (PG/VG), carcinogenicity (TSNAs), lung disease (Diethylene Glycol)	5

(Note: This table is illustrative and not exhaustive. HR=Heart Rate, BP=Blood Pressure, COPD=Chronic Obstructive Pulmonary Disease, TSNAs=Tobacco-Specific Nitrosamines)

V. Systemic Health Impacts of Vaping

Exposure to the complex chemical mixture in e-cigarette aerosol can adversely affect multiple organ systems throughout the body. While research is ongoing, particularly regarding long-term effects, significant evidence points to detrimental impacts on respiratory, cardiovascular, neurological, and other systems.

A. Respiratory Consequences

The lungs are the primary site of exposure to vape aerosol, and evidence indicates a range of adverse respiratory effects:

• Short-Term Irritation: Common immediate effects include coughing, shortness of breath, wheezing, irritation of the throat and eyes, headaches, and sometimes nausea.³
• Inflammation and Cellular Damage: Inhaled particles and chemicals directly irritate and inflame lung tissues.³ Studies have demonstrated that the primary e-liquid solvents, PG and VG, are toxic to lung cells in laboratory settings.⁶ Chronic inflammation can lead to structural damage, including potential scarring (fibrosis) and narrowing of the airways.³
• Exacerbation of Existing Conditions: There is moderate evidence linking vaping to increased frequency or severity of symptoms in individuals with pre-existing respiratory conditions. This includes increased coughing, wheezing, and exacerbations in individuals with asthma, particularly youth.⁶ Vaping may also worsen symptoms of COPD.⁶
• Specific Lung Diseases: Certain severe lung conditions have been associated with vaping. Bronchiolitis obliterans (“popcorn lung”), characterized by irreversible scarring of the small airways, has been linked to exposure to the flavoring chemical diacetyl.³ Other reported conditions include various forms of pneumonia (such as lipoid pneumonia, potentially linked to inhaled oils in e-liquids, and eosinophilic pneumonia), interstitial lung diseases, and diffuse alveolar hemorrhage.⁷ Cases of collapsed lung (pneumothorax) have also been reported in vapers.²⁷
• EVALI (E-cigarette or Vaping Use-Associated Lung Injury): The 2019 outbreak highlighted the potential for severe, acute lung injury related to vaping. EVALI presented with symptoms including cough, shortness of breath, chest pain, fever, gastrointestinal issues (vomiting, diarrhea), and sometimes rapid respiratory failure requiring hospitalization.³ While the outbreak was strongly linked to vitamin E acetate, an additive used primarily in illicit THC-containing vape cartridges ³, it underscored the potential for inhaled substances in vape products to cause severe lung damage.⁷ The outbreak resulted in thousands of hospitalizations and dozens of deaths across the U.S..³
• Increased Risk of Chronic Lung Disease: Longitudinal studies tracking individuals over time have begun to emerge. A significant finding from the large U.S. Population Assessment of Tobacco and Health (PATH) study indicated that e-cigarette users had a significantly increased risk of developing chronic lung diseases, including asthma, bronchitis, emphysema, or COPD, compared to non-users, independent of their smoking history.²⁵ Importantly, individuals who engaged in dual use (vaping and smoking cigarettes concurrently) faced the highest risk, substantially greater than those using only one product.³⁹ While some analyses focusing specifically on never-smokers found limited evidence of this association due to small sample sizes in early cohorts ⁴⁶, the overall trend points towards vaping contributing to chronic respiratory conditions over time.

B. Cardiovascular Consequences

The cardiovascular system is also significantly affected by vaping, with effects observed both acutely and potentially chronically:

• Acute Hemodynamic Effects: Vaping typically causes an immediate increase in both heart rate and blood pressure.⁷ Meta-analyses confirm these acute effects compared to non-use.¹⁰ Comparisons with acute effects of smoking are complex; some studies suggest the heart rate increase might be slightly lower with vaping, while blood pressure effects appear similar or findings are inconsistent.⁴⁸
• Vascular Dysfunction: Accumulating evidence points to detrimental effects on blood vessel health. Studies report endothelial dysfunction, which is an impairment in the normal function of the cells lining the blood vessels, a key early step in the development of atherosclerosis (hardening of the arteries).⁷ Increased arterial stiffness (making arteries less flexible) and vasoconstriction (narrowing of blood vessels) have also been observed.⁷ Underlying mechanisms likely involve increased oxidative stress, inflammation within the blood vessels, and reduced production or availability of nitric oxide, a crucial molecule for maintaining vascular health.⁷ Some research suggests these effects may not solely be due to nicotine; flavorings ³⁶ and the physical act of inhaling irritants ¹¹ may also play roles. This indicates a complex pathophysiology where multiple components of the aerosol contribute to vascular harm, challenging the notion that vaping is benign for the cardiovascular system simply because it avoids combustion products like tar.
• Adverse Cardiovascular Risk Markers: Research has shown that the blood of chronic e-cigarette users contains elevated levels of certain biomarkers associated with increased cardiovascular risk. Interestingly, some of these markers differ from those typically elevated in traditional smokers, suggesting potentially distinct pathways of harm.¹¹ For example, studies found that blood from vapers caused increased permeability in cultured blood vessel cells compared to blood from smokers or non-users.¹¹
• Association with Cardiovascular Events: Epidemiological studies have linked e-cigarette use with increased odds of experiencing serious cardiovascular events. Several analyses report a significantly higher risk of myocardial infarction (heart attack) among e-cigarette users compared to non-users.¹⁰ Some studies also suggest an increased risk of stroke.¹² The risk appears particularly elevated for dual users; one large study found daily dual users had nearly five times the odds of a heart attack compared to non-users.³³ However, it is important to note that some systematic reviews conclude there is currently limited evidence directly linking vaping to established clinical cardiovascular disease outcomes (like diagnosed coronary heart disease or long-term cardiac remodeling), emphasizing the need for longer-term follow-up studies.¹²

C. Neurological and Mental Health Consequences

Nicotine’s effects on the brain are profound, especially during critical developmental periods:

