Introduction
Substantial evidence indicates that smoking bans reduce the adverse effects of exposure to tobacco smoke. As a result of this evidence, smoking bans in public places have been implemented in many countries. Furthermore, partial smoking bans in indoor public places and workplaces are becoming a common occurrence [1, 2] . However, the issue of implementing complete smoking bans in all indoor public places has been debated in several countries. This disagreement depends on several factors including the societal view of smoking, compliance with existing smoke-free legislation, and other sociopolitical considerations.
Introduction
In 1995, the Republic of Korea passed a law that banned smoking in public places. Excluded from this ban were restaurants, recreational facilities, and entertainment venues, although some were subject to a partial smoking ban (i.e., facilities had to have both smoking and non-smoking areas that were physically separated) [3] . For example, one type of recreational facility, personal computer (PC) rooms, underwent a partial smoking ban. However, it is well-known that individuals within PC rooms will still be exposed to secondhand smoke (SHS), as there is air flow between the separated smoking and non-smoking areas. In Korea, there are 15,817 PC rooms, all of which provide a facility for individuals to play computer games. Survey data indicated that 45.2% of the population spends their leisure time in PC rooms. This percentage is higher than that at cinemas (33.5%), cafés (31.2%), or bars (26.2%). Furthermore, approximately 63.8% of adolescents regularly spend their leisure time in PC rooms [4] .
Introduction
PC rooms became a top priority for the 2011 Complete Smoking Ban placed on public indoor facilities. However, the implementation of this ban on PC rooms was delayed until 2013. This ban was delayed because owners of PC rooms and smokers' groups argued that the ban was not necessary, citing smokers' rights and the lack of evidence supporting the effectiveness of a partial ban in protecting individuals from SHS exposure.
Introduction
In this study, we investigated the levels of SHS exposure in smoking and non-smoking areas of PC rooms prior to 2013, to determine whether a complete smoking ban in PC rooms in necessary. Thus, the results from this study will provide data that will impact the debate on a complete smoking ban in PC rooms.
Materials and Methods
From June to September 2012, particulate matter (PM2.5) and air nicotine concentrations (ANC) were measured in the smoking and non-smoking areas of a random sample of 28 PC rooms. PC rooms were located in Goyang City, a residential satellite city of the capital Seoul. For each PC room, field researchers completed an observational questionnaire on the ventilation, air conditioning, and heating systems as well as the facility's policies on smoking (e.g., restricted or permitted smoking, tobacco sales permitted, tobacco advertising allowed). In addition, field researches looked for evidence of smoking. Monitoring equipment was concealed and measurements occurred in a blind manner (i.e., owners, employees, patrons, etc. had no knowledge of this study).
Materials and Methods
PM2.5 concentrations were measured using a MetOne Acrocet 531 Aerosol Particulate Profiler (Grants Pass, OR) for a minimum of 30 minutes in the smoking and non-smoking areas of each PC room. Researchers waited 10 minutes between measurements taken in each PC room. All PM2.5 concentrations measured were multiplied by 8.33 to adjust for the underestimation associated with monitoring the gravimetric PM2.5 concentration using that machine [5] .
Materials and Methods
ANC was measured using passive samplers (a 37-mm polystyrene sampling cassette holding a Teflon-coated glass fiber filter treated with 4% sodium bisulfate and 5% ethanol). Passive samplers were hung 1-2 m from the floor and at least 1 m from open windows and ventilation systems in order to avoid air circulation (i.e., "dead spots"). The sampling rate was 24 mL/min and the calculated limit of detection was 0.05 µg/m 3 over a 7-day sampling period. Exposed filters were extracted and nicotine was analyzed using a gas chromatograph equipped with a nitrogen phosphorous detector (7820A, Agilent Technologies, Santa Clara, CA) [6] , with 10% of the samples duplicated. Final ANC values were calculated by subtracting out background levels measured using blank samples.
Materials and Methods
Geometric means (GM) and geometric standard deviations were calculated and statistical analyses were performed using SAS ver. 9.3 (SAS Institute Inc., Cary, NC). This study was approved by the Institutional Review Board of National Cancer Center of Korea.
Results
All PC rooms had centralized air conditioning and heating systems that were functioning during the rooms' hours of operation. According to the partial smoking ban implemented at the time this study was performed, all PC rooms were required to obey the following regulations: install a ventilation system for extracting smoke, prohibit the sale of tobacco, ban promotion and advertisement of tobacco, and had to post "no smoking" signs in non-smoking areas. In all PC rooms, we observed the implementation of these regulations. Despite these rules being followed, evidence of smoking was identified in both smoking and non-smoking areas in all PC rooms.
Results
The GM of PM2. 
Discussion
On May 16, 2005 , Korea ratified the Framework Convention on Tobacco Control, which accelerated implementation of laws protecting individuals from the negative side effects of SHS and reduced the prevalence of smoking (48.1% males and 6.1% females) [7] . In June 2011, the amended National Health Promotion Law expanded the complete smoking ban to include recreational facilities. Recreational facilities, such as PC rooms, are a location in which individuals spend the majority of their leisure time [3, 8] . The partial smoking ban implemented prior to the Rewritten National Health Promotion Law of 2011 required facilities to construct a wall or air curtain between smoking and non-smoking areas as well as install ventilation systems to combat tobacco smoke [9] . However, the partial smoking ban did not prevent the flow of tobacco smoke between areas.
Discussion
Opponents of the 2011 law, including the owners of PC rooms, organized to repeal the complete smoking ban and argued that the law was unconstitutional. This action was ultimately unsuccessful, but did delay implementation until June 8, 2013 . In this study, we measured the levels of tobacco smoke in PC rooms prior to June 8, 2013 , during the period of delay of the complete smoking ban. Our results indicated that the PM2.5 concentrations and ANC in the smoking and non-smoking areas of PC rooms were similar. Thus, the results of this study support implementation of a complete smoking ban.
Discussion
We observed ANCs that were greater than 10-fold higher that those in a previous report of ANCs in an entertainment venue in Seoul that permits smoking without restriction [10] . The PM2.5 concentration observed in non-smoking areas of PC rooms was very high. The PM2.5 concentration in smoking and non-smoking areas combined was similar to those previously reported in cafés, bars/clubs, entertainment venues, and smoking rooms worldwide [11] [12] [13] [14] [15] . Our results support previous data in that we observed that SHS exposure in PC rooms was very high and that the partial smoking ban is unlikely to protect individuals in non-smoking areas from SHS exposure [11, 13, 15, 16] . By means of an official government report and an article in a major daily newspaper [17] , we announced our findings to the public and informed Korean citizens that the most effective protection from SHS exposure in non-smoking areas is implementation of a complete smoking ban in PC rooms. Although our study sampled only a small number of PC rooms in one city, it supports the necessity of a complete smoking ban.
Discussion
The complete ban on smoking in PC rooms has been in force since January 1, 2014 [3, 8] . Furthermore, it stimulated governmental efforts to expand smoke-free legislation in Korea.
Conclusion
We conclude that our research supports the complete smoking ban and may provide the necessary scientific evidence for other countries that have not yet implemented comprehensive smoke-free policies. Nine PC rooms that showed values lower than the limit of detection were not included in the calculation.

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