According to new research that seeks to better understand the causes and makeup of the dirty air, a chemical compound discovered in Fairbanks' wintertime air in 2019 accounts for a significant portion of the community's fine particulate pollution.
|In this 2006 photograph taken from the University of Alaska Fairbanks, ice fog settles over Fairbanks. Debbie Dean took the photo at UAF.|
The discovery is the first measurement of the amount of hydroxymethanesulfonate, or HMS, in the air in Fairbanks.
During pollution episodes, the compound accounted for 3% to 7% of the total amount of particles smaller than 2.5 micrometers, or PM 2.5. This amount is significantly higher than previously observed, leading the research team to conclude that Fairbanks' extremely low temperatures play a role in the compound's formation.
"People in the community are completely unaware of this," said Jingqiu Mao, the study's principal investigator. "We believe it is critical to inform the Fairbanks community about this new chemical compound."
"We know very little about the health effects of hydroxymethanesulfonate," he said. "In the atmospheric chemistry and air quality communities, this compound is novel. We had no idea this compound was so abundant."
The study was published in Environmental Science & Technology in May and was written by James Campbell, a graduate student of Mao's. Scientists from the University of Alaska Fairbanks Geophysical Institute, the Georgia Institute of Technology, Johns Hopkins University, and NASA's Goddard Space Flight Center collaborated on the project.
The study is the first result of a three-year National Science Foundation grant.
Fairbanks has been working for years to improve its wintertime air quality, as mandated by the US Environmental Protection Agency. Noncompliance will result in penalties for both the community and the state.
The new HMS discovery is also significant because previous research has shown that hydroxymethanesulfonate can be easily misidentified as sulfate, potentially rendering previous air pollution measurements inaccurate. Studying HMS also allows for a better understanding of other chemical reactions in Fairbanks' ambient aerosols during the winter months.
Knowing the exact composition of fine particulate matter pollution is critical for implementing appropriate air quality control measures, according to Mao.
"A variety of sources contribute to PM 2.5," he explained. "But, when it comes to improving air quality, which aspect should be prioritized? What are the ramifications of this?"
The team studied the air in Fairbanks during two winters: January to March 2020 and December 2020 to February 2021. Data came from instruments near the University of Alaska Fairbanks Community and Technical College in downtown Fairbanks, as well as a nearby state Department of Environmental Conservation site that already measured total PM2.5, sulfur dioxide, and temperature.
Scientists have long suspected that hydroxymethanesulfonate is formed by the reaction of sulfur dioxide and formaldehyde, which combine when attracted to liquid particles in the atmosphere.
However, scientists do not know to what extent factors such as atmospheric droplet acidity, temperature, and humidity contribute to HMS formation.
They also don't know which source is to blame for the formation of HMS in Fairbanks. Sulfur dioxide is produced by the combustion of fossil fuels such as heating oil and coal. Formaldehyde is most likely released into the atmosphere by burning wood.
According to studies, wood smoke contributes 40% to 70% of the wintertime PM2.5 mass concentration in Fairbanks.
"Fairbanks is one of the few ideal locations for HMS formation," Mao explained. "And that isn't always a good thing."
Reference: DOI: 10.1021/acs.est.2c00410