• Impact on Adolescent Brain Development: The human brain continues to develop until about age 25.¹ Nicotine exposure during adolescence and young adulthood can disrupt the maturation of brain circuits, particularly those involved in attention, learning, memory, mood regulation, and impulse control.¹ This can lead to long-lasting deficits in cognitive function and emotional regulation.
• Cognitive Effects: Vaping, through nicotine exposure, may impair memory, concentration, and executive functions, potentially impacting academic performance and daily tasks.¹³
• Increased Risk of Other Addictions: Nicotine exposure during adolescence can alter brain chemistry in ways that increase vulnerability to addiction to other drugs later in life. This “gateway” effect suggests that early nicotine dependence from vaping could have broader implications for substance use behaviors.¹
• Seizures: There have been reports submitted to regulatory agencies, such as the U.S. FDA, concerning seizures occurring in individuals after vaping, with reports most common among youth and young adults.¹ While the exact cause is under investigation, high nicotine concentrations (“nicotine toxicity”) are suspected to play a role.⁷
• Mental Health Associations: Studies consistently show an association between vaping among youth and young adults and mental health challenges, including increased symptoms of depression, anxiety, and stress.¹ Some research also suggests links with ADHD symptoms.⁴⁰ While the directionality of this relationship is complex (i.e., does vaping contribute to mental health issues, or do individuals with these issues self-medicate with nicotine?), there is concern that nicotine dependence itself acts as a stressor and that youth may initiate or continue vaping in an attempt to cope with anxiety or stress, thereby perpetuating a cycle of dependence and potentially worsening underlying issues.¹⁸

D. Carcinogenic Potential

While cigarette smoking is unequivocally linked to numerous cancers due to the thousands of chemicals produced during combustion, the carcinogenic potential of vaping is still under investigation, primarily due to its shorter history of widespread use.

• Presence of Carcinogens: As established, e-cigarette aerosol is not free of carcinogens. It contains known cancer-causing agents such as formaldehyde, acetaldehyde, benzene, and tobacco-specific nitrosamines (TSNAs), although generally at lower levels than in cigarette smoke.¹ Heavy metals like cadmium and nickel found in the aerosol also have carcinogenic potential.²⁴
• Biomarker Evidence of Cancer Risk: While long-term cancer outcome data is lacking, numerous studies using biomarkers provide concerning evidence. Research shows that exposure to e-cigarette aerosol is associated with biological changes relevant to cancer development. These include increased oxidative stress (an imbalance harmful to cells), DNA damage (mutations) and strand breaks, impaired DNA repair mechanisms, increased cellular apoptosis (programmed cell death) and necrosis (uncontrolled cell death), genotoxicity (damage to genetic material), and potentially promotion of tumor growth characteristics in cell models.⁷ Specific studies have documented DNA damage in cells lining the mouth and airways following vape exposure.⁷ These molecular and cellular changes represent crucial steps in the process of carcinogenesis. Although they do not constitute definitive proof that vaping causes cancer in humans, they provide strong biological plausibility for such a risk and serve as critical early warning signs. This evidence directly challenges assertions of vaping’s long-term safety and justifies a precautionary approach, particularly regarding preventing initiation among young people.
• Current Understanding of Cancer Risk: Based on current evidence, major health bodies conclude that while vaping likely poses a lower cancer risk than smoking combustible cigarettes, it is not risk-free.¹⁵ There is currently no conclusive epidemiological evidence establishing a causal link between vaping and cancer incidence in humans.¹⁵ This is largely because cancers typically have long latency periods (decades), and widespread vaping is a relatively recent phenomenon.¹⁵ Therefore, long-term population studies are essential to fully quantify the cancer risk associated with chronic vaping.⁷

E. Other Adverse Effects

Beyond the major organ systems, vaping is associated with several other health concerns and risks:

• Oral Health Problems: Users frequently report dry mouth and throat irritation.³ Vaping is also linked to gum inflammation (gingivitis) and an increased risk of periodontal (gum) disease.⁷ The viscous nature of e-liquids (due to PG/VG) and the presence of sugars in many flavorings can promote bacterial plaque adhesion and potentially increase the risk of dental caries (cavities).¹³ Damage to tooth enamel and the development of oral mucosal lesions (sores or abnormal patches in the mouth) have also been reported.⁷
• Immune System Modulation: Emerging research suggests that vaping can impact the immune system. Studies have shown alterations in both innate (first-line defense) and acquired (adaptive) immunity in vapers, including changes in the expression of immune-related genes in nasal passages and increased production of certain inflammatory markers.⁷ While the functional consequences are still being investigated, these changes could potentially affect the body’s ability to fight infections.²⁵
• Acute Nicotine Poisoning: E-liquids, especially those in high concentrations, pose a significant poisoning risk if ingested, inhaled directly (not aerosolized), or absorbed through the skin or eyes. This is a particular danger for young children who might accidentally access unsecured e-liquids.¹ Symptoms of nicotine poisoning can include nausea, vomiting, dizziness, rapid heart rate, breathing difficulties, and in severe cases, seizures and even death.⁴¹ A large proportion of calls to U.S. poison control centers regarding e-cigarettes involve accidental exposure in children under five years old.¹
• Device Safety Issues: Beyond the chemical risks, the devices themselves can pose physical hazards. Defective lithium-ion batteries used in many vaping devices have been known to overheat, catch fire, or explode, causing serious burns and other traumatic injuries.¹ These incidents often occur while the device is charging.¹ Additionally, the use of modified or “bootleg” devices and liquids obtained from unregulated sources carries risks of malfunction and exposure to unknown, potentially dangerous substances.¹³

F. Secondhand Aerosol Exposure and Risks

The aerosol exhaled by e-cigarette users, often referred to as secondhand aerosol (SHA), is not simply harmless “water vapor”.⁴ The U.S. Surgeon General has concluded that SHA is not harmless.⁶ It contains a mixture of potentially harmful substances that can expose bystanders, including children, to risks.²¹

• Composition of Secondhand Aerosol: SHA contains nicotine, ultrafine particles, volatile organic compounds (VOCs) like formaldehyde and benzene, heavy metals (such as lead, nickel, tin, chromium), and various flavoring chemicals.¹ Some of these components, including certain VOCs and metals, are known carcinogens.⁷ Propylene glycol, a common e-liquid ingredient also found in SHA, can cause eye, throat, and airway irritation, and long-term inhalation exposure may contribute to asthma development in children.²⁴
• Exposure Levels in Indoor Environments: Vaping indoors significantly increases the concentration of airborne particulate matter (PM2.5 and ultrafine particles) compared to background levels.²⁴ Studies have measured substantial increases in PM2.5 in various indoor settings:

