Smokers beware. Fresh data from cities with high levels of air pollution indicate that air quality inside venues where people smoke is worse than outdoors.

According to this international study conducted and released early this week, which also looked at Delhi, the six cities surveyed with dangerous levels of air pollution indicates that air quality inside venues that allow smoking is even worse than outdoors.

The study, published in the journal Nicotine & Tobacco Research, was co-authored by tobacco control experts at the International Union Against Tuberculosis and Lung Disease [The Union] and the University of Aberdeen, Scotland.

Readings were taken in cafes, bars and restaurants to reveal levels of compliance with smoke-free rules in Delhi (India), Islamabad (Pakistan), Denpasar (Indonesia), N’Djamena (Chad), Dhaka (Bangladesh) and Mexico City (Mexico).

During the same time period, air quality was also measured outside. In all cities – with the exception of Mexico City – the average outdoor air pollution exceeded safe levels specified by the World Health Organization’s [WHO] 24-Hour Air Quality Guidance for PM2.5 (25 micrograms/m3).

And across all cities, where smoking was observed in venues, the indoor air quality was on average substantially poorer than the outdoor air.

Author Dr. Angela Jackson-Morris, Senior Grants Officer at The Union’s Department of Tobacco Control said: “We often hear about how bad outdoor air quality is in the cities we studied, but there is little attention paid to how pollutant levels are frequently even worse indoors when smoking takes place.”

The study notes that these six countries already have legislation to prohibit smoking in bars, cafes and restaurants – it is now time to make sure it is implemented to protect people from the cancers and cardiovascular disease caused by breathing in second-hand tobacco smoke.

“The data clearly shows that if smoke-free laws are poorly enforced then people remain exposed to high levels of second-hand smoke with the well-recognised health risks that involves,” noted the study.

For the study, researchers used a low-cost monitoring device to gather objective air quality data by measuring fine particulate matter (PM2.5) in around 100 hospitality venues in each of the six cities. National smoke-free legislation – banning smoking in indoor public places – is in force in each of the locations.

Data shows that if smoke-free laws are poorly enforced then people are exposed to high levels of second-hand smoke