In winter 2022, about fifty scientists from the United States and Europe completed a seven-week atmospheric chemistry study of Fairbanks, Alaska–the state’s second-largest city.
The study, called the Alaskan Layered Pollution and Chemical Analysis (ALPACA) project, investigated the chemistry of Fairbanks’s air pollution–especially how the pollution behaves in the cold and dark. Fine particulate pollution, which causes respiratory and heart illness, is a problem for the city. Since 2009, Fairbanks consistently exceeds the EPA air quality standard for particulate matter all winter. In fact, the city has the highest fine particulate, or PM2.5 concentration, in the United States.
Wood combustion for household heating is the largest single source of Fairbanks’s winter air pollution. Wood is cheaper than heating oil, and heating is essential as temperatures regularly reach minus 40 degrees Celsius. Additional pollution sources are coal and oil power plants, transportation, and light industry. Like other cities surrounded by mountains, Fairbanks experiences winter “inversions,” which are layers of warmer air aloft that trap cold, polluted air and prevent it from dispersing.
ALPACA scientists utilized many air sensors around the city to collect data, applying sensors indoors, on a trailer roof rack, and on the roof of the University of Alaska Fairbanks Community and Technical College.
U.S. researchers convened in Fairbanks for ALPACA. Credit: Lu Hu.
Now that data collection is complete, researchers are organizing and analyzing their measurements, and drawing conclusions. Researchers plan to deliver their results to University of Alaska Fairbanks by late summer 2022.
ALPACA was largely funded by the National Science Foundation. The NOAA Climate Program Office’s Atmospheric Chemistry, Carbon Cycle and Climate (AC4) program and European sources also contributed funding. For the AC4 program, ALPACA reflects NOAA’s continued focus on urban atmospheric composition.
“Given its constant evolution from changing pollution sources, and its significant effect on human health, urban atmospheric composition matters to scientists and the local Alaska population alike, ” said Monika Kopacz, AC4 program manager. “Studying air composition in the extreme cold and dark winter of Fairbanks, Alaska, can help us understand similar conditions in U.S. states with similar topography, as well as urban centers throughout the Arctic.”
AC4 is a competitive research program that incorporates research on atmospheric chemistry and the carbon cycle. In collaboration with the NOAA Laboratories and the academic community, the AC4 program supports research to determine the processes governing atmospheric concentrations of trace gases and aerosols in the context of the Earth System. The program aims to contribute a process-level understanding of the Earth System through observation, modeling, analysis, and field studies to support the development and improvement of models, and to inform carbon and air pollution management efforts.