• Rooms: Peak PM2.5 concentrations can reach very high levels immediately after puffing (e.g., ~3 × 10³ µg/m³ near the user), dropping quickly but still elevating overall room levels.⁷⁶ Average PM2.5 levels during vaping sessions in rooms have been measured at levels significantly above background (e.g., 21 µg/m³ ⁷⁸, 197 µg/m³ ⁷⁵). Vape shops can have particularly high average PM2.5 concentrations (e.g., 276 µg/m³).⁷⁴ These levels can exceed WHO 24-hour air quality guidelines (15 µg/m³).⁷⁰
• Cars: Vaping in cars also elevates PM2.5 levels, with measured concentrations ranging from 16 µg/m³ to over 100 µg/m³ during sessions.⁷⁸ The small volume of cars can lead to high concentrations.⁷⁹
• Nicotine: Nicotine is consistently detected in the air of indoor environments where vaping occurs, including homes and vape shops.⁷¹ Bystanders exposed to SHA absorb nicotine, as evidenced by biomarkers like cotinine in their bodies.²⁴ Nicotine also deposits on indoor surfaces, creating potential for thirdhand exposure.⁷
• Health Effects, Especially on Children: Exposure to SHA is associated with adverse health effects, particularly respiratory issues:

• Studies link SHA exposure to increased risk of bronchitic symptoms and shortness of breath in young adults.⁶⁹ Bystanders exposed have reported irritation symptoms like dry throat, nose, eyes, and cough.⁷¹
• For children, SHA exposure poses specific risks. It is associated with an increased likelihood of asthma attacks or exacerbations.⁶⁸ One study found youth with asthma exposed to SHA had 27% higher odds of reporting an asthma attack in the past year.⁸⁸ Another suggested exposure at home leads to more asthma symptoms, especially in younger children (ages 5-11).⁹³
• The nicotine in SHA is a concern for children’s developing brains.⁶⁶ While children exposed only to SHA absorb significantly less nicotine than those exposed to secondhand smoke (about 84% lower based on cotinine levels), they still absorb significantly more nicotine than unexposed children.⁸³
• Given these risks, health authorities recommend prohibiting vaping in indoor spaces to protect bystanders, especially children.²⁴

VI. Vaping Risks in Vulnerable Populations

While vaping poses risks to all users, certain populations are particularly vulnerable to its adverse effects due to biological susceptibility or developmental stage.

A. Adolescents and Young Adults

The rapid uptake of vaping among youth globally has been widely described as a public health epidemic.¹³ While recent surveys in the U.S. indicate a decline from peak levels in 2019, millions of middle and high school students still report current vaping.⁵⁴ Worryingly, a significant proportion of these young users vape frequently (e.g., 20 or more days per month, or daily), suggesting established nicotine dependence.¹² Several factors make this age group uniquely vulnerable:

• Neurological Vulnerability: As detailed previously, the adolescent brain is undergoing critical development, making it highly sensitive to the disruptive effects of nicotine. Exposure during this window can lead to lasting impairments in cognitive functions like attention, learning, and memory, as well as problems with impulse control and mood regulation.¹
• Heightened Addiction Susceptibility: Adolescents appear to be more sensitive to nicotine’s rewarding effects and can become dependent more quickly and potentially at lower levels of exposure compared to adults.¹ Product characteristics like appealing flavors and the smooth delivery of high nicotine concentrations via nicotine salts significantly facilitate initiation and the rapid development of addiction in this group.²
• Potential Gateway to Smoking: Multiple longitudinal studies have found that young people who initiate nicotine use with e-cigarettes are significantly more likely to subsequently start smoking traditional combustible cigarettes compared to their peers who do not vape.¹ While the exact mechanisms are debated, this association raises concerns that vaping, rather than solely diverting youth from smoking, may also serve as an entryway to tobacco use for individuals who might otherwise have remained nicotine-free.¹⁴
• Influence of Marketing and Flavors: The youth vaping epidemic has been strongly linked to the proliferation of kid-friendly flavors (such as fruit, candy, mint, and menthol) and targeted marketing strategies.⁴ Surveys consistently show that flavors are the primary reason young people try and continue to use e-cigarettes.¹⁴ Marketing often employs themes of youthfulness, rebellion, and social status, utilizing channels popular with adolescents, including social media platforms like TikTok and Instagram.³² Regulatory efforts to curb youth access and appeal have faced challenges. For instance, restrictions on flavored pod-based systems led to a rapid market shift towards flavored disposable e-cigarettes, which remained widely available and popular among teens.¹² This dynamic illustrates the “flavor trap”: the industry’s ability to adapt and continue supplying appealing flavored products that attract and hook young users, despite known risks to their health and development. Loopholes, such as the legality of giving free samples in some jurisdictions ⁵² and illicit markets often originating from overseas ⁵⁷, further complicate prevention efforts. Addressing the youth vaping crisis effectively likely requires comprehensive regulations that eliminate all characterizing flavors attractive to minors.

B. Pregnant Individuals and Fetal Development

Vaping during pregnancy poses significant risks to both the pregnant individual and the developing fetus. Health authorities strongly advise against the use of any nicotine-containing products, including e-cigarettes, during pregnancy.¹

• Nicotine Toxicity to the Fetus: Nicotine readily crosses the placenta and is toxic to the developing fetus. It can adversely affect fetal brain development, potentially leading to cognitive and behavioral problems later in life, and can also impair lung development.¹
• Adverse Birth Outcomes: Studies have linked maternal e-cigarette use during pregnancy with negative birth outcomes, including low birth weight and pre-term delivery.¹ One systematic review noted that while many side effects were similar to smoking, lower birth weight was specifically associated with ENDS exposure during pregnancy.³⁷
• Unknown Risks of Other Chemicals: Beyond nicotine, the potential effects of inhaling the various other chemicals present in e-cigarette aerosol (solvents, flavorings, metals, etc.) on fetal development are largely unknown but represent an additional layer of concern.²⁶ Given the established harms of nicotine and the uncertainties surrounding other aerosol constituents, avoiding vaping during pregnancy is the safest course of action.

VII. Comparative Risks: Vaping vs. Cigarette Smoking

A central point of debate and public confusion surrounds the relative harms of vaping compared to smoking traditional combustible cigarettes.

