If you’ve ever wondered how interconnected the world really is, a new study offers a hint: Cutting smog levels in North America could actually save as many lives in Europe as here at home — perhaps more.

It’s one of several surprising findings in a study by atmospheric scientists, including one at UC Irvine, that combined computer models of the atmosphere with health statistics to assess how a major pollutant, ground-level ozone, might affect other nations in the northern hemisphere — and how their pollution might affect us.

For the most part, cutting ozone output had the biggest effect on death rates inside each of the regions studied — North America, East Asia, South Asia, and Europe. Overall, more than 30,000 lives a year could be saved worldwide if each of the four regions cut their ozone output by 20 percent, the study found.

The one exception was North America. As much as 76 percent of the deaths avoided by cutting ozone production would occur outside North America. Europe could benefit the most because of higher population levels and higher death rates, and because more smog flows to Europe from the North American continent than in the opposite direction.

For example, death rates from cardiopulmonary disease alone — only a portion of overall pollution-related deaths —  would drop by an estimated 900 per year in North America, but by 1,100 in Europe.

“I think this is a wakeup call,” said UC Irvine atmospheric modeler Michael Prather, one of the authors of the report. “This is one atmosphere, and we are making a mess of it.”

Much depends, however, on the assumptions put into the model, Prather said. Changing the math slightly, so that pollution deaths are only counted after a certain exposure threshold is reached, makes the lopsided gains by Europe disappear.

Still, all versions of the modeling suggest that cutting ozone in one region of the globe would likely benefit people far away, even in countries that produce comparatively little of the pollutant.

Scientists have known for years that dust and air pollution can be transported around the world — for example, pollution from China being detected on the U.S. West Coast. But most examples are isolated or incidental; the new study tries to pin down more precisely how ozone flows among major regions of the planet.

Ground-level ozone, a lung irritant that can make conditions like asthma worse, is produced when nitrogen oxides, much of it from car exhaust, and other contaminants are cooked by sunlight.

The study, “Intercontinental Impacts of Ozone Pollution on Human Mortality,” with lead author Susan Casper Anenberg, was published last week in Environmental Science and Technology.

(Register photo of O.C. traffic, generator of ozone precursors, by Paul E. Rodriguez.)

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