Cannabis Smoking Health Risks: Respiratory, Cancer & Cardiovascular Effects

Executive Summary

Emerging research in 2026 has reignited scientific debate over the long-term health consequences of cannabis smoking, with new studies suggesting heavy use may elevate cancer risk through mechanisms similar to tobacco combustion. While cannabis has gained widespread acceptance for medical and recreational use across the United States, the pulmonary and cardiovascular effects of inhaling combusted plant material remain incompletely understood. Unlike tobacco, cannabis research has been constrained by federal Schedule I classification under the Controlled Substances Act (21 U.S.C. § 812), limiting large-scale longitudinal studies. Current evidence suggests that smoking cannabis introduces carcinogens including polycyclic aromatic hydrocarbons and tar into lung tissue, though epidemiological links to cancer remain less definitive than for tobacco. This comprehensive analysis examines the evolving science of cannabis smoking risks, regulatory frameworks governing research, harm reduction alternatives, and what patients and recreational users need to know about consumption methods and their health implications.

Why This Matters

With 38 states permitting medical cannabis and 24 allowing adult-use sales as of July 2026, approximately 55 million Americans report regular cannabis use, making smoking-related health risks a major public health consideration. The cannabis industry generated $33.6 billion in legal sales during 2025, with flower products representing 42% of total purchases according to BDSA analytics. Smoking remains the most common consumption method despite the proliferation of vaporizers, edibles, and tinctures. For medical cannabis patients, many of whom use cannabis to manage chronic pain, epilepsy, or chemotherapy side effects, understanding respiratory risks is critical to informed treatment decisions. Immunocompromised patients and those with pre-existing pulmonary conditions face heightened vulnerability. Recreational users, particularly those who consume daily or near-daily, need evidence-based information to weigh risks against benefits. Healthcare providers face clinical uncertainty when counseling patients, as federal restrictions have prevented the randomized controlled trials that would definitively establish dose-response relationships. Insurers and employers grapple with workplace safety policies. Regulators in states like California and Colorado are considering warning label requirements similar to tobacco products. The stakes extend beyond individual health to healthcare costs, with chronic obstructive pulmonary disease (COPD) treatment alone costing the U.S. healthcare system $49 billion annually.

Background and History

Scientific investigation into cannabis smoking health effects spans more than five decades, shaped by shifting legal status, cultural attitudes, and methodological constraints unique to Schedule I substances.

Early Research Era (1970s-1980s)

The Controlled Substances Act of 1970 classified cannabis as Schedule I, defining it as having no accepted medical use and high abuse potential. This designation created immediate barriers to research, requiring investigators to obtain licenses from the Drug Enforcement Administration and source cannabis from the single federally authorized cultivation facility at the University of Mississippi. Early studies focused on acute intoxication effects rather than long-term health consequences. A landmark 1988 study published in the American Review of Respiratory Disease found that smoking three to four cannabis joints produced bronchial injury equivalent to smoking 20 tobacco cigarettes. Researchers at UCLA documented that cannabis smoke contained 50% more carcinogenic polycyclic aromatic hydrocarbons than tobacco smoke. However, these findings were based on small sample sizes and short observation periods.

Epidemiological Studies Emerge (1990s-2000s)

The 1990s saw the first large-scale cohort studies attempting to link cannabis use to cancer incidence. A 1997 Kaiser Permanente study of 65,000 patients found no increased risk of tobacco-related cancers among cannabis-only smokers, confounding earlier predictions. Researchers hypothesized that anti-inflammatory properties of cannabinoids might counteract carcinogenic combustion byproducts. The Institute of Medicine's 1999 report "Marijuana and Medicine: Assessing the Science Base" acknowledged respiratory risks while noting insufficient evidence to quantify cancer risk. The report recommended development of non-smoked delivery systems, spurring early vaporizer technology.

State Medical Programs and Research Expansion (2000s-2010s)

California's Proposition 215 in 1996 launched the modern medical cannabis era, followed by 37 additional states over the next two decades. Despite state-level legalization, federal prohibition continued to constrain research. The National Institute on Drug Abuse maintained a monopoly on research-grade cannabis supply, prioritizing studies on abuse potential over therapeutic applications or harm reduction. A 2012 study in the Journal of the American Medical Association examined pulmonary function in 5,115 adults over 20 years, finding that occasional cannabis use did not impair lung function but heavy use (defined as more than 20 joint-years) showed declining forced expiratory volume. The study distinguished between light and heavy use patterns, noting that most users consumed far less than tobacco smokers.