A. The Harm Reduction Argument

Proponents of vaping often emphasize its potential for harm reduction, particularly for adult smokers who are unable or unwilling to quit nicotine altogether. This argument rests on the fundamental difference between the two products: cigarettes burn tobacco, releasing thousands of chemicals in smoke, whereas e-cigarettes heat a liquid to produce an aerosol.¹⁵

• Reduced Toxicant Exposure: The absence of combustion in vaping means that many of the most harmful components of cigarette smoke, such as tar and carbon monoxide, are either absent or present at much lower levels in e-cigarette aerosol.⁵¹ Studies consistently show that levels of many key toxicants and carcinogens (including TSNAs and VOCs) are significantly lower in vape aerosol compared to cigarette smoke.¹
• Biomarker Evidence in Switchers: Research measuring biomarkers of exposure in the bodies of smokers who switch completely to vaping generally shows substantial reductions in levels of harmful substances associated with smoking-related diseases like cancer, lung disease, and cardiovascular disease.²³ This provides biological evidence supporting the claim that switching entirely from smoking to vaping results in reduced exposure to major tobacco toxicants. Organizations like Public Health England (now Office for Health Improvement and Disparities) and Cancer Research UK have concluded, based on such evidence, that vaping is likely substantially less harmful than smoking.¹⁵

B. Absolute Risks and Uncertainties

While vaping may be less harmful than smoking, it is crucial to recognize that it is not harmless. The harm reduction argument must be balanced against the absolute risks inherent in vaping itself:

• Inherent Dangers of Vaping: As detailed extensively in previous sections, vaping involves inhaling nicotine (a highly addictive drug with its own health risks) and a cocktail of other potentially harmful chemicals, including carcinogens, respiratory irritants, heavy metals, and ultrafine particles.¹ These exposures are linked to addiction, respiratory problems, cardiovascular effects, and potential long-term consequences.¹
• Lack of Long-Term Data: E-cigarettes are a relatively new product category. Consequently, robust long-term epidemiological data on the health effects of sustained vaping over decades (comparable to the data available for smoking) does not yet exist.¹ Many smoking-related diseases, such as cancer and COPD, develop over long periods, meaning the full picture of vaping’s chronic disease risk may not emerge for many years.

C. The Danger of Dual Use

A significant challenge to the harm reduction potential of e-cigarettes is the phenomenon of dual use. Many adults who take up vaping do not completely quit smoking but instead use both products concurrently.¹

• Increased Overall Risk: Evidence suggests that dual use may not reduce harm and could potentially be more dangerous than smoking alone. Studies have associated dual use with higher risks of cardiovascular disease and respiratory symptoms compared to exclusive smoking.¹ This implies that unless vaping leads to complete and sustained cessation of combustible cigarettes, any potential harm reduction benefits may be negated or even reversed.

D. Vaping for Smoking Cessation

The effectiveness and appropriateness of using e-cigarettes as a tool to quit smoking remain subjects of considerable debate and differing public health approaches.

• Evidence for Effectiveness: Several randomized controlled trials and systematic reviews suggest that nicotine-containing e-cigarettes can be effective aids for smoking cessation, potentially more effective than traditional nicotine replacement therapies (NRT) like patches or gum, particularly when combined with behavioral support.¹² Some smokers find the hand-to-mouth action and sensory experience of vaping helpful in replacing smoking behaviors.⁵⁹ Based on this evidence, health bodies in the UK, such as the NHS and Cancer Research UK, recommend vaping as a viable option for adult smokers trying to quit.¹⁵
• Counterarguments and Concerns: Conversely, major U.S. health organizations like the FDA and the American Lung Association have not approved any e-cigarette product as a safe and effective smoking cessation therapy.⁶ Concerns persist that vaping might discourage or delay complete nicotine cessation for some individuals.²⁹ Furthermore, some research indicates that smokers who quit using e-cigarettes may face higher cardiovascular risks compared to those who quit without using alternative nicotine products.³⁹
• Contextual Differences in Public Health Stance: The differing stances on vaping for cessation between regions like the UK and the US likely reflect varying public health priorities and contexts. The UK, with a strong historical focus on reducing the immense harm from combustible tobacco, may view vaping more favorably as a significantly less harmful alternative for entrenched adult smokers.³⁴ The US, grappling with alarmingly high rates of youth vaping initiation and addiction, places a greater emphasis on preventing youth uptake and the absolute risks of vaping itself, leading to a more cautious approach towards promoting e-cigarettes, even for cessation.¹ These differing perspectives highlight how the interpretation and application of scientific evidence can be shaped by specific national public health challenges and regulatory environments, rather than solely by the scientific findings themselves.

VIII. Conclusion

The scientific evidence accumulated to date clearly indicates that electronic cigarette use, or vaping, is not a benign activity and carries significant health risks. While often positioned as less harmful than traditional smoking, vaping exposes users to the highly addictive drug nicotine and a complex aerosol containing numerous toxic substances, including carcinogens, heavy metals, volatile organic compounds, and ultrafine particles.

Key dangers identified include the profound risk of nicotine addiction, which can develop rapidly and has particularly detrimental effects on the developing brains of adolescents and young adults. Vaping is associated with adverse respiratory effects ranging from acute irritation and inflammation to exacerbation of existing conditions like asthma and an increased risk of developing chronic lung diseases. Cardiovascular harms include acute increases in heart rate and blood pressure, endothelial dysfunction, arterial stiffness, and an elevated risk of heart attack and stroke, especially among dual users. Concerning biomarkers suggest a potential for long-term cancer risk, although definitive epidemiological evidence requires more time. Other documented risks include oral health problems, potential immune system impacts, acute nicotine poisoning, injuries from device malfunctions, and exposure to harmful secondhand aerosol.

Vulnerable populations, particularly youth and pregnant individuals, face heightened risks. The epidemic of youth vaping, fueled by appealing flavors and targeted marketing, poses a severe threat to a generation’s health, potentially reversing decades of progress in tobacco control and creating pathways to nicotine dependence and other substance use.

While complete substitution of vaping for smoking may reduce exposure to some toxicants for adult smokers, this potential benefit must be weighed against the absolute risks of vaping itself and the significant danger posed by dual use. The long-term health consequences of sustained vaping remain largely unknown.

Therefore, based on the current evidence, strong public health measures are warranted. These include robust regulations to prevent youth access and initiation (such as comprehensive flavor bans and strict marketing controls), continued research into long-term health effects and effective cessation strategies for vapers, and clear, accurate public health communication to ensure individuals understand the real risks associated with e-cigarette use. Avoiding the initiation of vaping, especially among youth and non-smokers, remains a critical public health priority.

IX. References

This report synthesized information from numerous sources, including reports from major health organizations, peer-reviewed scientific studies (including clinical trials, systematic reviews, and meta-analyses), and recent news articles. A selection of key references informing this report is listed below.

