Exposure to air pollution over a long-term period raises your risk of developing emphysema – a debilitating respiratory disease traditionally linked to smoking. What's more, human-driven climate change could be making things worse.
While many airborne pollutants are on the decline thanks to legislation like the now-threatened Clean Power Plan, ozone levels are continuing to increase. And levels just 3 parts per billion (ppb) higher than a different location over 10 years are enough to increase your risk of emphysema by as much as smoking a pack of cigarettes every day for 29 years, according to a new study.
Researchers writing in The Journal of the American Medical Association (JAMA) tracked air pollutants across six urban areas – Chicago, Winston-Salem, (North Carolina), Baltimore, Los Angeles, St. Paul, Minnesota, and New York – and lung function in more than 7,000 people recruited from the Multi-Ethnic Study of Atherosclerosis (MESA) Air and Lung studies between 2000 and 2018.
Longitudinal increases in percent emphysema measured via more than 15,000 CT scans taken over the 18-year period revealed a strong positive correlation between all forms of air pollution and diagnoses of the disease. Average levels of the pollutant varied across the areas and time period studied but were between 10 and 25 ppb.
"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," senior co-author Joel Kaufman, a professor of environmental and occupational health sciences and epidemiology in the School of Public Health at the University of Washington, said in a statement.
This is problematic. Efforts to reduce pollutants have seen most decline but the ozone continues to increase – in some areas by as much as 3 ppb, in part thanks to climate change. This is because ground-level ozone is generated when ultraviolet light interacts with fossil fuel pollutants.
"These findings matter since ground-level ozone levels are rising, and the amount of emphysema on CT scans predicts hospitalization from and deaths due to chronic lung disease," said senior author R. Graham Barr, a professor of medicine and epidemiology at Columbia University.
Emphysema is a chronic disease with no cure, although there are treatments to help manage the condition. Damage of lung tissue prevents the body from processing oxygen effectively, leaving patients with a persistent cough, trouble breathing, and at an increased risk of death.
"As temperatures rise with climate change," Barr continued, "ground-level ozone will continue to increase unless steps are taken to reduce this pollutant. But it's not clear what level of the air pollutants, if any, is safe for human health."