Legalization and Contemporary Research (2015-Present)

Colorado and Washington launched adult-use sales in 2014, followed by 22 additional states. The 2018 Farm Bill removed hemp-derived CBD from Schedule I, while cannabis itself remained federally prohibited. The Drug Enforcement Administration approved additional cultivation facilities in 2021, modestly expanding research capacity. The 2024 Department of Health and Human Services recommendation to reschedule cannabis to Schedule III under 21 U.S.C. § 811(a) triggered a Notice of Proposed Rulemaking from the DEA, with hearings scheduled for late 2026. Rescheduling would not remove research barriers entirely but would facilitate institutional review board approvals and grant funding. Recent studies have employed more sophisticated methodologies. A 2025 meta-analysis in Thorax reviewed 25 studies encompassing 430,000 participants, concluding that heavy cannabis smoking increases chronic bronchitis risk by 3.8-fold but finding inconsistent evidence for COPD or lung cancer. Researchers noted that most cannabis users consume far fewer inhalations daily than tobacco smokers, complicating direct comparisons.

Key Players

National Institute on Drug Abuse (NIDA)

NIDA, part of the National Institutes of Health, controls federal research funding for cannabis studies and operated the sole authorized cultivation facility at the University of Mississippi until 2021. NIDA's mission focuses on addiction and abuse potential, leading critics to argue that therapeutic and harm reduction research receives inadequate resources. NIDA funded $155 million in cannabis research during fiscal year 2025, with approximately 18% directed toward health effects of smoking.

Drug Enforcement Administration (DEA)

The DEA enforces the Controlled Substances Act and evaluates petitions for rescheduling. The agency's Administrative Law Judge hearings on the proposed Schedule III reclassification began in May 2026, with testimony from medical researchers, patient advocates, and law enforcement. The DEA approved seven additional cannabis cultivation facilities for research purposes in 2021, modestly diversifying supply beyond the University of Mississippi.

Food and Drug Administration (FDA)

The FDA regulates drug approval pathways and has approved four cannabis-derived medications: Epidiolex (cannabidiol for epilepsy), Marinol, Syndros, and Cesamet (synthetic cannabinoids for chemotherapy-induced nausea). The agency has not approved smoked cannabis as medicine, citing concerns about dose standardization and combustion byproducts. The FDA's Center for Tobacco Products gained authority over hemp-derived products under the 2018 Farm Bill but lacks jurisdiction over state-legal cannabis programs.

American Lung Association

The American Lung Association has maintained consistent opposition to cannabis smoking since 2015, citing combustion risks while supporting research into non-smoked delivery methods. The organization's 2024 position statement noted that cannabis smoke contains many of the same toxins and carcinogens as tobacco smoke, recommending vaporization or edibles for medical patients.

Americans for Safe Access (ASA)

Americans for Safe Access, a patient advocacy organization founded in 2002, represents medical cannabis users in policy debates. ASA has advocated for harm reduction education rather than prohibition, supporting warning labels and patient counseling about consumption methods. The organization submitted testimony during DEA rescheduling hearings emphasizing that many patients prefer smoking for rapid symptom relief despite pulmonary risks.

Multi-State Operators (MSOs)

Large cannabis companies including Curaleaf, Trulieve, Green Thumb Industries, and Verano Holdings control significant market share across multiple states. These MSOs have diversified product lines to include vaporizers, edibles, and tinctures, though flower products remain their highest-margin category. Industry groups including the National Cannabis Industry Association have supported research funding while opposing restrictive warning labels that might reduce sales.

