Secondhand tobacco smoke exposure in open and semi-open settings: A systematic review

Xisca Sureda, Esteve Fernández, María J. López, Manel Nebot

Research output: Contribution to journalArticlepeer-review


Background: Some countries have recently extended smoke-free policies to particular outdoor settings; however, there is controversy regarding whether this is scientifically and ethically justifiable. Objectives: The objective of the present study was to review research on secondhand smoke (SHS) exposure in outdoor settings. Data sources: We conducted different searches in PubMed for the period prior to September 2012. We checked the references of the identified papers, and conducted a similar search in Google Scholar. Study selection: Our search terms included combinations of "secondhand smoke," "environmental tobacco smoke," "passive smoking" OR "tobacco smoke pollution" AND "outdoors" AND "PM" (particulate matter), "PM2.5" (PM with diameter ≤ 2.5 μm), "respirable suspended particles," "particulate matter," "nicotine," "CO" (carbon monoxide), "cotinine," "marker," "biomarker" OR "airborne marker." In total, 18 articles and reports met the inclusion criteria. Results: Almost all studies used PM2.5 concentration as an SHS marker. Mean PM2.5 concentrations reported for outdoor smoking areas when smokers were present ranged from 8.32 to 124 μg/m3 at hospitality venues, and 4.60 to 17.80 μg/m3 at other locations. Mean PM2.5 concentrations in smoke-free indoor settings near outdoor smoking areas ranged from 4 to 120.51 μg/m3. SHS levels increased when smokers were present, and outdoor and indoor SHS levels were related. Most studies reported a positive association between SHS measures and smoker density, enclosure of outdoor locations, wind conditions, and proximity to smokers. Conclusions: The available evidence indicates high SHS levels at some outdoor smoking areas and at adjacent smoke-free indoor areas. Further research and standardization of methodology is needed to determine whether smoke-free legislation should be extended to outdoor settings.

Original languageEnglish (US)
Pages (from-to)766-773
Number of pages8
JournalEnvironmental Health Perspectives
Issue number7
StatePublished - Jul 2013
Externally publishedYes


  • Exposure markers
  • Outdoor tobacco smoke
  • Particulate matter
  • Passive smoking
  • Secondhand smoke
  • Smoking ban
  • Tobacco smoke pollution

ASJC Scopus subject areas

  • Health, Toxicology and Mutagenesis
  • Public Health, Environmental and Occupational Health


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