Researchers from the University of Washington looked at how exposure to four main pollutants affected lung health in 7,071 adults aged 45 to 84 living in six US city areas.
Following up on the participants for an average of 10 years, they measured levels of fine particulate matter, nitrogen oxide, black carbon and ozone outside their homes and carried out CT scans to track the development of emphysema and lung decline.
The study found that long-term exposure to all of the pollutants was linked to an increased percentage of emphysema, with ground level ozone in particular leading to a decline in lung function.
Ground-level ozone is produced when UV light reacts with pollutants from fossil fuels, and the process is accelerated by heatwaves.
While most levels of air pollution are in decline due to successful efforts to reduce them, ozone has been increasing.
In areas with increased levels of ozone, the research found an increase in emphysema roughly the equivalent of smoking a pack of cigarettes a day for 29 years.
Senior co-author Dr Joel Kaufman, from the University of Washington, said: "We were surprised to see how strong air pollution's impact was on the progression of emphysema on lung scans, in the same league as the effects of cigarette smoking, which is by far the best-known cause of emphysema."
He added: "We really need to understand what's causing chronic lung disease, and it appears that air pollution exposures that are common and hard to avoid might be a major contributor."