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The effect of São Paulo's smoke-free legislation on carbon monoxide concentration in hospitality venues and their workers
  1. Jaqueline S Issa1,
  2. Tania M O Abe1,
  3. Alexandre C Pereira1,
  4. Maria Cristina Megid2,
  5. Cristina E Shimabukuro2,
  6. Luis Sergio O Valentin2,
  7. Marizete M da C Ferreira2,
  8. Moacyr R C Nobre1,
  9. Ines Lancarotte1,
  10. Antonio Carlos Pereira Barretto1
  1. 1Heart Institute, Smoking Cessation Program department, Medicine Faculty, University of São Paulo, SP, Brazil
  2. 2São Paulo State Center of Surveillance, São Paulo, Brazil
  1. Correspondence to Dr Jaqueline Scholz Issa, Heart Institute, Medicine Faculty, University of São Paulo, Rua Dr Eneas de Carvalho Aguiar 44, 1 andar Bloco2, CEP, São Paulo 05403- 000, São Paulo, Brazil; jaqueline{at}


Background Studies have shown that there is no safe level of secondhand smoke (SHS) exposure and there is a close link between SHS and the risk of coronary heart disease and stroke. Carbon monoxide (CO) is one of the most important components present in SHS.

Objective To evaluate the impact of the smoking ban law in the city of Sao Paulo, Brazil, on the CO concentration in restaurants, bars, night clubs and similar venues and in their workers.

Methods In the present study we measured CO concentration in 585 hospitality venues. CO concentration was measured in different environments (indoor, semi-open and open areas) from visited venues, as well as, in the exhaled air from approximately 627 workers of such venues. Measurements were performed twice, before and 12 weeks after the law implementation. In addition, the quality of the air in the city during the same period of our study was verified.

Results The CO concentration pre-ban and pot-ban in hospitality venues was indoor area 4.57 (3.70) ppm vs 1.35 (1.66) ppm (p<0.0001); semi-open 3.79 (2.49) ppm vs 1.16 (1.14) ppm (p<0.0001); open area 3.31(2.2) ppm vs 1.31 (1.39) ppm (p<0.0001); smoking employees 15.78 (9.76) ppm vs 11.50 (7.53) ppm (p<0.0001) and non-smoking employees 6.88 (5.32) ppm vs 3.50 (2.21) ppm (p<0.0001). The average CO concentration measured in the city was lower than 1 ppm during both pre-ban and post-ban periods.

Conclusion São Paulo's smoking-free legislation reduced significantly the CO concentration in hospitality venues and in their workers, whether they smoke or not.

  • Carbon monoxide concentration
  • smoke-free legislation
  • secondhand smoke
  • environmental tobacco smoke
  • public policy

This is an open-access article distributed under the terms of the Creative Commons Attribution Non-commercial License, which permits use, distribution, and reproduction in any medium, provided the original work is properly cited, the use is non commercial and is otherwise in compliance with the license. See: and

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  • Funding This study was funded by Fundação Zerbini and São Paulo State Department of Health.

  • Competing interests JI has consulted for Pfizer and has been principal investigator for clinical trials of smoking cessation medications funded by Pfizer and other clinical trials funded by Lilly. The other authors report no conflicts.

  • Patient consent Obtained.

  • Ethics approval This study was conducted with the approval of the CAPPESQ ethics committee for research project evaluation of the Hospital das Clinicas, School of Medicine, University of São Paulo.

  • Provenance and peer review Not commissioned; externally peer reviewed.