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As for the measures to isolate smokers from non-smokers in the same air environment, it is impossible to eliminate the second-hand smoke exposure of non-smokers simply by isolating smokers from non-smokers without providing any isolation barrier from floor to ceiling. 56, 57, 58, 59, 60 Non-smokers' exposure to second-hand smoke in this space largely depends on factors such as airflow pattern, dilution volume, distance between smokers and non-smokers, and smoking volume. Almost without exception, heating, ventilation and air conditioning systems will return air from smoke pollution to non-smoking areas. A study on the environmental nicotine level in Latin America (an indicator of secondhand smoke exposure) even found that in some environments, the nicotine level in non-smoking areas is higher than that in neighboring smoking areas. 4 1 in addition, the research on the staff in non-smoking areas also shows that the exposure level of these staff to second-hand smoke is equivalent to that of the staff in smoking areas. 6 1、62

Set up a "special smoking area" to strengthen ventilation and filtration. Neither ventilation nor air filtration, whether used alone or at the same time, can reduce the exposure of tobacco smoke in indoor environment to a qualified level-this method can't even deodorize, let alone protect health. 63, 64 Although it is true that increasing ventilation rate can reduce the concentration of pollutants including tobacco smoke, it is necessary to increase ventilation rate to 65,438+000 times of conventional ventilation rate even for the purpose of deodorizing, 63 and odor is not an indicator to reflect the level of toxic substances in the air, because even if there is no obvious smell of tobacco smoke, the level of these toxic substances may still be high. Eliminating toxic substances requires higher ventilation rate to protect health, but such ventilation rate is neither realistic nor economical in practice. To achieve the purpose of removing toxic substances from secondhand smoke in the air, the number of air changes will be too high to operate, making people feel uncomfortable and economically unbearable. 65

Similarly, neither central air purification equipment nor local purification equipment can reduce the toxic substances of indoor second-hand smoke to a safe level. In addition, the working efficiency of these devices will gradually decrease over time, because they need high-level and expensive maintenance, and sometimes these devices may even become indoor pollution sources themselves. The "one-way" system advocated by the tobacco industry and its allies does not have the problem of circulating air, but for the same reason, the operating cost of this equipment is very high, because indoor air must be heated or cooled continuously. In addition, under any circumstances, the system itself cannot reduce tobacco smoke to a safe level. 66、67

Despite decades of pressure from the tobacco industry, 68 American Society of Heating, Refrigeration and Air Conditioning Engineers (ASHRAE), the main organization of ventilation professional standards in the United States, no longer provides ventilation standards in the case of smoking. The conclusion of the association's opinion on environmental tobacco smoke F in 2005 is: "At present, the only effective means to solve the health problems related to indoor pollution exposure is to ban smoking." At the same time, the submission pointed out: "According to the purpose of safeguarding public interests, the American Society of Heating, Refrigeration and Air Conditioning Engineers advocates that eliminating indoor smoking is the best means to reduce environmental tobacco smoke exposure."

At present, the International Organization for Standards is drafting the recommended standard on ventilation and tobacco smoke (ISO 168 14), which is drafted by the ISO/TC205 Technical Committee responsible for building environment design. However, policy makers must clearly realize that ISO organization standards were greatly influenced by the tobacco industry in the past. In addition, the current ISO 168 14 standard admits that "there is no feasible ventilation and ventilation combination to provide a reasonable and safe environment under the condition of allowing smoking", but at the same time, it also creates an illusion that ventilation and ventilation measures can avoid air circulation in smoking areas or from smoking areas to non-smoking areas. The opinion of American Society of Heating, Refrigeration and Air Conditioning Engineers in 2005 reflects the best scientific evidence about ventilation and secondhand smoke, but this version of ISO 168 14 is not the case.

A ventilation measure promoted by the tobacco industry and adopted by some places (mainly bars and restaurants) is to separate smoking areas from non-smoking areas with physical barriers and install independent ventilation systems. These so-called "special smoking rooms" (DSRS) exhaust the exhaust gas to the outside, and use separate air intake to form a negative pressure zone relative to the surrounding environment. The test results of the protective effect of the design show that according to the existing literature, the special smoking room can reduce but not completely eliminate the exposure of second-hand smoke; In addition, the special smoking room can not solve the problem of second-hand smoke exposure of non-smokers in the adjacent environment. 7 1 72 cannot provide protection for workers working in smoking areas, and may aggravate the exposure of smokers to second-hand smoke, thus increasing health risks. For example, the door of the smoking room acts as a water pump. Whenever someone enters or leaves the room, it will take the smoke out of the room.

In addition, the construction of special smoking room is troublesome and the operating cost is high (block diagram 1). Due to these problems in the implementation process, some areas that have allowed the establishment of special smoking rooms have revised their laws and regulations and completely canceled this facility. The trend of establishing special smoking rooms in the service industry will bring trouble to the health prospects of staff, because it will expose the staff working in it to extremely high second-hand smoke environment. In addition, even worse, the mandatory establishment of special smoking rooms will encourage or require businesses to invest a lot of money to buy or use ineffective ventilation systems, which will bring trouble to the future "100% smoke-free legislation". Because by then, many organizations think that these facilities have invested a lot of cost. G