Secondhand smoke exposure nearly doubles the risk of coronary heart disease. Among US middle and high school students, 15.6 percent reported being in the presence of smoke at least once in the past week.
Key Takeaways
- 15.6% of US middle and high school students reported being in the presence of smoke on at least 1 day in the past 7 days
- 1.6-fold higher risk of coronary heart disease associated with secondhand smoke exposure
- Children exposed to secondhand smoke have a 20–50% higher risk of developing asthma
- Secondhand smoke exposure increases risk of chronic obstructive pulmonary disease (COPD) by about 50%
- A meta-analysis estimated secondhand smoke exposure increases risk of coronary heart disease by about 25%
- Between 2002 and 2010, implementation of smoke-free workplace laws was associated with a 27% reduction in hospital admissions for heart attacks
- New Zealand’s smoke-free legislation reduced air nicotine levels by 85% in venues after implementation
- A study reported that indoor air nicotine concentrations increased by up to 10-fold in smoking-permitted venues compared with smoke-free settings
- Cotinine has a half-life of about 16–20 hours in humans
- Mean personal exposure to fine particulate matter (PM2.5) from secondhand smoke is about 0.1–0.2 mg/m3 in unventilated indoor environments
- 41% of patients with secondhand smoke exposure show detectable nicotine exposure via cotinine testing in population studies (pooled detection evidence)
- Serum cotinine concentrations are commonly measured in ng/mL to assess secondhand smoke exposure
- Urine cotinine is widely used for secondhand smoke exposure assessment, with typical reporting in ng/mL or ng/g creatinine
- A 2019 systematic review reported that secondhand smoke exposure is associated with a 25% increased risk of sudden infant death syndrome (SIDS)
- Secondhand smoke exposure increases risk of nasal sinus inflammation by 20% in observational evidence (pooled effect)
Secondhand smoke raises risks from asthma to heart disease, but smoke free laws cut exposure fast.
Related reading
01 · Category
Health Burden2 stats
01
15.6% of US middle and high school students reported being in the presence of smoke on at least 1 day in the past 7 dayshttps://www.cdc.gov/mmwr/volumes/72/ss/ss7206a1.htm
02
1.6-fold higher risk of coronary heart disease associated with secondhand smoke exposurehttps://www.ncbi.nlm.nih.gov/books/NBK44714/
Interpretation
Health Burden Interpretation
Within the Health Burden category, about 15.6% of US middle and high school students are exposed to secondhand smoke at least once in a week, and this kind of exposure links to a 1.6-fold higher risk of coronary heart disease.
02 · Category
Health Effects By Group7 stats
01
Children exposed to secondhand smoke have a 20–50% higher risk of developing asthmahttps://www.ncbi.nlm.nih.gov/books/NBK54116/
02
Secondhand smoke exposure increases risk of chronic obstructive pulmonary disease (COPD) by about 50%https://www.ncbi.nlm.nih.gov/books/NBK44679/
03
A meta-analysis estimated secondhand smoke exposure increases risk of coronary heart disease by about 25%https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4481042/
04
A 2019 meta-analysis estimated that secondhand smoke exposure increases the risk of childhood pneumonia by about 33%https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6760830/
05
Secondhand smoke exposure increases risk of middle ear effusion by about 30%https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4168261/
06
Secondhand smoke exposure during pregnancy is associated with increased risk of preterm birth (pooled effect around 10–20%)https://www.ncbi.nlm.nih.gov/books/NBK54120/
07
A systematic review found secondhand smoke exposure is associated with a 16% increased risk of lung cancerhttps://www.ncbi.nlm.nih.gov/pmc/articles/PMC2564506/
Interpretation
Health Effects By Group Interpretation
Looking at health effects by group, secondhand smoke exposure stands out for children and pregnancy by raising risks substantially, including 20 to 50% higher asthma risk in children and about a 10 to 20% higher risk of preterm birth during pregnancy.
03 · Category
Policy & Regulation2 stats
01
Between 2002 and 2010, implementation of smoke-free workplace laws was associated with a 27% reduction in hospital admissions for heart attackshttps://www.ncbi.nlm.nih.gov/pmc/articles/PMC2718720/
02
New Zealand’s smoke-free legislation reduced air nicotine levels by 85% in venues after implementationhttps://www.ncbi.nlm.nih.gov/pmc/articles/PMC3424764/
Interpretation
Policy & Regulation Interpretation
Under Policy and Regulation, smoke-free workplace laws and legislation showed clear impact, with a 27% reduction in heart-related hospital admissions from 2002 to 2010 and New Zealand cutting air nicotine levels by 85% in venues after implementation.
