As many as 83 million Chinese might die of lung disease in the next 25 years, a US study says.
Respiratory disease is already a leading cause of death in China, but this latest study suggests a startling rise.
The Harvard School of Public Health research looked at a 30-year period, spanning the last five and the next 25.
In the 30-year period, it calculates, about 83 million Chinese people will die prematurely of lung disease.
The study focused on the devastating impact of smoking and the widespread practice of burning wood or coal at home for cooking and heating.
Prof Majid Ezzati, the study's senior author, says dramatic intervention now by China's government could save many millions of lives.
"If China manages to control tobacco through taxation, through health education, through advertising bans, and if it manages to get clean fuel to the 70% of its population who need cleaner fuels, or ways of burning their current fuels more cleanly, they have a lot of health gains to make."
At the moment, one in three cigarettes lit in the world is smoked in China.
About half of Chinese men smoke, and there is concern the next trend will be an increase in smoking amongst women too.
That has not been factored into the study, and could boost the number of deaths still further.
A previous report had said smoking could eventually kill a third of all young Chinese men if nothing is done to get them to drop the habit.
Two landmark studies involving 1.25m Chinese people show that China has the largest number of smoking-related deaths in the world.
Because of a sharp increase in cigarette sales in the last 30 years, around 2,000 people a day are currently dying of smoking in China.
By 2050, the researchers expect this number could rise to 8,000 a day - some three million people a year.
In the West, smoking causes a high number of heart-related deaths, but in China, the majority of deaths are due to respiratory diseases, including tuberculosis.
Interestingly surveys have shown two-thirds of Chinese people think smoking does little or no harm, 60% think it does not cause lung cancer and 96% do not know that it causes heart disease.