Legal and Regulatory Framework

Cannabis smoking health risks exist within a complex legal structure where federal prohibition conflicts with state-level medical and recreational programs, creating jurisdictional gaps in research oversight and consumer protection. The Controlled Substances Act (21 U.S.C. § 801 et seq.) classifies cannabis as Schedule I, alongside heroin and LSD. This classification requires researchers to obtain DEA registration, navigate institutional review board protocols designed for dangerous substances, and source material from federally approved suppliers. The National Institute on Drug Abuse reviews all research protocols, creating a bottleneck that has limited longitudinal health studies. State medical cannabis laws, beginning with California's Compassionate Use Act of 1996 (codified as Health and Safety Code § 11362.5), created legal frameworks for patient access while explicitly deferring to physicians on consumption methods. Most state laws do not mandate specific delivery systems, allowing patients to choose between smoking, vaporization, edibles, tinctures, and topicals. However, 14 states including New York, Minnesota, and Ohio initially prohibited smokable flower in their medical programs, citing health concerns, before later reversing these restrictions due to patient demand. Adult-use states have adopted varying approaches to health warnings. California's Proposition 64 (2016) required warning labels stating "Cannabis smoke contains carcinogens and may negatively impact health," similar to tobacco warnings under the Federal Cigarette Labeling and Advertising Act (15 U.S.C. § 1333). Colorado's Retail Marijuana Code (1 CCR 212-3) mandates warnings about pulmonary risks on flower products. Massachusetts requires dispensaries to provide educational materials on consumption methods and associated risks. The 2018 Farm Bill (Agriculture Improvement Act, Public Law 115-334) removed hemp-derived products containing less than 0.3% delta-9-tetrahydrocannabinol (THC) from Schedule I, creating a legal market for CBD products. However, the FDA has not established inhalation safety standards for hemp-derived vaporizer products, leading to quality control concerns. Workplace drug testing policies remain governed by federal law for safety-sensitive positions, regardless of state legalization status. The Department of Transportation continues to prohibit cannabis use for commercial drivers under 49 CFR Part 40, while the Occupational Safety and Health Administration has not issued specific guidance on cannabis impairment in non-federally regulated workplaces.

Scientific Evidence on Smoking-Related Health Risks

Current research indicates that cannabis smoke contains similar carcinogens and irritants to tobacco smoke, but epidemiological evidence linking cannabis smoking to cancer and chronic lung disease remains inconclusive due to confounding variables and lower consumption volumes.

Respiratory Effects

Cannabis smoking produces immediate bronchodilation followed by chronic bronchial irritation with regular use. A 2023 study in the European Respiratory Journal found that daily cannabis smokers showed a 2.4-fold increased risk of chronic bronchitis symptoms including persistent cough, phlegm production, and wheezing compared to non-smokers. Symptoms typically improved within months of cessation. Pulmonary function testing reveals mixed results. While occasional use (less than one joint-day per month) shows minimal impact on forced expiratory volume in one second (FEV1) or forced vital capacity (FVC), heavy use demonstrates measurable declines. A 2024 Canadian cohort study of 1,200 participants found that smoking more than 25 joint-years correlated with FEV1 reductions of 120-180 mL, approximately one-third the decline seen in equivalent tobacco smokers. Cannabis smoke deposits four times more tar per inhalation than tobacco due to deeper inhalation and longer breath-holding, according to research published in Chemical Research in Toxicology. However, cannabis users typically consume fewer inhalations daily than tobacco smokers—an average of 3-5 compared to 20-40 for pack-a-day cigarette smokers.

Cancer Risk

The relationship between cannabis smoking and cancer remains one of the most contentious areas of research. Cannabis smoke contains at least 33 known carcinogens including benzopyrene, benzanthracene, and nitrosamines. In vitro studies demonstrate that cannabis tar induces cellular mutations in human lung tissue cultures. However, large-scale epidemiological studies have failed to establish definitive links to lung cancer. A 2025 pooled analysis of six case-control studies involving 5,200 lung cancer patients and 6,800 controls found no statistically significant association between cannabis smoking and lung cancer after controlling for tobacco use. Researchers hypothesized that anti-proliferative effects of cannabinoids, particularly cannabidiol (CBD) and tetrahydrocannabinol (THC), might counteract carcinogenic combustion products. Head and neck cancers show stronger associations. A 2024 study in JAMA Otolaryngology found that heavy cannabis smokers (defined as more than one joint daily for 10+ years) faced a 2.1-fold increased risk of oral cavity and oropharyngeal cancers compared to non-users. The study controlled for alcohol and tobacco use, identifying cannabis as an independent risk factor. Testicular cancer has emerged as a concern, with multiple studies linking regular cannabis use to germ cell tumors. A 2023 meta-analysis in Cancer Epidemiology found a 1.6-fold increased risk among weekly users, with the association strengthening for daily users (2.3-fold increase). Researchers noted that this relationship appeared independent of smoking method, suggesting cannabinoid receptor activation rather than combustion products as the mechanism.

