Secondhand smoke exposures in indoor public places in seven Asian countries

Exposure to secondhand smoke (SHS) is a major threat to public health. Asian countries having the highest smoking prevalence are seriously affected by SHS. The objective of the study was to measure SHS levels in hospitality venues in seven Asian countries and to compare the SHS exposure to the levels in Western countries. The study was carried out in four types of related hospitality venues (restaurant, café, bar/club and entertainment) in China, India, Japan, Korea, Malaysia, Pakistan and Sri Lanka. Real-time measurement of particulate matter of <2.5 μm aerodynamic diameter (PM2.5) was made during business hour using a handheld laser operated monitor. A total of 168 venues were measured in seven countries. The average indoor PM2.5 level was 137 μg/m3, ranging from 46 μg/m3 in Malaysia to 207 μg/m3 in India. Bar/club had the highest PM2.5 level of 191 μg/m3 and restaurants had the lowest PM2.5 level of 92 μg/m3. The average indoor PM2.5 level in smoking venues was 156 μg/m3, which was 3.6 times higher than non-smoking venues (43 μg/m3). Indoor PM2.5 levels were significantly associated with country, type of venue, smoking density and air exchange rate (p < 0.05). In the seven Asian countries, PM2.5 levels were high due to SHS in public places. The current levels are comparable to the levels in Western countries before the adoption of smoke-free policy. Since Asian country has high prevalence of SHS in public places, there is an urgent need for comprehensive smoke-free regulation in Asian countries.