Concentrations of small-particle sulfates (IMAGE) Hokkaido University Caption Concentrations of small-particle sulfates were three times higher in the 1970s compared to the 2010s, while the concentrations of large-particle sulfates were relatively unchanged (Yoshinori Iizuka, et al. Journal of Geophysical Research: Atmospheres. September 16, 2022). Credit Yoshinori Iizuka, et al. Journal of Geophysical Research: Atmospheres. September 16, 2022 Usage Restrictions This image can be used for reporting purposes without obtaining permission if credited properly. License Original content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.