Air pollution levels from Deepwater Horizon spill similar to large urban area

Dec 20, 2011
The Deepwater Horizon site. Credit: NOAA

(PhysOrg.com) -- The amount of air pollutants in the atmospheric plume generated by the Deepwater Horizon oil spill was similar to a large city according to a new NOAA-led study published today in a special issue of Proceedings of the National Academy of Sciences.

Researchers from the Research Laboratory (ESRL) and NOAA’s Cooperative Institute for Research in Environmental Sciences (CIRES) in Boulder, Colo., along with university colleagues, focused on ozone and particulate matter—two pollutants with human health effects.

About eight percent, or about one of every 13 barrels of the Deepwater Horizon-spilled oil that reached the ocean surface, eventually made its way into airborne organic particles small enough to be inhaled into human lungs, and some of those particles likely reached the Gulf coast when the winds were blowing toward the shore, according to the study.

"We could see the sooty black clouds from the burning oil, but there’s more to this than meets the eye. Our instruments detected a much more massive atmospheric of almost invisible small organic particles and pollutant gases downwind of the oil spill site," said Ann M. Middlebrook, scientist at NOAA ESRL’s Chemical Sciences Division (CSD) and lead author of the study. 

According to the study, over the course of the spill, the total mass of organic particles formed from evaporating surface oil was about ten times bigger than the mass of soot from all the controlled burns. Controlled burns are used to reduce the size of surface oil slicks and minimize impacts of oil on sensitive shoreline ecosystems and marine life.

The organic particles formed in the atmosphere from hydrocarbons that were released as surface oil evaporated, and they got bigger as they traveled in the plume.  The atmospheric plume was about 30 kilometers wide– about 18.5 miles – when it reached the coast.

Some of the hydrocarbons from the evaporating oil reacted with nitrogen oxides in the atmosphere to create ozone pollution, but this other atmospheric plume was only 3 to 4 kilometers (2 to 3 miles) wide at the coast.

 “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, NOAA scientist at ESRL/CSD and a co-author of the study.

The relatively small amounts of nitrogen oxides in the vicinity of the oil spill (which included nitrogen oxides emitted by the spill cleanup and recovery efforts) limited the amount of polluting ozone that was formed offshore.  When the excess hydrocarbons reached the coast, they could have reacted with on-shore sources of , such as cars and power plants, to form additional ozone.

The researchers gathered data in June 2010 on two flights of NOAA’s WP-3D research aircraft that was outfitted to be a “flying chemical laboratory.” They also analyzed data gathered on ships in the vicinity and at two monitoring sites in Mississippi downwind of the oil spill.

They used a regional air quality model to project the path of the particle pollution, and found that time periods when the pollution plume was predicted to have reached the coast matched up well with a few short periods of high readings at the monitoring sites.

In addition to the that formed from the evaporating oil, soot particles were lofted into the atmosphere from the oil that was burned on the surface.

The authors note that their findings could help air quality managers anticipate the effects of future . The depth of the Deepwater Horizon spill, about a mile beneath the surface, limited the effects on air quality because some hydrocarbons, such as benzene, largely dissolved in the water.

“It was fortunate that the effects on of the Deepwater Horizon oil spill were limited in scope,” said Middlebrook. “Our findings show that an spill closer to populated areas, or in shallower waters, could have a larger effect.”

Explore further: US delays decision on Keystone pipeline project

More information: The new paper, Air Quality Implications of the Deepwater Horizon Oil Spill, has 25 co-authors from NOAA ESRL and CIRES. For more information, visit the Proceedings of the National Academy of Sciences website.

Related Stories

Recommended for you

US delays decision on Keystone pipeline project

Apr 18, 2014

The United States announced Friday a fresh delay on a final decision regarding a controversial Canada to US oil pipeline, saying more time was needed to carry out a review.

New research on Earth's carbon budget

Apr 18, 2014

(Phys.org) —Results from a research project involving scientists from the Desert Research Institute have generated new findings surrounding some of the unknowns of changes in climate and the degree to which ...

User comments : 1

Adjust slider to filter visible comments by rank

Display comments: newest first

Howhot
1 / 5 (1) Dec 21, 2011
I still remained shocked by the utter environmental devastation that this man made accident caused. I pretty much killed the gulf, and environmental groups are finding man dead sea creatures washed a shore than prior horizon.

During the oil spill, it was like having a large citys worth of pollution appear out in the middle of the Gulf of Mexico


Basically the gulf has areas that are still giant toxic swaths of Deephorizon poisoned ocean as far as the eye can see.

More news stories

China says massive area of its soil polluted

A huge area of China's soil covering more than twice the size of Spain is estimated to be polluted, the government said Thursday, announcing findings of a survey previously kept secret.

UN weather agency warns of 'El Nino' this year

The UN weather agency Tuesday warned there was a good chance of an "El Nino" climate phenomenon in the Pacific Ocean this year, bringing droughts and heavy rainfall to the rest of the world.

Easter morning delivery for space station

Space station astronauts got a special Easter treat: a cargo ship full of supplies. The shipment arrived Sunday morning via the SpaceX company's Dragon cargo capsule.

Hackers of Oman news agency target Bouteflika

Hackers on Sunday targeted the website of Oman's official news agency, singling out and mocking Algeria's newly re-elected president Abdelaziz Bouteflika as a handicapped "dictator".

NASA's space station Robonaut finally getting legs

Robonaut, the first out-of-this-world humanoid, is finally getting its space legs. For three years, Robonaut has had to manage from the waist up. This new pair of legs means the experimental robot—now stuck ...