December 15, 2021

Dr. Jason Surratt

Dr. Jason Surratt

Jason Surratt, PhD, will serve as the University of North Carolina at Chapel Hill’s principal investigator on a large National Science Foundation-funded project to determine the content of airborne particulate matter, which has significant effects on health and climate change.

Dr. Nga Lee "Sally" Ng

Dr. Nga Lee “Sally” Ng

Georgia Institute of Technology Professor Nga Lee “Sally” Ng, PhD, is the lead principal investigator for the grant, which will provide high time-resolution, long-term measurements of the properties of atmospheric particulates known as aerosols. The award will establish a network of 12 sites around the United States, including locations in national parks and in some of the country’s largest cities. Each will be outfitted with state-of-the-art instruments for characterizing the properties of aerosols. Together, these sites will form the Atmospheric Science and mEasurement NeTwork (ASCENT).

Surratt is a professor in both the Department of Environmental Sciences and Engineering at the UNC Gillings School of Global Public Health and the UNC Department of Chemistry. He will lead a group tasked with installing, operating and analyzing aerosol equipment at the ground site in the Great Smoky Mountain National Park at Look Rock, Tennessee.

Data from ASCENT will allow researchers to address a variety of questions about how the composition and abundance of aerosols are changing, such as how the modernization of electrical production (coal to natural gas to renewable) and transportation (gasoline to electric vehicles) affect air pollution and climate-relevant variables.

“Each site will be equipped with a suite of advanced aerosol instrumentation, including a ToF-Aerosol Chemical Speciation Monitor, Xact instrument (for trace metals), Aethlatometer (for black/brown carbon) and a new Scanning Mobility Particle Sizer,” Surratt said. “Right now, only Europe and China have such a network of real-time aerosol composition and size. This will allow the U.S. to have a similar network setup here, which will help us to understand how climate change and changing emissions are affecting aerosol composition, size and physical properties. This will be hugely important to regional- and global-scale atmospheric chemistry and climate models.”

ASCENT will also advance understanding of the adverse health impacts of PM2.5 (particulate matter with a diameter smaller than 2.5 micrometers). Exposure to PM2.5 has been associated with cardiopulmonary diseases and millions of deaths per year.

“ASCENT’s long-term, advanced chemical composition and particle size measurements will facilitate transformative studies to unravel specific aerosol types and properties responsible for adverse health effects,” said Ng. “This will contribute to building a foundation to define future regulations in the U.S. for protecting public health, as aerosol sources and properties continue to evolve in a changing world.”

Smog hovers over Yellowstone National Park.

Smog hovers over Yellowstone National Park.

Aerosols impact climate by changing the earth’s energy balance via direct absorption or scattering of solar radiation as well as altering the surface reflection, formation of clouds and precipitation. The Intergovernmental Panel on Climate Change assessment established that the aerosol effects represent the single largest source of uncertainty in understanding climate change.

According to NSF, ASCENT also will allow U.S. researchers to remain competitive in a global research environment. The 2016 National Academies report on The Future of Atmospheric Chemistry Research emphasized the critical need for long-term atmospheric chemistry measurements, recommending that the NSF take the lead to establish synergies with existing sites.

On the education and outreach side of the project, ASCENT has specific recruitment, mentoring, training and career development plans for graduate and undergraduate students, with an emphasis on underrepresented groups. One of the ASCENT locations is on tribal land and the project will train tribal air quality staff and perform outreach to interested tribal members.

In collaboration with the National Center for Atmospheric Research, a comprehensive database and web interface will be developed to provide research communities, educators, policy makers, the public, etc. with free and open access to all ASCENT data.

Contact the UNC Gillings School of Global Public Health communications team at

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