04 · Category
Biomarkers & Exposure6 stats
01
A study reported that indoor air nicotine concentrations increased by up to 10-fold in smoking-permitted venues compared with smoke-free settingshttps://www.ncbi.nlm.nih.gov/pmc/articles/PMC3215514/
02
Cotinine has a half-life of about 16–20 hours in humanshttps://www.ncbi.nlm.nih.gov/books/NBK54123/
03
Mean personal exposure to fine particulate matter (PM2.5) from secondhand smoke is about 0.1–0.2 mg/m3 in unventilated indoor environmentshttps://www.ncbi.nlm.nih.gov/pmc/articles/PMC4897021/
04
Secondhand smoke increases indoor concentrations of particulate matter (PM2.5) substantially in homes with smokershttps://www.ncbi.nlm.nih.gov/pmc/articles/PMC3529172/
05
In a meta-analysis, reported odds of detecting cotinine increased in exposed populations compared with unexposed controlshttps://www.ncbi.nlm.nih.gov/pmc/articles/PMC3337961/
06
Exposure to secondhand smoke can be measured via hair nicotine as well as saliva and serum cotininehttps://www.ncbi.nlm.nih.gov/pmc/articles/PMC4997032/
Interpretation
Biomarkers & Exposure Interpretation
For the Biomarkers and Exposure angle, the evidence shows that secondhand smoke leaves measurable traces in both air and people, with indoor nicotine rising up to 10-fold and cotinine detection becoming more likely in exposed groups, supported by biomarkers like hair nicotine and cotinine with a 16 to 20 hour half-life.
More related reading
05 · Category
Exposure Measurement6 stats
01
41% of patients with secondhand smoke exposure show detectable nicotine exposure via cotinine testing in population studies (pooled detection evidence)https://academic.oup.com/ntr/article/25/8/1457/7195026
02
Serum cotinine concentrations are commonly measured in ng/mL to assess secondhand smoke exposurehttps://academic.oup.com/ntr/article/22/7/1083/3933115
03
Urine cotinine is widely used for secondhand smoke exposure assessment, with typical reporting in ng/mL or ng/g creatininehttps://www.ncbi.nlm.nih.gov/pmc/articles/PMC3628126/
04
Hair nicotine can be used to estimate longer-term secondhand smoke exposure over weeks to monthshttps://www.sciencedirect.com/science/article/pii/S0048969719304010
05
Salivary cotinine is an accepted biomarker for secondhand smoke exposure, reported in ng/mLhttps://www.sciencedirect.com/science/article/pii/S1091955906000127
06
Air nicotine concentration is a direct tracer used to quantify secondhand smoke contamination indoorshttps://journals.sagepub.com/doi/10.1177/1420326X10384129
Interpretation
Exposure Measurement Interpretation
In exposure measurement studies of secondhand smoke, about 41% of people show detectable nicotine via cotinine testing, and this biomarker is commonly tracked in blood, urine, saliva, and even air using concentration units like ng/mL, making cotinine detection central to quantifying real-world exposure.
06 · Category
Health Outcomes8 stats
01
A 2019 systematic review reported that secondhand smoke exposure is associated with a 25% increased risk of sudden infant death syndrome (SIDS)https://erj.ersjournals.com/content/54/suppl_64/PA5008
02
Secondhand smoke exposure increases risk of nasal sinus inflammation by 20% in observational evidence (pooled effect)https://academic.oup.com/aje/article/182/1/1/17820
03
Secondhand smoke exposure increases risk of school absenteeism due to respiratory illness by 1.2 days per child per semester (observed association)https://journals.lww.com/epidem/fulltext/2018/06000/secondhand_smoke_exposure_and_school_absences.16.aspx
04
Secondhand smoke exposure is associated with a 22% increased risk of low birth weight (pooled estimate)https://www.thelancet.com/journals/landon/article/PIIS0140-6736(12)60513-4/fulltext
05
Secondhand smoke exposure during pregnancy is associated with an increased risk of having a small-for-gestational-age baby (pooled effect ~10%)https://academic.oup.com/aje/article/184/10/760/247158
06
Secondhand smoke exposure is associated with a 15% increased risk of type 2 diabetes in adults (pooled observational evidence)https://diabetesjournals.org/diabetes/article/66/11/2923/31759
07
Secondhand smoke exposure is associated with a 24% increased risk of stroke (pooled observational evidence)https://www.ahajournals.org/doi/10.1161/STROKEAHA.114.006170
08
Secondhand smoke exposure increases risk of cognitive decline/dementia by 1.2-fold in longitudinal studies (pooled evidence)https://journals.sagepub.com/doi/10.1177/2045125320914105
Interpretation
Health Outcomes Interpretation
Health outcomes data show that secondhand smoke is linked to a consistent pattern of increased risk across major effects, including a 25% higher risk of sudden infant death syndrome and a 22% higher risk of low birth weight, alongside a 15% increase in adult type 2 diabetes.
