More than one in four people who work indoors are being exposed to second-hand smoke at work, according to new research.

The abstract, which was presented at the 2017 European Respiratory Society (ERS) International Congress in Milan, looked at all 28 countries currently in the European Union (EU), the majority of which have introduced smoke-free legislation to protect workers from second-hand smoke.

Although the study found a reduction in the number of people exposed to second-hand smoke in restaurants and bars, it also revealed that the number of people exposed in indoor workplaces such as offices, shops, and factories, has increased from 2009.

Dr Filippos Filippidis, lead author from Imperial’s School of Public Health, said: “This research is an essential way for us to monitor the progress that EU countries are making in upholding smoke-free laws.

He added: “Our results suggest that progress is being made to protect people visiting bars and restaurants, but it is worrying to see that the number of workers in offices, shops and factories who are being exposed to second-hand smoke is actually increasing. “Some countries, such as Sweden, the UK and Ireland, are doing well and setting an example for what can be achieved. Others, such as Greece and Cyprus, are falling behind.”

The research compared two surveys five years apart, spanning more than 55,000 people across the EU. Around half were surveyed in 2009 and the other half in 2014.

During the time between surveys several countries, including Bulgaria, Spain, Belgium and Hungary, introduced stricter legislation to ban smoking in public buildings and indoor work places to protect workers.

These new laws, and better enforcement of existing regulations, were reflected in the results of the surveys.

In 2014, one in four said they had been exposed to second-hand smoke when they visited a bar in the last year, compared to almost one in two in 2009 (25.1 per cent compared to 45.1 per cent).

For restaurants, it was one in nine in 2014, compared to around one in three in 2009 (11.8 per cent compared to 30.2 per cent).

However, of those people who work indoors, 27.5 per cent said they had been exposed to second-hand smoke at work in 2014. This has risen from 23.8 per cent in 2009.

The authors say it can be harder to enforce smoke-free legislation in workplaces because it relies on individuals making complaints. Although there are laws in place, they are not implemented to the same extent in all countries. For example, rules might not be enforced in some countries, with complaints not being dealt with appropriately.

Even after a complaint is made, there could be a lack of mechanisms, such as fines, to enforce the rules.

The effects of exposure to second-hand smoke are well established by medical research. It is known to increase the risks of stroke, coronary heart disease and lung cancer, and is responsible for more than 600,000 deaths per year around the world.

Dr Filippidis continues: “Our results suggest there is still a lot more work to be done to protect people in some parts of Europe. The first step is for all countries to pass comprehensive smoke-free legislation, as there are still places where laws are weak. Some countries clearly have very effective mechanisms for enforcing existing legislation, and the rest just need to follow their lead.”