Pollution has always been thought to reduce survival due to its noxious effects on people’s health. Previous studies have linked pollution to increased risk of heart attack, stroke, lung cancer, asthma and other serious diseases.

A study published in Thursday’s New England of Medicine shows that people who live in areas with the most ozone pollution are 25 percent to 30 percent more likely to die from lung disease than those living in areas with the cleanest air.

Ozone is a form of oxygen, which acts as a shield against harmful ultraviolet rays from the Sun, if it is high in the atmosphere. If it is on the ground level, ozone can cause lung damage, trigger asthma attacks and worsen heart disease. Children and elderly are at high risk.

The current study was the work of Michael Jerrett of the University of California and his colleagues. Together, they studied nearly 500,000 people across the United States for 18 years and found that 118,777 people died over this period.

To be more specific, each additional 10 parts per billion of ozone concentration was linked to a 4 percent increased risk of dying from respiratory causes, most notably pneumonia and chronic obstructive pulmonary disease.

The study is the first to show that long-term, low-level exposure to the pollutant can also be lethal.

“We now know that controlling ozone is not only beneficial for mitigating global warming, but that it could also have near-term benefits in the reduction of deaths from respiratory causes,”  Jerrett said.

About 240,000 people in the United States and 7.7 million people worldwide die of respiratory disease each year, according to data from the World Health Organization.