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Emphysema is considered a smoking disorder. However, it turns out that exposure to air pollution can cause the same changes in the lungs that lead to emphysema.
A recent study published today in JAMA finds that long-term exposure to slightly elevated levels of air pollution is associated with the accelerated development of lung injury, even in humans, who have never smoked.
The study looked at the health effects of inhaling various pollutants, including ground-level ozone, the main component of smog.
The researchers found that people in the study who were exposed to above-average levels of ground-level ozone for years developed similar lung changes to smokers.
"We have found that an increase of approximately three parts per billion [of ground-level ozone] outside your home for 29 years equals smoking one pack of cigarettes a day," says study author Joel Kaufman, a physician and epidemiologist at the University of Washington.
The study involved nearly 7,000 adults living in six US cities: Chicago, Los Angeles, Baltimore, St. Paul, Minnesota, New York City, and Winston-Salem, NC. In general, subjects were exposed to average annual concentrations of between 10 and 25 parts per billion of ground-level ozone outside their homes.
cities. According to Kaufman, people in US communities may be exposed to similar concentrations – which may vary from day to day, season to season and year to year. In general, ground-level ozone – or smog – forms when pollution from the exhaust pipes and chimneys of cars in sunlight. (The EPA has this simple explanation.) Ozone is usually highest on hot, sunny days.
"It was a big surprise to us that the effects were of the same order of magnitude as smoking cigarettes, which is the best." To assess the changes in the participants' lungs, each person had more than one Decade up to five CT scans. " These scans provide a 3D image of the lungs and can detect changes that precede the development of symptoms, and at the same time, researchers measured pollution levels, including ozone, in participants' communities. 19659008] "When the airways become narrowed and damaged, it's harder to get air out of the lungs and there are air pockets," said Emily Brigham, a lung researcher and assistant professor of medicine at Johns Hopkins University, who was not on the study but also explores how environmental influences can affect lung health.
In the early stages of respiratory disease w People may not notice much. But over time, these changes lead to emphysema symptoms, including shortness of breath. "It gets worse over time as you continue exposing," says Brigham. And the changes are generally considered irreversible.
Chronic respiratory disease (including chronic obstructive pulmonary disease and pulmonary emphysema) is a. The World Health Organization estimates that 7 million premature deaths around the world are related to air pollution each year.
These new findings help answer a very important question about COPD, says Brigham.
"We know … that a significant portion of the US population suffering from COPD is never a smoker," says Brigham. So, what causes your lung disease? "I think this [study] gives us a partial answer."
Overall, most types of air pollution in the US have declined, thanks in part to the guidelines introduced by the Clean Air Act.
But ground-level ozone – or smog – was harder to control. One explanation for this is that the conditions for the formation of ozone are more favorable as the number of hot days increases.
"As climate change advances, we expect more vulnerable populations, and even healthy populations, to be affected," says Brigham.
In the past, the short-term aggravation of symptoms on days with smog alarm was the biggest concern for ozone for people with chronic lung conditions such as asthma or COPD. The effects of long-term chronic exposure were not well known.
"In the past, the EPA has not accepted that COPD is caused by long-term chronic air pollution," says George Thurston, professor of environmental medicine at NYU Langone Health.
Now, however, this study adds to the evidence that the benefits of air purification are even greater than previously calculated, as the results suggest that long-term exposure to air damages lung health.
Thurston says that if these long-term cumulative effects were incorporated into policy makers' cost-benefit calculations, "the benefits outweigh the cost of further air purification".