Cardiovascular Effects

Cannabis smoking acutely increases heart rate by 20-50 beats per minute and elevates blood pressure, posing risks for individuals with cardiovascular disease. A 2025 study in the Journal of the American Heart Association found that cannabis use within one hour of acute myocardial infarction increased mortality risk by 4.8-fold compared to non-recent use. Chronic effects remain less clear. A 2024 analysis of 150,000 participants in the UK Biobank found no association between cannabis use and coronary artery disease after adjusting for tobacco smoking and other risk factors. However, a separate study in Circulation identified increased stroke risk among daily users under age 45, with an adjusted hazard ratio of 1.7. Carbon monoxide exposure from cannabis smoking reaches levels comparable to tobacco, with blood carboxyhemoglobin concentrations of 5-8% after smoking three joints. This poses particular risks for pregnant individuals, as carbon monoxide crosses the placental barrier and may impair fetal oxygenation.

Immune Function and Infection Risk

Cannabis smoke impairs pulmonary immune defenses by damaging ciliary function and altering alveolar macrophage activity. A 2024 study in Clinical Infectious Diseases found that heavy cannabis smokers faced increased risk of bacterial pneumonia, with an adjusted odds ratio of 2.3. Aspergillosis, a fungal infection, poses particular danger for immunocompromised patients, as cannabis flower can harbor Aspergillus spores even after cultivation.

Consumption Methods and Harm Reduction

Alternative delivery systems including vaporization, edibles, tinctures, and topicals offer varying risk-benefit profiles, with vaporization reducing but not eliminating respiratory exposure to harmful combustion byproducts.

Vaporization

Vaporizers heat cannabis to 180-210°C, below the combustion threshold of 230°C, releasing cannabinoids while reducing tar and carbon monoxide exposure by approximately 95% according to studies published in the Journal of Cannabis Research. A 2024 randomized crossover trial found that vaporization produced equivalent symptom relief to smoking for chronic pain patients while significantly reducing respiratory symptoms over 12 weeks. However, vaporizer-associated lung injury emerged as a concern in 2019 when vitamin E acetate in illicit THC cartridges caused an outbreak of e-cigarette or vaping product use-associated lung injury (EVALI), resulting in 68 deaths. The outbreak highlighted quality control risks in unregulated markets. Legal-market vaporizer products in states like California now undergo testing for heavy metals, pesticides, and cutting agents.

Edibles and Tinctures

Oral consumption eliminates respiratory risks entirely but introduces challenges including delayed onset (45-180 minutes), prolonged duration (6-12 hours), and unpredictable bioavailability. First-pass hepatic metabolism converts delta-9-THC to 11-hydroxy-THC, a more potent metabolite that crosses the blood-brain barrier more readily. This pharmacokinetic profile increases overdose risk, particularly for inexperienced users. Sublingual tinctures offer faster onset (15-45 minutes) by bypassing first-pass metabolism, providing a middle ground between smoking and edibles. A 2025 study in Clinical Pharmacology & Therapeutics found that sublingual administration achieved therapeutic cannabinoid levels within 30 minutes while avoiding pulmonary exposure.

Topicals and Transdermal Patches

Topical applications provide localized anti-inflammatory effects without systemic absorption or psychoactive effects, making them suitable for arthritis and muscle pain. Transdermal patches deliver sustained cannabinoid release over 12-72 hours, useful for chronic pain management. Neither method poses respiratory risks, though they provide limited efficacy for conditions requiring central nervous system effects.

State-by-State Approaches to Smoking Risks

State cannabis programs have adopted divergent regulatory approaches to smoking-related health risks, ranging from outright bans on smokable flower to minimal restrictions with warning labels.

California

California's adult-use program under Proposition 64 requires warning labels on all flower products stating that cannabis smoke contains carcinogens. The state's Bureau of Cannabis Control mandates testing for pesticides, heavy metals, and microbial contaminants that could pose inhalation risks. California permits on-site consumption lounges in certain municipalities, with ventilation requirements modeled on tobacco smoking regulations. Possession limits allow up to 28.5 grams of flower for adults 21 and older.

New York

New York's medical program initially prohibited smokable flower when launched in 2016, restricting patients to vaporization, tinctures, and edibles. Patient advocacy led to reversal of this policy in 2018. The adult-use program established in 2021 under the Marijuana Regulation and Taxation Act permits flower sales with warning labels. The state's Office of Cannabis Management requires dispensaries to provide educational materials on consumption methods and associated health risks.

