Harvard Researchers Find Purest Air

For the first time, scientists have isolated pure air particles of nearly pre-industrial conditions.
Harvard Researchers Find Purest Air
Birds fly over the Amazon rain forest near the Solimoes River on Nov. 25, 2009, near Manaquiri, Brazil. (Antonio Scorza/AFP/Getty Images)
Conan Milner
9/30/2010
Updated:
10/1/2015
<a><img src="https://www.theepochtimes.com/assets/uploads/2015/09/ar93423656.jpg" alt="Birds fly over the Amazon rain forest near the Solimoes River on Nov. 25, 2009, near Manaquiri, Brazil.  (Antonio Scorza/AFP/Getty Images)" title="Birds fly over the Amazon rain forest near the Solimoes River on Nov. 25, 2009, near Manaquiri, Brazil.  (Antonio Scorza/AFP/Getty Images)" width="320" class="size-medium wp-image-1813994"/></a>
Birds fly over the Amazon rain forest near the Solimoes River on Nov. 25, 2009, near Manaquiri, Brazil.  (Antonio Scorza/AFP/Getty Images)
For the first time, scientists have isolated pure air particles of nearly pre-industrial conditions. The discovery offers valuable insights into cloud formation and climate change.

Essentially, the particles emitted by plants allow cooling clouds to form. Understanding the process, which had not been observed before, would permit a clearer understanding of climate.

Environmental engineers working in the remote Amazonian Basin north of Manaus, Brazil, measured air particles that were formed within the rain forest ecosystem.

Researchers from Harvard and São Paulo University (USP) chose these relatively pure, isolated air particles because they may provide important clues in determining the specific chemical differences between natural and polluted environments. The findings are published in the Sept. 16 issue of the journal Science.

To measure these pure air particles, scientists took samples from a 130-foot tower during Amazonia’s rainy season, to avoid the contamination from burning and deforestation that occurs during the region’s dry months. They chose submicron particles as the most relevant to climate. These small particles came from the atmospheric oxidation of plant emissions.

During their study, the researchers detected rain forest aerosol particle concentrations of a paltry several dozen per cubic inch. In industrialized cities, particle concentrations of several thousand per cubic inch are found.

Surprisingly, researchers found that these pure droplets comprised over 85 percent of the climate-relevant submicron particles in the air over the Amazon rain forest. Scientists say the low aerosol concentrations and high concentration of secondary organic air particles suggest that particle interplay, clouds, and precipitation is quite different in pristine climate systems than in polluted ones.

“Those particles are affecting cloud formation and cloud formation is affecting precipitation which is affecting the plants. This is what we call the great tropical reactor,” said lead author Scot Martin, Gordon McKay Professor of Environmental Chemistry at the Harvard School of Engineering and Applied Sciences (SEAS) in a press release.

“Everything is connected and in our research we finally had a real glimpse of natural aerosol-cloud interactions.”

Researchers explain that when plants emit gas-phase molecules into the atmosphere, these volatile particles don’t last for long. The gas-phase molecules are changed when they come in contact with ozone or hydroxyl radicals, making them exceedingly less volatile.

These either condense to form new particles or grow pre-existing particles to serve as the nuclei on which atmospheric water condenses as climate-important clouds form. While scientists have long been aware of this cycle, they haven’t yet been able to create an accurate quantitative understanding of the sources of these aerosol particles.

This study offers researchers a better understanding of global climate by providing a baseline with a pristine particle to contrast to current industrial air quality.

“The new insights and data help us and our colleagues to understand and quantify the interdependence of the cycling of aerosols and water in the unperturbed climate system,” explains lead co-author Ulrich Pöschl, a scientist at the Max Plank Institute for Chemistry in Mainz, Germany, in a statement.

“A thorough understanding of the unperturbed climate system is a prerequisite for reliable modeling and predictions of anthropogenic perturbations and their effects on global change.”
Conan Milner is a health reporter for the Epoch Times. He graduated from Wayne State University with a Bachelor of Fine Arts and is a member of the American Herbalist Guild.
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