Aerosol on EARTH Magazine

New global volcanic emissions map debuts

Mon, 19 Jun 2017 20:39:47 -0400

Volcanic sulfur dioxide emissions measured by the Aura satellite are shown in shades of orange in this map of Alaska's Aleutian Archipelago. Credit: Jesse Allen/NASA Earth Observatory.

Volcanoes may not always be erupting ash or lava, but that doesn’t mean they’re not venting other materials. Many, in fact, continuously spew gases like carbon dioxide and sulfur dioxide into the air. In a new study, volcanologists compiled data tracking such releases, collected by NASA’s Aura satellite, into the first global map of volcanic sulfur dioxide emissions.

To cool the planet, volcanoes of the future will need more firepower

Tue, 07 Feb 2017 14:29:46 -0500

On June 15, 1991, Mount Pinatubo sent a plume up 40 kilometers into the stratosphere. Credit: David H. Harlow, USGS.

Explosive volcanic eruptions can spew sulfur gas into the stratosphere — the layer of the atmosphere above where most clouds and weather occur — where it forms sulfate aerosols that reflect sunlight back into space and cool the planet. Now, researchers investigating how volcanic plumes could be affected by projected anthropogenic warming have found that, as temperatures rise, it becomes more difficult for volcanic plumes to reach the stratosphere.

Clouds can form without particles

Tue, 13 Sep 2016 14:25:29 -0400

Federico Bianchi and his colleagues analyzed air samples at Jungfraujoch Research Station in the Swiss Alps to study the formation of cloud condensation nuclei from organic compounds in the troposphere. Credit: Federico Bianchi.

In addition to their aesthetic and photogenic appeal, clouds play a crucial role in Earth’s climate and ecosystems, helping regulate temperatures by reflecting sunlight. All clouds — from fluffy cumulus to wispy cirrus — grow from seeds that, more often than not, are tiny particles of pollen, dust or chemical aerosols that float into the atmosphere from Earth’s surface. Sulfuric acid, a byproduct of volcanic eruptions and fossil fuel combustion, is one of the most ubiquitous precursors to atmospheric aerosols today and has long been thought to play a major role in modern cloud formation. But what about earlier in Earth’s history, before humans impacted the atmosphere as much? Three new studies, representing both experimental and field data, suggest that the planet’s plants and trees might have done just fine on their own pumping cloud-forming aerosols into the skies.

Volcanic aerosols not enough to cause mass extinctions?

Fri, 19 Feb 2016 18:35:29 -0500

Fresh basaltic lava degasses in the Holuhraun lava field in January 2015. The months-long Holuhraun eruption is a modern analog, albeit on a much smaller scale, of ancient flood basalt eruptions. Credit: Anja Schmidt, University of Leeds.

Mass extinctions — when more than half of Earth’s species disappear in a geologic instant — offer some of the planet’s most perplexing unsolved mysteries. Prolonged periods of volcanic activity have long been prime suspects for these ancient whodunits, the most recent of which finished off the last nonavian dinosaurs at the close of the Cretaceous about 66 million years ago. But scientists debate how drastic the environmental effects of such volcanism might have been, and whether other factors — like asteroid impacts, as in the end-Cretaceous extinction — played a big role as well.

Marine microorganisms drive summer clouds over Southern Ocean

Fri, 23 Oct 2015 11:43:18 -0400

Organic material lofted into the atmosphere with sea spray is a major source of cloud condensation nuclei over the Southern Ocean, particularly in the summer months when phytoplankton bloom prolifically. Credit: Daniel McCoy.

The Southern Ocean surrounding Antarctica is home to some of the most pristine air anywhere on Earth. And yet it’s also one of the cloudiest places on the planet, a seeming contradiction because water droplets require particulate matter in the air to condense into clouds. Now, a study looking at cloud droplet concentrations over the Southern Ocean is giving scientists a clearer understanding of the role played by marine microorganisms in cloud formation and climate.

Secondary aerosols a primary cause of Chinese smog

Mon, 05 Jan 2015 10:31:29 -0500

Taken one day apart — on Jan. 31 (top) and Feb. 1, 2013 (bottom) — these photos of Beijing's National Stadium hint at the scale of China's pollution problem. Credit: both: Ru-Jin Huang and Jun-Ji Cao.

Images of Chinese skylines and streetscapes blurred by pollution-fueled hazes have become increasingly common in recent years amid ongoing urbanization and industrialization. According to a new study published in Nature, much of the pollution fogging the country’s major cities is arising not from fine particles emitted directly into the sky, but by gases that react and condense in the atmosphere to form secondary aerosols.

For cloud formation, a little aerosol goes a long way

Wed, 03 Sep 2014 08:33:16 -0400

Clouds play a starring role in creating and controlling climate, but cloud physics are notoriously difficult to model, leaving wide gaps in understanding how cloud conditions have changed since the pre-industrial era. A new study looking at pristine regions of the sky in the South Pacific is shining some much-needed light on how particulate air pollution interacts with water vapor to form clouds.

Hurricanes suppressed by air pollutants

Tue, 25 Jun 2013 21:41:29 -0400

Understanding how often devastating tropical storms like Superstorm Sandy occur, and how humans may play a role in their frequency, is a major goal among climate scientists. Now, a new study indicates that aerosols may suppress storm formation over the Atlantic. Thus, researchers say, more frequent storms at the end of the last century might have been an unintended side effect of cleaning up the air.

Air pollutants from "megacities" a growing problem

Thu, 05 Jan 2012 06:41:58 -0500

Researchers in a mobile air quality research lab, with a rare morning view of Mexico City not covered in smog. Charles Kolb, Aerodyne Research Inc.

Megacities — cities with populations equaling or greater than 10 million people — are producing an unprecedented amount of air pollution, according to scientists at the American Chemical Society's annual meeting in Washington, D.C., on Tuesday.

Blogging on EARTH: Controversy over the weekend effect

Thu, 05 Jan 2012 06:41:58 -0500

Meg Marquardt, pictured in Muir Woods in California, is an intern at EARTH. Meg Marquardt

It’s Friday: Is it raining where you are?

Natural dust may be harmful to ocean organisms

Thu, 05 Jan 2012 06:41:58 -0500

Although human-made aerosols sometimes are toxic, natural aerosols from deserts and volcanoes are important contributors to ocean fertilization. Now, new research suggests that natural aerosols have their downside too — and the impact of natural aerosols on ocean organisms could influence predictions of future climate change.