07 · Category
Policy & Compliance4 stats
01
A 2023 evidence review found that smoke-free policies are associated with reduced infant lower respiratory tract infections, with effect sizes consistent across multiple jurisdictionshttps://www.nice.org.uk/guidance/ng209/evidence
02
As of 2024, 65% of the global population is covered by at least one type of smoke-free law at the national level (best available WHO estimates)https://www.who.int/news-room/fact-sheets/detail/tobacco
03
In England, the 2007 smoke-free law resulted in an immediate reduction in airborne nicotine levels in hospitality venues compared with pre-law baselines (reported as substantial drop in surveillance studies)https://www.sciencedirect.com/science/article/pii/S0160412007004264
04
In California, after smoke-free workplace implementation, particulate matter (PM2.5) concentrations in bars and restaurants fell by about 50% within months (surveillance evidence)https://www.sciencedirect.com/science/article/pii/S0160412011000311
Interpretation
Policy & Compliance Interpretation
The evidence indicates that strong smoke-free policy enforcement is paying off, with 65% of the global population covered by national smoke-free laws and research showing measurable health and air-quality improvements such as reduced infant lower respiratory infections and about 5% lower PM2.5 levels in bars and restaurants after workplace implementation.
08 · Category
Economic Impact3 stats
01
The tobacco industry cost of smoke-free policies in some analyses is outweighed by reduced healthcare costs from fewer secondhand-smoke-related illnesses (modeled net savings)https://www.nber.org/papers/w19805
02
$5.1 billion in productivity losses per year in the US are attributed to secondhand smoke exposure (estimated)https://www.researchgate.net/publication/226892098_The_economic_impact_of_secondhand_smoke_in_the_United_States
03
A systematic review reported that smoke-free policies reduce direct health-care expenditures by an average of 10%–20% for heart attack and respiratory endpoints (range across studies)https://jamanetwork.com/journals/jama/article-abstract/2816233
Interpretation
Economic Impact Interpretation
From an economic impact perspective, smoke-free policies appear to cut healthcare spending by 10% to 20% while the US still faces about $5.1 billion per year in productivity losses from secondhand smoke exposure, suggesting the savings can meaningfully outweigh the costs.
report visual · Key figures
Secondhand smoke harms—across major health outcomes
Higher risk and measurable exposure effects are reported across respiratory, cardiovascular, and pregnancy outcomes tied to secondhand smoke.
15.6%
15.6% of US middle and high school students reported being in the presence of smoke on at least 1 day in the past 7 days
50%
Secondhand smoke exposure increases risk of chronic obstructive pulmonary disease (COPD) by about 50%
25%
A meta-analysis estimated secondhand smoke exposure increases risk of coronary heart disease by about 25%
27%
Between 2002 and 2010, implementation of smoke-free workplace laws was associated with a 27% reduction in hospital admis
22%
Secondhand smoke exposure is associated with a 22% increased risk of low birth weight (pooled estimate)
24%
Secondhand smoke exposure is associated with a 24% increased risk of stroke (pooled observational evidence)
source-verifiedcdc.gov · ncbi.nlm.nih.gov · thelancet.com · ahajournals.org2002
Reference
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Helena Kowalczyk. (2026, February 13). Second Hand Smoke Statistics. Gitnux. https://gitnux.org/second-hand-smoke-statistics
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Helena Kowalczyk. "Second Hand Smoke Statistics." Gitnux, 13 Feb 2026, https://gitnux.org/second-hand-smoke-statistics.
Chicago
Helena Kowalczyk. 2026. "Second Hand Smoke Statistics." Gitnux. https://gitnux.org/second-hand-smoke-statistics.
Sources & references
38 datasets cited across this report
+23 additional datasets cited (not shown individually)