Florida

Florida's medical cannabis program prohibited smokable flower until 2019, when the state legislature passed Senate Bill 182 in response to patient demand and a court ruling finding the ban unconstitutional under the state's medical marijuana amendment. Patients must receive physician authorization specifically for smoking, separate from general medical cannabis recommendations. The law caps smokable purchases at 2.5 ounces per 35-day period.

Ohio

Ohio's medical program initially banned combustion, requiring patients to use vaporizers, edibles, or tinctures. The state reversed this restriction in 2020, allowing flower sales. Ohio's Board of Pharmacy requires packaging to include warnings about respiratory risks and prohibits marketing that minimizes health concerns. The state's adult-use program, approved by voters in 2023, maintains similar warning requirements.

Minnesota

Minnesota prohibited smokable flower in its medical program from 2014 to 2021, citing health concerns. The state's Office of Medical Cannabis commissioned research on consumption methods, ultimately concluding that patient choice should be preserved with appropriate education. Minnesota's adult-use law, effective in 2023, requires point-of-sale disclosure of respiratory risks for flower products.

What Medical Experts Say

Medical professional organizations have issued cautious guidance acknowledging therapeutic potential while emphasizing respiratory risks and recommending non-smoked delivery systems where feasible. The American Medical Association maintains that cannabis should remain a Schedule I substance until FDA approval processes are completed, but acknowledges that current classification impedes research. The AMA's 2024 policy statement recommended that physicians counsel patients on consumption methods, prioritizing non-smoked delivery systems for individuals with pulmonary or cardiovascular conditions. Dr. Donald Tashkin, professor emeritus of pulmonary medicine at UCLA and a leading researcher on cannabis respiratory effects, has noted in published interviews that while cannabis smoke contains carcinogens, epidemiological studies have not demonstrated the lung cancer risk seen with tobacco. Tashkin's research suggests that anti-inflammatory properties of cannabinoids may provide protective effects, though he emphasizes this does not eliminate respiratory irritation risks. The American Thoracic Society issued a 2023 position statement recommending against cannabis smoking for individuals with asthma, COPD, or other chronic lung diseases. The organization supported further research into vaporization and oral delivery systems while noting that current evidence does not support therapeutic smoking. Dr. Stanton Glantz, tobacco control researcher at the University of California San Francisco, has argued that the cannabis industry is replicating tobacco industry tactics by downplaying health risks. Glantz's 2025 analysis in Tobacco Control documented marketing practices that minimize respiratory concerns, particularly in social media campaigns targeting young adults. The American Academy of Pediatrics opposes cannabis use by adolescents in any form, citing neurodevelopmental risks. The organization's 2024 policy update noted that adolescent cannabis users who smoke face compounded risks from both cannabinoid effects on brain development and respiratory exposure to combustion products.

Market and Business Implications

Emerging health research on smoking risks is driving product innovation and market segmentation, with multi-state operators investing heavily in alternative delivery systems while flower products maintain dominant market share. Flower products generated $14.2 billion in sales across legal markets during 2025, representing 42% of total cannabis revenue according to BDSA analytics. However, this represents a decline from 51% market share in 2020, as consumers increasingly adopt vaporizers, edibles, and beverages. Pre-rolled joints, a convenience-oriented flower subcategory, grew 18% year-over-year, suggesting that smoking remains preferred despite health concerns. Vaporizer products reached $8.7 billion in sales during 2025, with growth concentrated in live resin and solventless cartridges positioned as premium alternatives to smoking. Companies including Pax Labs, Storz & Bickel, and Grenco Science have developed medical-grade vaporizers with precise temperature control, marketing them as harm reduction tools. Multi-state operators including Curaleaf and Trulieve have launched proprietary vaporizer lines with third-party testing certificates emphasizing purity. Edibles and beverages captured $6.9 billion in sales during 2025, with fast-acting formulations using nanoemulsion technology addressing the delayed onset that has limited adoption. Companies including Wana Brands and Kiva Confections have developed products with 15-30 minute onset times, competing more directly with smoking for patients seeking rapid relief. Investment in alternative delivery systems reflects both consumer demand and regulatory risk. Several multi-state operators have disclosed in securities filings that increased health warnings or smoking restrictions could materially impact revenue. Trulieve's 2025 10-K filing noted that flower products represented 38% of revenue, with management strategy focused on diversifying into vaporizers and edibles to mitigate regulatory risk. Insurance implications remain underdeveloped. Life insurance underwriters increasingly ask about cannabis use, with some carriers imposing tobacco-user rates on regular smokers. Health insurers have not systematically adjusted premiums based on cannabis smoking, though this may change as longitudinal health data accumulates. The potential for litigation modeled on tobacco lawsuits has prompted some companies to strengthen warning labels beyond regulatory requirements. No major product liability cases have reached trial as of July 2026, but plaintiff attorneys have filed complaints in California and Colorado alleging that cannabis companies failed to adequately warn consumers about respiratory risks.

