CAMBRIDGE, Mass., Sept. 5 (UPI) -- Flights over the Pacific, specifically leaving and entering Australia and New Zealand, create the most ozone, a new study says.
Conducted by Massachusetts Institute of Technology, the study was published Thursday in IOP Publishing's journal, Environmental Research Letters.
The study, which analyzed around 83,000 individual commercial flights, pinpointed a specific area over the Pacific approximately 621 miles to the east of the Solomon Islands that is the most sensitive to aircraft emissions.
In that region of the Pacific, researchers estimated that each 2.20 pounds of aircraft emissions -- specifically oxides of nitrogen, or NOx, such as nitric oxide and nitrogen dioxide – produces an extra 33 pounds of ozone in one year.
The sensitivity in the area was about five times higher than the sensitivity in Europe and 3.7 times higher than the sensitivity in North America, the study says, noting that the Pacific region is particularly vulnerable to aircraft emissions because it is relatively pristine, with little preexisting levels of nitrogen oxides.
"Our findings show that the cleanest parts of the atmosphere exhibit the most dramatic response to new emissions," said Steven Barrett, a professor at MIT and the lead author of the study, in a statement. "New emissions in this part of the Pacific will result in a relatively larger response from the atmosphere."
Overall, the study says, flights in the region in October cause 40 percent more NOx emissions than flights in April.
The researchers also found that the 10 highest ozone-producing flights originated from or were destined for New Zealand or Australia.
For example, a flight from Sydney to Bombay produced 56 pounds of ozone, the highest amount in the study, because the majority of the flight passed through the area in the Pacific where the sensitivity was the highest.
Barrett suggested that airlines could achieve reductions in their climate impact by re-routing planes to avoid sensitive areas.
"The places that the sensitivities are highest now are the fastest growing regions in terms of civil aviation growth, so there could potentially be ways to achieve significant reductions in the climate impact of aviation by focusing on re-routing aircraft around the particular regions of the world where ozone formation is highly sensitive to NOx emissions," he said.
The European Commission has projected that by 2020, global international aviation emissions might be around 70 percent higher than in 2005, even though there have been improvements in fuel efficiency. It projects that those emissions could grow by 300 to 700 percent by 2050.