Clinical Studies, Systematic Reviews, and Meta-Analyses (Selected Examples):

1. Bhatta, D. N., & Glantz, S. A. (2020). Electronic Cigarette Use and Myocardial Infarction Among Adults in the US Population Assessment of Tobacco and Health. Journal of the American Heart Association, 9(12), e014570. (Related evidence discussed in ³³)
2. Banks, E., Yazidjoglou, A., Brown, S., et al. (2024). Electronic cigarettes and health outcomes: umbrella and systematic review of the global evidence. Medical Journal of Australia, 220(5), 237-246. ⁴³
3. Gotts, J. E., Jordt, S. E., McConnell, R., & Tarran, R. (2019). What are the respiratory effects of e-cigarettes?. BMJ, 366, l5275. (Related evidence discussed across respiratory sections, e.g.⁸)
4. Jonas, A. (2022). Impact of vaping on respiratory health. BMJ, 378, e065997. ⁸
5. Kaur, G., Robertson, T. P., et al. (2020). Effects of Vaping on Respiratory, Cardiovascular, and Muscle Function: A Comparison Between Vaping and Smoking. Frontiers in Physiology, 11, 676. ²⁶
6. Lee, M. S., Allen, J. E., et al. (2019). E-cigarette Use and Respiratory Symptoms in Adolescents and Young Adults: A Systematic Review and Meta-analysis. JAMA Pediatrics, 173(11), 1060–1068. (Related evidence discussed in ³⁸)
7. Margham, J., et al. (2021). The Chemical Complexity of e-Cigarette Aerosols Compared With the Chemical Complexity of Cigarette Smoke. Nicotine & Tobacco Research, 23(10), 1675–1684. ²³
8. Qasim, H., Karim, Z. A., Rivera, J. O., Khasawneh, F. T., & Alshbool, F. Z. (2017). Impact of Electronic Cigarettes on the Cardiovascular System. Journal of the American Heart Association, 6(9), e006353. (Related evidence discussed across cardiovascular sections, e.g.⁹)
9. Rahman, M. A., et al. (2023). Characterization and Summarization of the Impact of Electronic Cigarettes on the Cardiovascular System: A Systematic Review and Meta-Analysis. Cureus, 15(6), e40943. ¹⁰
10. St. Helen, G., et al. (2022). NIH-funded studies show damaging effects of vaping, smoking on blood vessels. National Institutes of Health News Release. ¹¹ (Describes findings from studies published in Arteriosclerosis, Thrombosis, and Vascular Biology (ATVB))
11. Wills, T. A., et al. (2021). E-cigarette use and respiratory disorders: examining the relationship in adolescents and young adults. American Journal of Preventive Medicine, 60(4), 513-521. (Related evidence discussed in ³⁹)
12. Xie, W., et al. (2025). Cardiovascular health effects of vaping e-cigarettes: a systematic review and meta-analysis. Heart, heartjnl-2024-325030. ⁴⁸
13. Yedjou, C. G., et al. (2022). Health effects and known pathology associated with the use of E-cigarettes. Toxicology Reports, 9, 1357-1368. ⁷
14. Zahedi, A., Phandthong, R., et al. (2019). Pulmonary and Cardiovascular Effects of E-cigarette Aerosols: Potential Role of Acquired and Innate Immunity. Current Cardiology Reports, 21(8), 61. ²⁵
15. Zhao, D., et al. (2025). Evidence update on the cancer risk of vaping e-cigarettes: A systematic review. Tobacco Induced Diseases, 23, 10. ⁵⁰

Recent News Articles (Selected Examples, 2024-2025):

1. Associated Press (AP News). (Updated 2024/2025). Hub page covering various vaping news including regulatory actions, youth use trends, and health concerns. ³⁶ (Note: AP News provides ongoing coverage; specific articles from late 2024/early 2025 reflect recent developments.)
2. Dimensions of Dental Hygiene. (Jan 13, 2025). Addressing the Adolescent Vaping Epidemic. ¹³
3. GMU Fourth Estate. (Feb 18, 2025). The Vaping Epidemic: How e-cigarettes are endangering the youth. ⁴⁴
4. Science Focus. (April 2, 2025). Vaping vs cigarettes: Which is worse for your health? ⁶³
5. Yale Medicine News. (June 27, 2024). Researchers Note Latest Vaping Concern: ‘Hacked’ E-Cigarette Devices. ³⁵

Major Health Organizations and Other Key Sources:

• U.S. Centers for Disease Control and Prevention (CDC): Multiple pages and reports on e-cigarette health effects, youth use, chemical components, and guidance. ¹
• Cleveland Clinic: Health information page on vaping risks and treatments. ³
• American Cancer Society: Information on e-cigarettes, vaping, and cancer risk. ²¹
• Truth Initiative: Research and resources on e-cigarettes, youth use, and health effects. ¹²
• American Lung Association: Information on e-cigarette impact on lung health and chemical components. ⁵
• NHS (UK National Health Service) / NHS Inform (Scotland) / NHS Fife: Guidance on vaping, risks, addiction, and use for smoking cessation. ¹⁷
• Cancer Research UK: Information comparing vaping harms to smoking and its role in cessation. ¹⁵
• King’s College London IoPPN Review (Commissioned by UK Gov): Major review on relative harms of vaping vs. smoking. ³⁴
• Americans for Nonsmokers’ Rights (ANSR) / no-smoke.org: Fact sheets on secondhand aerosol and chemical constituents. ²⁴
• Campaign for Tobacco-Free Kids: Advocacy information on youth vaping epidemic and flavored products. ¹⁴
• U.S. Food and Drug Administration (FDA): Data from National Youth Tobacco Survey (NYTS) and regulatory actions. ⁵⁵
• American Medical Association (AMA): Policy statements and resources on the public health epidemic of vaping. ⁴⁵

