Pennsylvania issued a code orange advisory for air quality for the Philadelphia and Susquehanna Valley regions Thursday because of high ozone levels.
Ozone that occurs naturally high in the atmosphere is a good thing—it protects Earth from UV radiation. But on air-quality alert days, high levels of ground-level ozone, or “bad” ozone, pose a problem for some at-risk people.
Ground-level ozone is not emitted into the air. It is created when the oxygen in oxides of nitrogen and volatile organic compounds, commonly found in car exhaust and emissions from industrial facilities and electric utilities, react with heat and sunlight to form unstable 03 molecules.
Ozone irritates the lining of the lungs and makes it harder to breathe.
“If you look at what the lungs are, they are a place for gasses to exchange,” said Gregory Busch, chief geriatrician for Virtua Health in New Jersey.
Lungs absorb oxygen and expel carbon dioxide, but oxidants—the opposite of those healthy antioxidants we look for in our food—get in the way of that process.
“Since ozone is an oxidant, it decreases the effectiveness of the lungs to take in regular O2 oxygen and to excrete C02, the byproduct of cellular metabolism,” Busch said.
Busch said children, the elderly and those with respiratory illnesses, such as asthma, emphysema and bronchitis, should limit outdoor activities on high ozone days.
Dr. Mani Kavuru, director of pulmonary and critical care at Thomas Jefferson University Hospital, said ozone also affects heart health.
“Cardiovascular disease is another area where there’s pretty good data that if you have days of high pollution, that correlates with increased visits to the emergency room, for example, with heart attacks and so forth,” Kavuru said.
On air-quality action days, the Pennsylvania Department of Environmental Protection calls for people to reduce pollution-causing activities by carpooling or taking public transit and washing only full loads of laundry and turning off lights in the home.