New Chemical Pathway in Air Quality in Cold Winters

• Shahzad Gani’s study from IIT Delhi suggests hydroxymethanesulphonate can form in fine particles in extremely cold, dark conditions.

• Fairbanks, Alaska’s capital, experiences low temperatures, reducing ammonium ions in aerosols, making it ideal for hydroxymethanesulphonate production.

• Fairbanks, a U.S. city, is among the U.S.’s worst-performing cities due to high PM2.5 levels.

• A 2022 directive banned the use of fuel with sulphur concentrations exceeding 1,000 parts per million in Fairbanks.

• James Campbell, a doctoral scholar at the University of Alaska Fairbanks, found that hydroxymethanesulphonate forms during winters in Fairbanks when formaldehyde and sulphur dioxide react with liquid water.

• The study combined measurements from the Alaska Layered Pollution and Chemical Analysis (ALPACA) project with thermodynamic modelling.

• The acidity of aerosol particles in Fairbanks changes rapidly during winter, making conditions more favorable for hydroxymethanesulphonate formation.