Works cited

1. Health Effects of Vaping | Smoking and Tobacco Use – CDC, accessed April 8, 2025, https://www.cdc.gov/tobacco/e-cigarettes/health-effects.html
2. Youth Know the Risks: | CDC, accessed April 8, 2025, https://www.cdc.gov/tobacco/basic_information/e-cigarettes/pdfs/Youth-Know-the-Risks-TPs-508_1.pdf
3. Vaping (E-Cigarettes): What It Is, Side Effects & Dangers – Cleveland Clinic, accessed April 8, 2025, https://my.clevelandclinic.org/health/treatments/21162-vaping
4. About E-Cigarettes (Vapes) | Smoking and Tobacco Use – CDC, accessed April 8, 2025, https://www.cdc.gov/tobacco/e-cigarettes/about.html
5. What’s in an E-Cigarette? | American Lung Association, accessed April 8, 2025, https://www.lung.org/quit-smoking/e-cigarettes-vaping/whats-in-an-e-cigarette
6. Health Risks of E-Cigarettes and Vaping – American Lung Association, accessed April 8, 2025, https://www.lung.org/quit-smoking/e-cigarettes-vaping/impact-of-e-cigarettes-on-lung
7. Health effects and known pathology associated with the use of E-cigarettes – PMC, accessed April 8, 2025, https://pmc.ncbi.nlm.nih.gov/articles/PMC9764206/
8. Impact of vaping on respiratory health – PubMed, accessed April 8, 2025, https://pubmed.ncbi.nlm.nih.gov/35851281/
9. Electronic Cigarette Use and the Risk of Cardiovascular Diseases – PMC – PubMed Central, accessed April 8, 2025, https://pmc.ncbi.nlm.nih.gov/articles/PMC9021536/
10. Characterization and Summarization of the Impact of Electronic …, accessed April 8, 2025, https://pubmed.ncbi.nlm.nih.gov/37366450/
11. NIH-funded studies show damaging effects of vaping, smoking on …, accessed April 8, 2025, https://www.nih.gov/news-events/news-releases/nih-funded-studies-show-damaging-effects-vaping-smoking-blood-vessels
12. E-cigarettes: Facts, stats and regulations – Truth Initiative, accessed April 8, 2025, https://truthinitiative.org/research-resources/emerging-tobacco-products/e-cigarettes-facts-stats-and-regulations
13. Addressing the Adolescent Vaping Epidemic – Dimensions of Dental Hygiene, accessed April 8, 2025, https://dimensionsofdentalhygiene.com/article/addressing-the-adolescent-vaping-epidemic/
14. E-Cigarettes: Flavored Products Fuel a Youth Addiction Crisis, accessed April 8, 2025, https://www.tobaccofreekids.org/what-we-do/industry-watch/e-cigarettes
15. Is vaping harmful? | Vaping side effects – Cancer Research UK, accessed April 8, 2025, https://www.cancerresearchuk.org/about-cancer/causes-of-cancer/smoking-and-cancer/is-vaping-harmful
16. Health effects and known pathology associated with the use of E-cigarettes – PubMed, accessed April 8, 2025, https://pubmed.ncbi.nlm.nih.gov/36561957/
17. Vaping addiction soon takes hold | NHS inform, accessed April 8, 2025, https://www.nhsinform.scot/campaigns/vaping/
18. Parents Know the Risks – CDC, accessed April 8, 2025, https://www.cdc.gov/tobacco/basic_information/e-cigarettes/pdfs/Parents-Know-the-Risks-TPs-508.pdf
19. Get the facts about vaping | NHS Fife, accessed April 8, 2025, https://www.nhsfife.org/news-updates/latest-news/2023/12/get-the-facts-about-vaping/
20. Protecting Youth From the Harms of Vaping | Smoking and Tobacco Use – CDC, accessed April 8, 2025, https://www.cdc.gov/tobacco/e-cigarettes/protecting-youth.html
21. E-cigarettes and Vaping | Health Risks of E-cigarettes | American Cancer Society, accessed April 8, 2025, https://www.cancer.org/cancer/risk-prevention/tobacco/e-cigarettes-vaping.html
22. Composition of electronic cigarette aerosol – Wikipedia, accessed April 8, 2025, https://en.wikipedia.org/wiki/Composition_of_electronic_cigarette_aerosol
23. The Chemical Complexity of e-Cigarette Aerosols Compared With the Smoke From a Tobacco Burning Cigarette – PMC – PubMed Central, accessed April 8, 2025, https://pmc.ncbi.nlm.nih.gov/articles/PMC8514950/
24. Electronic Smoking Devices and Secondhand Aerosol – American Nonsmokers’ Rights Foundation | no-smoke.org, accessed April 9, 2025, https://no-smoke.org/electronic-smoking-devices-secondhand-aerosol/
25. Cardiorespiratory and Immunologic Effects of Electronic Cigarettes – PMC, accessed April 8, 2025, https://pmc.ncbi.nlm.nih.gov/articles/PMC7935224/
26. Is vaping better than smoking for cardiorespiratory and muscle function? – PMC, accessed April 8, 2025, https://pmc.ncbi.nlm.nih.gov/articles/PMC7348661/
27. Nicotine: The Good, The Bad & The Ugly | Echelon Health, accessed April 8, 2025, https://www.echelon.health/nicotine-the-good-the-bad-and-the-ugly/
28. Health effects of electronic cigarette (e‑cigarette) use on organ systems and its implications for public health, accessed April 8, 2025, https://pmc.ncbi.nlm.nih.gov/articles/PMC8500897/
29. E-Cigarettes: Use, Effects on Smoking, Risks, and Policy Implications – PMC, accessed April 8, 2025, https://pmc.ncbi.nlm.nih.gov/articles/PMC6251310/
30. no-smoke.org, accessed April 8, 2025, https://no-smoke.org/electronic-smoking-devices-secondhand-aerosol/#:~:text=There%20are%20metals%20in%20ESD,%2C%20nickel%2C%20and%20tin%20nanoparticles.&text=FDA%20scientists%20found%20detectable%20levels,specific%20nitrosamines%20in%20ESD%20aerosol.&text=People%20exposed%20to%20ESD%20aerosol,levels%20comparable%20to%20passive%20smokers.
31. Vaping | Safety, Smoking, Dangers, Pros, Cons, Debate, E-cigarettes, & Tobacco | Britannica, accessed April 8, 2025, https://www.britannica.com/procon/vaping-debate
32. Tobacco News and Updates: Fall 2024, accessed April 8, 2025, https://stopswithme.com/tobacco-news-and-updates-fall-2024/
33. Risk of Heart Attacks Is Double for Daily E-Cigarette Users, accessed April 8, 2025, https://tobacco.ucsf.edu/risk-heart-attacks-double-daily-e-cigarette-users
34. Vaping substantially less harmful than smoking, largest review of its …, accessed April 8, 2025, https://www.kcl.ac.uk/news/vaping-substantially-less-harmful-than-smoking-largest-review-of-its-kind-finds
