Department of Psychology, San Diego State University, San Diego, California, USA.
Graduate School of Public Health, San Diego State University, San Diego, California, USA.
Tob Control. 2018 Nov;27(6):643-649. doi: 10.1136/tobaccocontrol-2017-054052. Epub 2018 Feb 8.
Secondhand smoke (SHS) in US casinos is common, but little is known about the residue of tobacco smoke pollutants left behind in dust and on surfaces, commonly referred to as thirdhand smoke (THS). We examined SHS and THS pollution and exposure before and during a casino smoking ban and after smoking resumed.
A casino was visited nine times over a 15-month period to collect dust, surface and air samples in eight locations. Finger wipe and urine samples were collected from non-smoking confederates before and after a 4-hour casino visit. Samples were analysed for markers of SHS and THS pollution and exposure.
Exceptionally high levels of THS were found in dust and on surfaces. Although the smoking ban led to immediate improvements in air quality, surface nicotine levels were unchanged and remained very high for the first month of the smoking ban. Surface nicotine decreased by 90% after 1 month (P<0.01), but nicotine and tobacco-specific nitrosamines in dust decreased more slowly, declining by 90% only after 3 months (P<0.01). Exposure was significantly reduced after the ban, but the benefits of the ban were reversed after smoking resumed.
Long-term smoking in a casino creates deep THS reservoirs that persist for months after a smoking ban. A complete smoking ban immediately improves air quality and significantly reduces exposure to SHS and THS. However, THS reservoirs contribute to continued low-level exposure to toxicants. To accelerate the effect of smoking bans, remediation efforts should address specific THS reservoirs, which may require intensive cleaning as well as replacement of carpets, furniture and building materials.
美国赌场中的二手烟（SHS）很常见，但人们对尘埃和表面遗留的烟草烟雾污染物（通常称为三手烟，THS）了解甚少。我们在赌场禁烟令实施前后以及重新吸烟后，检测了 SHS 和 THS 污染和暴露情况。
在 15 个月的时间里，我们在赌场的八个位置进行了九次访问，收集尘埃、表面和空气样本。在非吸烟者参加 4 小时赌场访问前后，收集了手指擦拭物和尿液样本。对样本进行了 SHS 和 THS 污染和暴露标志物的分析。
尘埃和表面的 THS 含量极高。尽管禁烟令立即改善了空气质量，但表面尼古丁水平没有变化，在禁烟令实施的第一个月仍然很高。禁烟令实施 1 个月后，表面尼古丁下降了 90%（P<0.01），但尘埃中的尼古丁和烟草特异性亚硝胺下降较慢，仅在 3 个月后下降了 90%（P<0.01）。禁令实施后，暴露量显著减少，但在重新吸烟后，禁令的好处被逆转。
赌场长期吸烟会产生深的 THS 储存库，即使在禁烟令实施后，这些储存库仍会持续数月。完全禁烟令会立即改善空气质量，并显著减少 SHS 和 THS 的暴露。然而，THS 储存库会导致持续的低水平接触有毒物质。为了加速禁烟令的效果，修复工作应针对特定的 THS 储存库，这可能需要进行密集清洁，以及更换地毯、家具和建筑材料。