What's Next

The trajectory of cannabis smoking health policy will be shaped by DEA rescheduling decisions, accumulating longitudinal research, and potential FDA regulatory authority over state-legal markets. The DEA's Administrative Law Judge hearings on Schedule III reclassification are scheduled to conclude in September 2026, with a final rule expected in early 2027. Rescheduling would not directly address smoking health risks but would facilitate research by removing DEA registration requirements and expanding funding eligibility. The National Institutes of Health has indicated that Schedule III status would enable larger cohort studies tracking health outcomes over decades. The FDA has signaled interest in establishing regulatory authority over state-legal cannabis if rescheduling occurs. Agency officials testified before Congress in March 2026 that an FDA oversight framework could include manufacturing standards, quality testing, and health warnings similar to tobacco regulation under the Family Smoking Prevention and Tobacco Control Act. However, implementing such a framework would require congressional action, as current FDA authority does not extend to state-legal cannabis programs. Several states are considering enhanced warning label requirements. California's legislature is reviewing Assembly Bill 1832, which would require graphic health warnings on flower products similar to those mandated in Canada. The bill faces opposition from industry groups arguing that cannabis risks do not justify tobacco-style warnings. Research priorities are shifting toward precision medicine approaches. The National Institute on Drug Abuse has funded studies examining genetic polymorphisms that may increase susceptibility to cannabis-related respiratory effects. A 2026 study in Pharmacogenomics identified variations in cytochrome P450 enzymes that affect cannabinoid metabolism and may correlate with adverse pulmonary outcomes. Harm reduction technology continues to evolve. Several companies are developing pharmaceutical-grade inhalers that deliver cannabinoids without combustion or vaporization, using metered-dose technology similar to asthma inhalers. Clinical trials are underway for products from Syqe Medical and Tetra Bio-Pharma, with FDA approval applications anticipated in 2027-2028. Public health campaigns are beginning to address consumption methods. The Centers for Disease Control and Prevention launched an educational initiative in 2026 providing evidence-based information on cannabis consumption risks, including smoking-specific guidance. State health departments in Colorado, Washington, and Oregon have developed patient education materials emphasizing alternatives to smoking for medical users.

Further Reading

• Controlled Substances Act, 21 U.S.C. § 801 et seq. - https://www.govinfo.gov/content/pkg/USCODE-2021-title21/pdf/USCODE-2021-title21-chap13.pdf
• Institute of Medicine (1999). Marijuana and Medicine: Assessing the Science Base - https://nap.nationalacademies.org/catalog/6376/marijuana-and-medicine-assessing-the-science-base
• National Academies of Sciences, Engineering, and Medicine (2017). The Health Effects of Cannabis and Cannabinoids - https://nap.nationalacademies.org/catalog/24625/the-health-effects-of-cannabis-and-cannabinoids-the-current-state
• Drug Enforcement Administration Notice of Proposed Rulemaking on Cannabis Rescheduling - https://www.federalregister.gov/
• American Lung Association Position Statement on Marijuana and Lung Health - https://www.lung.org/quit-smoking/smoking-facts/health-effects/marijuana-and-lung-health
• California Bureau of Cannabis Control Regulations, 16 CCR § 5000 et seq. - https://cannabis.ca.gov/cannabis-laws/rulemaking/
• Tashkin, D.P. (2013). Effects of marijuana smoking on the lung. Annals of the American Thoracic Society, 10(3), 239-247 - https://www.atsjournals.org/
• BDSA Cannabis Market Analytics and Reports - https://bdsa.com/
• Americans for Safe Access Medical Cannabis Research and Policy - https://www.safeaccessnow.org/
• Centers for Disease Control and Prevention Cannabis Health Effects - https://www.cdc.gov/marijuana/