35. Researchers Note Latest Vaping Concern: ‘Hacked’ E-Cigarette Devices – Yale Medicine, accessed April 8, 2025, https://www.yalemedicine.org/news/teen-vaping
36. Study suggests e-cigarette flavorings may pose heart risk – AP News, accessed April 8, 2025, https://apnews.com/article/8bf7e4cfd83f4f02ad1b6a02eac41ef1
37. Assessment of Respiratory Health Implications of Vaping: A …, accessed April 8, 2025, https://pubmed.ncbi.nlm.nih.gov/39398779/
38. E-cigarette use and respiratory symptoms in adults: A systematic review and meta-analysis, accessed April 8, 2025, https://pmc.ncbi.nlm.nih.gov/articles/PMC10720266/
39. E-Cigarettes and Cardiopulmonary Health: Review for Clinicians | Circulation – AHA Journals, accessed April 8, 2025, https://www.ahajournals.org/doi/10.1161/CIRCULATIONAHA.121.056777
40. A surgeon general report once cleared the air about smoking. Is it time for one on vaping?, accessed April 8, 2025, https://apnews.com/article/smoking-vaping-surgeon-general-db81e873c256e38433734e86d6a50f7e
41. Vaping statistics & facts 2024 | SingleCare, accessed April 8, 2025, https://www.singlecare.com/blog/news/vaping-statistics/
42. Health officials identify ‘strong culprit’ in vaping illnesses | PBS News, accessed April 8, 2025, https://www.pbs.org/newshour/health/health-officials-identify-strong-culprit-in-vaping-illnesses
43. pmc.ncbi.nlm.nih.gov, accessed April 8, 2025, https://pmc.ncbi.nlm.nih.gov/articles/PMC10952413/#:~:text=The%20published%20evidence%20indicates%20that,E%20acetate%E2%80%90containing%20products).
44. The vaping epidemic | Fourth Estate, accessed April 8, 2025, https://gmufourthestate.com/2025/02/18/the-vaping-epidemic/
45. E-cigarettes and vaping: A public health epidemic | American Medical Association, accessed April 8, 2025, https://www.ama-assn.org/delivering-care/public-health/e-cigarettes-and-vaping-public-health-epidemic
46. E-Cigarettes and Respiratory Disease: A Replication, Extension, and Future Directions – National Bureau of Economic Research, accessed April 8, 2025, https://www.nber.org/system/files/working_papers/w27507/w27507.pdf
47. First long-term study finds e-cigarettes significantly increase the risk of chronic lung disease, accessed April 8, 2025, https://www.nhlbi.nih.gov/news/2019/first-long-term-study-finds-e-cigarettes-significantly-increase-risk-chronic-lung-disease
48. Cardiovascular health effects of vaping e-cigarettes: a systematic …, accessed April 8, 2025, https://pubmed.ncbi.nlm.nih.gov/40010935/
49. Characterization and Summarization of the Impact of Electronic Cigarettes on the Cardiovascular System: A Systematic Review and Meta-Analysis, accessed April 8, 2025, https://pmc.ncbi.nlm.nih.gov/articles/PMC10290866/
50. Evidence update on the cancer risk of vaping e-cigarettes: A …, accessed April 8, 2025, https://www.tobaccoinduceddiseases.org/Evidence-update-on-the-cancer-risk-of-vaping-e-cigarettes-A-systematic-review,192934,0,2.html
51. Using e-cigarettes to stop smoking – NHS, accessed April 8, 2025, https://www.nhs.uk/live-well/quit-smoking/using-e-cigarettes-to-stop-smoking/
52. Vaping in children and teens: smoke without fire? – Senedd Research, accessed April 8, 2025, https://research.senedd.wales/research-articles/vaping-in-children-and-teens-smoke-without-fire/
53. Protect children from vapes epidemic, doctors urge government – BBC News, accessed April 8, 2025, https://feeds.bbci.co.uk/news/articles/cq82dlv1g3lo
54. Youth E-Cigarette Use Drops to Lowest Level in a Decade – CDC, accessed April 8, 2025, https://www.cdc.gov/media/releases/2024/p0905-youth-ecigarette.html
55. Results from the Annual National Youth Tobacco Survey – FDA, accessed April 8, 2025, https://www.fda.gov/tobacco-products/youth-and-tobacco/results-annual-national-youth-tobacco-survey
56. Believe It or Not, 1 Vape has 20 Cigarettes Worth of Nicotine | UC San Francisco, accessed April 8, 2025, https://www.ucsf.edu/news/2024/12/429131/believe-it-or-not-1-vape-has-20-cigarettes-worth-nicotine
57. ‘Many failures’: Whistleblower exposes how fired Biden-era official was soft on China, prioritized DEI – WFIN Local News, accessed April 8, 2025, https://wfin.com/fox-political-news/many-failures-whistleblower-exposes-how-fired-biden-era-official-was-soft-on-china-prioritized-dei/
58. Vaping: What are the medical impacts? – BBC News – YouTube, accessed April 8, 2025, https://www.youtube.com/watch?v=ygxMr2AE_bc&pp=0gcJCfcAhR29_xXO
59. Vaping myths and the facts – Better Health – NHS, accessed April 8, 2025, https://www.nhs.uk/better-health/quit-smoking/ready-to-quit-smoking/vaping-to-quit-smoking/vaping-myths-and-the-facts/
60. How a debate over vaping might derail the war on tobacco | AP News, accessed April 8, 2025, https://apnews.com/article/vaping-debate-philanthropy-smoke-free-1ae3a5d6aa29962bb82281e128cc4e76
61. Long-term effects of chronic exposure to electronic cigarette aerosol on the cardiovascular and pulmonary system in mice: A comparative study to cigarette smoke – PubMed, accessed April 8, 2025, https://pubmed.ncbi.nlm.nih.gov/38508052/
62. Predicting the long-term effects of electronic cigarette use on population health: a systematic review of modelling studies – PubMed, accessed April 8, 2025, https://pubmed.ncbi.nlm.nih.gov/37295941/
63. Is smoking or vaping worse for you? It depends who’s asking, accessed April 8, 2025, https://www.sciencefocus.com/news/vapes-cigarettes-health
64. Vaping – AP News, accessed April 8, 2025, https://apnews.com/hub/vaping
65. FDA tobacco official is removed from post in latest blow to health agency’s leadership, accessed April 8, 2025, https://apnews.com/article/fda-tobacco-rfk-brian-king-cf2d5657e5d55410073aece19592be09
66. Perceptions of Harm to Children Exposed to Secondhand Aerosol From Electronic Vapor Products, Styles Survey, 2015 – PMC, accessed April 9, 2025, https://pmc.ncbi.nlm.nih.gov/articles/PMC5538867/
