This study quantified the secondhand smoke (SHS) concentration in a sample of public places in Vietnam to determine changes in SHS levels 5 years after a public smoking ban was implemented.
Two monitoring campaigns, one in 2013 (before the tobacco control law was implemented) and another in 2018 (5 years after the implementation of the law) were conducted in around 30 restaurants, cafeterias and coffee shops in major cities of Vietnam. Concentrations of PM2.5, as an indicator of SHS, were measured by portable particulate matter monitors (TSI SidePak AM510 and Air Visual Pro).
The geometric mean PM2.5 concentration of all monitored venues was 87.7 µg/m3 (83.7–91.9) in the first campaign and 55.2 µg/m3 (53.7–56.7) in the second campaign. Pairwise comparison showed the PM2.5 concentrations in the smoking observed area was triple and double those in the non-smoking area and the outdoor environment. After adjusting for sampling locations and times, the SHS concentration 5 years after the implementation of the tobacco control law reduced roughly 45%.
The study results indicate an improvement in air quality in public places in Vietnam via both the reduction in PM2.5 levels and the number of people observed smoking. However, greater enforcement of the free-smoke legislation is needed to eliminate SHS in public places in Vietnam.