"The levels of ozone were similar to what occurs in large urban areas. During the oil spill, it was like having a large city's worth of pollution appear out in the middle of the Gulf of Mexico," said Daniel M. Murphy, National Oceanographic Atmospheric Administration scientist and a co-author of the study.
The researchers gathered data in June 2010 on two flights of a NOAA research aircraft over the Gulf of Mexico outfitted to be a "flying chemical laboratory," an agency release said Tuesday.
The research focused on ozone and particulate matter, two pollutants with human health effects.
About 8 percent, or about one of every 13 barrels of the spilled oil that reached the ocean surface, made its way into airborne organic particles small enough to be inhaled into human lungs, the researchers said.
The findings could help air quality managers anticipate the effects of future oil spills, they said.
The depth of the Deepwater Horizon spill, about a mile beneath the surface, limited the effects on air quality because some hydrocarbons largely dissolved in the water.
"It was fortunate that the effects on air quality of the Deepwater Horizon oil spill were limited in scope," lead study author Ann M. Middlebrook of NOAA said. "Our findings show that an oil spill closer to populated areas, or in shallower waters, could have a larger effect."