PETER Lavac, a Sydney lawyer, fitness fanatic and champion surf skier, thought something was wrong when he was not breathing as freely.

Knowing smoke was getting into his air from a flat below where a chain-smoking couple lived, he tried to get them to stop. Unsuccessful, he then approached the body corporate, strata title management and the tenancy tribunal, but to no avail.

Fitness fanatic Peter Lavac. Credit:Marco Del Grande

He consulted a respiratory specialist, Professor Matthew Peters, who told him to monitor his condition. ''From this data and my symptoms, Professor Peters concluded on the balance of probabilities that my symptoms and decrease in lung function were caused by the second-hand cigarette smoke,'' he said.

Professor Peters told Mr Lavac, 65, and his wife to reduce their exposure. After living in their flat for 18 months in 2005-06, they moved. In March, 2008, Mr Lavac felt unwell. A CT scan detected a shadow at the top of his right lung, and a biopsy confirmed cancer. ''I had been training for almost a year for a long-distance open ocean surf-ski race in Hawaii,'' he said. ''My whole life was turned upside down. One week I was trying to figure out how much water I would need to get me from Molokai to Oahu. The following week I was on the operating table.''

Mr Lavac, who had never smoked, lost a third of his right lung. His surgeon and Professor Peters told him that, on the balance of probabilities, the lesion had been caused by passive smoking. He has had no recurrence of the symptoms and is back in training, though his breathing capacity will always be more limited. He is planning legal action against the people he claims caused his disease: the smokers, body corporate and the strata management company.

Mr Lavac said there were many situations, such as in multi-unit buildings, retirement villages and nursing homes with similar dangers of smoke intrusion through windows, vents, cavities and other spaces.

Professor Peters, chairman of Action on Smoking and Health, said there was no lower limit for exposure to smoking. ''If you can smell smoke, it is hurting you,'' he said.