67. Exposure to Secondhand Smoke and Secondhand E-Cigarette Aerosol Among Middle and High School Students – CDC, accessed April 9, 2025, https://www.cdc.gov/pcd/issues/2019/18_0531.htm
68. Use of electronic cigarettes and secondhand exposure to their aerosols are associated with asthma symptoms among adolescents: a cross-sectional study – PMC, accessed April 9, 2025, https://pmc.ncbi.nlm.nih.gov/articles/PMC7670675/
69. In secondhand vape, scientists smell risk – American Heart Association, accessed April 9, 2025, https://www.heart.org/en/news/2022/05/31/in-secondhand-vape-scientists-smell-risk
70. E-Cigarette and Environment – MDPI, accessed April 9, 2025, https://www.mdpi.com/2076-3298/12/3/72
71. 18.6.9 Exposure to secondhand e-cigarette emissions – Tobacco in Australia, accessed April 9, 2025, https://www.tobaccoinaustralia.org.au/chapter-18-e-cigarettes/18-6-the-health-effects-of-e-cigarette-use/18-6-9-exposure-to-secondhand-e-cigarette-emissions
72. Transport and Mitigation of Exhaled Electronic Cigarette Aerosols in a Multizone Indoor Environment, accessed April 9, 2025, https://aaqr.org/articles/aaqr-20-03-oa-0088
73. Effects of Electronic Cigarettes on Indoor Air Quality and Health – PMC, accessed April 9, 2025, https://pmc.ncbi.nlm.nih.gov/articles/PMC7346849/
74. Impacts of electronic cigarettes usage on air quality of vape shops and their nearby areas – PMC – PubMed Central, accessed April 9, 2025, https://pmc.ncbi.nlm.nih.gov/articles/PMC7937385/
75. Particulate Matter from Electronic Cigarettes and Conventional Cigarettes: a Systematic Review and Observational Study, accessed April 9, 2025, http://tobacco.cleartheair.org.hk/wp-content/uploads/2016/06/art%253A10.1007%252Fs40572-015-0072-x.pdf
76. Characteristics of secondhand electronic cigarette aerosols from active human use, accessed April 9, 2025, https://www.tandfonline.com/doi/full/10.1080/02786826.2017.1355548
77. Particulate matter in aerosols produced by two last generation electronic cigarettes: a comparison in a real-world environment | Pulmonology, accessed April 9, 2025, https://www.journalpulmonology.org/en-particulate-matter-in-aerosols-produced-articulo-S2531043721000799
78. Environmental and individual exposure to secondhand aerosol of electronic cigarettes in confined spaces: Results from the TackSHS Project† – PubMed, accessed April 9, 2025, https://pubmed.ncbi.nlm.nih.gov/33905602/
79. Secondhand electronic cigarette aerosol in vehicles impacts indoor air quality – PMC, accessed April 9, 2025, https://pmc.ncbi.nlm.nih.gov/articles/PMC10528711/
80. Effects of exposure to direct and secondhand hookah and e-cigarette aerosols on ambient air quality and cardiopulmonary health in adults and children: protocol for a panel study, accessed April 9, 2025, https://pmc.ncbi.nlm.nih.gov/articles/PMC6597628/
81. Exposure to secondhand aerosol from electronic cigarettes at homes: A real-life study in four European countries – PubMed, accessed April 9, 2025, https://pubmed.ncbi.nlm.nih.gov/36099951/
82. Indoor Air Quality and Passive E-cigarette Aerosol Exposures in Vape-Shops – PMC, accessed April 9, 2025, https://pmc.ncbi.nlm.nih.gov/articles/PMC7542645/
83. Secondhand Nicotine Absorption From E-Cigarette Vapor vs Tobacco Smoke in Children, accessed April 9, 2025, https://pubmed.ncbi.nlm.nih.gov/38990571/
84. Secondhand Exposure to Vapors From Electronic Cigarettes – PMC, accessed April 9, 2025, https://pmc.ncbi.nlm.nih.gov/articles/PMC4565991/
85. Secondhand Nicotine Absorption From E-Cigarette Vapor vs Tobacco Smoke in Children, accessed April 9, 2025, https://pmc.ncbi.nlm.nih.gov/articles/PMC11240186/
86. Identification and Quantification of Electronic Cigarette Exhaled Aerosol Residue Chemicals in Field Sites – PubMed Central, accessed April 9, 2025, https://pmc.ncbi.nlm.nih.gov/articles/PMC6410739/
87. Secondhand nicotine vaping at home and respiratory symptoms in young adults | Thorax, accessed April 9, 2025, https://thorax.bmj.com/content/77/7/663
88. Secondhand Exposure to Aerosols From Electronic Nicotine Delivery Systems and Asthma Exacerbations Among Youth With Asthma – PubMed, accessed April 9, 2025, https://pubmed.ncbi.nlm.nih.gov/30359612/
89. Secondhand Exposure to Aerosols From Electronic Nicotine Delivery Systems and Asthma Exacerbations Among Youth With Asthma – PMC – PubMed Central, accessed April 9, 2025, https://pmc.ncbi.nlm.nih.gov/articles/PMC6688978/
90. E-Cigarettes and Asthma: Health Effects of Vaping and Asthma, accessed April 9, 2025, https://allergyasthmanetwork.org/what-is-asthma/e-cigarettes-and-asthma/
91. Health Problems Caused by Secondhand Smoke | Smoking and Tobacco Use – CDC, accessed April 9, 2025, https://www.cdc.gov/tobacco/secondhand-smoke/health.html
92. Tobacco Smoke, Vaping, and Asthma | AAFA.org, accessed April 9, 2025, https://aafa.org/asthma/asthma-triggers-causes/secondhand-smoke-environmental-tobacco-asthma/
93. Second-hand vape smoke linked to more asthma symptoms in kids – News-Medical, accessed April 9, 2025, https://www.news-medical.net/news/20240320/Second-hand-vape-smoke-linked-to-more-asthma-symptoms-in-kids.aspx
94. Association between Second-Hand Exposure to E-Cigarettes at Home and Exacerbations in Children with Asthma – PMC, accessed April 9, 2025, https://pmc.ncbi.nlm.nih.gov/articles/PMC10969563/
95. Secondhand smoke and secondhand aerosol – Truth Initiative, accessed April 9, 2025, https://truthinitiative.org/research-resources/harmful-effects-tobacco/secondhand-smoke-and-secondhand-aerosol
96. Secondhand Smoke and Asthma Triggers | Vermont Department of Health, accessed April 9, 2025, https://www.healthvermont.gov/wellness/asthma-lung-disease/secondhand-smoke-and-asthma-triggers
97. Secondhand Electronic-Cigarette Aerosol and Indoor Air Quality | US EPA, accessed April 9, 2025, https://www.epa.gov/indoor-air-quality-iaq/secondhand-electronic-cigarette-aerosol-and-indoor-air-quality