Nav: Home

Method of tracking reactions between air and carbon-based compounds established

February 26, 2018

By being the first to fully track the changing chemistry of carbon molecules in the air, a Virginia Tech professor could change the way we study pollutants, smog, and emissions to the atmosphere.

Gabriel Isaacman-VanWertz, lead scientist on a new study published in Nature Chemistry and assistant professor in Virginia Tech's department of civil and environmental engineering, has established a method of tracking reactions between air and carbon-based compounds -- a feat that has been previously elusive to researchers.

This new finding could allow researchers to study pollution, smog, and haze in a comprehensive way, backed by data that accurately depicts a compound's behavior over time.

"There are tens of thousands of different compounds in the atmosphere," Isaacman-VanWertz said. "In general, the focus of my work is to study the chemistry of how those tens of thousands of compounds interact with each other and change with time."

When a certain compound is introduced into the atmosphere, it chemically reacts to form other compounds and molecules over time, explains Isaacman-VanWertz, who began this research as a post-doctoral research fellow at the Massachusetts Institute of Technology with study co-author Jesse Kroll.

Isaacman-VanWertz is particularly focused on studying the way the atmosphere interacts with organic compounds -- the carbon-containing compounds that make up all living things. Large amounts of these compounds are emitted from natural sources and human activities.

Anything with a scent emits organic compounds: citrus, vinegar, nail polish remover, and gasoline, for example. Once these emitted compounds enter the atmosphere, they change in complex ways to form hundreds or thousands of other compounds.

Previously, tracking the way the carbon changes once it enters the atmosphere has been a challenge. Thanks to tools developed in the past decade, this study found that complete measurement of carbon in the atmosphere is now possible, though it still requires state-of-the-art instruments and careful analysis.

For this project, Isaacman-VanWertz studied the smell of pine, which is made of an organic compound known as pinene.

Isaacman-VanWertz and his collaborators at MIT used five spectrometers -- advanced pieces of equipment that classify chemicals by their masses and the atoms they contain -- to measure the characteristics of carbon inside a Teflon bag the height of a person in a climate-controlled, blacklight-outfitted room.

When they turned on the blacklights, it was like turning on the sun, Isaacman-VanWertz said. The light of the "sun" spurred the chemistry of the pinene inside the chamber and simulated the reactions that would occur in the atmosphere.

Each spectrometer was tasked with collecting a certain set of data throughout the elapsed reaction, like tracking specific ranges of chemical compounds. One of the hardest parts of this experiment was putting all of these measurements on the same scale, Isaacman-VanWertz said. Understanding the specific details and measurements of each instrument can be so complex, he said, there are doctoral students writing entire theses on these topics.

Isaacman-VanWertz and his collaborators were able to, for the first time, fully track the carbon in the pinene molecules from start to finish as they underwent chemical changes as they would in the atmosphere. The carbon atoms in pinene do not disappear after their initial introduction to the atmosphere -- they turn into hundreds of different compounds through a cascade of chemical reactions.

Although the initial mixture of compounds formed from reactions of pinene is very complex, all the carbon was found to end up in "reservoirs" that are relatively stable and won't react further in the atmosphere.

What's more, the process is likely similar for other carbon-based compounds. Isaacman-VanWertz picked pinene because it has been extensively studied, so he could use previous work to make sense of his observations.

Though pinene is naturally emitted, its behavior is comparable enough to better anticipate the way other compounds, like those in pollutants, smog, and haze, will react in the air. Understanding this helps "paint a big picture of the atmosphere," Isaacman-VanWertz said.

For example, these results will help other researchers understand how pollutants from a power plant might transform in the atmosphere and impact a downwind community.

"If you can understand how the chemistry happens, then you can understand what sorts of pollutants will be in the atmosphere based on how far from a polluting source you are," Isaacman-VanWertz explained.

Isaacman-VanWertz hopes other researchers will build upon the results of this study. He wants to know whether the tendency of emitted compounds to end up as long-lived atmospheric components is generally applicable to other compounds and how this process might coexist or compete with other processes occurring in the atmosphere.

Virginia Tech

Related Atmosphere Articles:

Primitive atmosphere discovered around 'Warm Neptune'
A pioneering new study uncovering the 'primitive atmosphere' surrounding a distant world could provide a pivotal breakthrough in the search to how planets form and develop in far-flung galaxies.
NASA's MAVEN reveals Mars has metal in its atmosphere
Mars has electrically charged metal atoms (ions) high in its atmosphere, according to new results from NASA's MAVEN spacecraft.
Northern oceans pumped CO2 into the atmosphere
The Norwegian Sea acted as CO2 source in the past.
Study opens new questions on how the atmosphere and oceans formed
A new study led by The Australian National University has found seawater cycles throughout the Earth's interior down to 2,900km, much deeper than previously thought, reopening questions about how the atmosphere and oceans formed.
How a moon slows the decay of Pluto's atmosphere
A new study from the Georgia Institute of Technology provides additional insight into relationship between Pluto and its moon, Charon, and how it affects the continuous stripping of Pluto's atmosphere by solar wind.
Fossil fuel formation: Key to atmosphere's oxygen?
For the development of animals, nothing -- with the exception of DNA -- may be more important than oxygen in the atmosphere.
Researchers dial in to 'thermostat' in Earth's upper atmosphere
A team led by the University of Colorado Boulder has found the mechanism behind the sudden onset of a 'natural thermostat' in Earth's upper atmosphere that dramatically cools the air after it has been heated by violent solar activity.
New biochar model scrubs CO2 from the atmosphere
New Cornell University research suggests an economically viable model to scrub carbon dioxide from the atmosphere to thwart global warming.
Venus-like exoplanet might have oxygen atmosphere, but not life
The distant planet GJ 1132b intrigued astronomers when it was discovered last year.
Middle atmosphere in sync with the ocean
In the late 20th century scientists observed a cooling at the transition between the troposphere and stratosphere at an altitude of about 15 kilometers.

Related Atmosphere Reading:

Best Science Podcasts 2019

We have hand picked the best science podcasts for 2019. Sit back and enjoy new science podcasts updated daily from your favorite science news services and scientists.
Now Playing: TED Radio Hour

Jumpstarting Creativity
Our greatest breakthroughs and triumphs have one thing in common: creativity. But how do you ignite it? And how do you rekindle it? This hour, TED speakers explore ideas on jumpstarting creativity. Guests include economist Tim Harford, producer Helen Marriage, artificial intelligence researcher Steve Engels, and behavioral scientist Marily Oppezzo.
Now Playing: Science for the People

#524 The Human Network
What does a network of humans look like and how does it work? How does information spread? How do decisions and opinions spread? What gets distorted as it moves through the network and why? This week we dig into the ins and outs of human networks with Matthew Jackson, Professor of Economics at Stanford University and author of the book "The Human Network: How Your Social Position Determines Your Power, Beliefs, and Behaviours".