In a study published in National Science Review, researchers present multiple lines of observational and modeling evidence for a ~4% decline in global atmospheric oxidation capacity in 2020, reflected by a drop in hydroxyl radical (OH) concentrations. Using satellite-based carbon monoxide data, as well as methane and methyl chloroform observations, the study reveals that this OH reduction occurred in both hemispheres—approximately 2.4% in the Northern Hemisphere and 5.7% in the Southern Hemisphere—driven by distinct mechanisms. In the Northern Hemisphere, reduced NO_x emissions due to COVID-19 lockdowns led to lower OH and tropospheric ozone levels, while in the Southern Hemisphere, massive emissions of reactive carbon from unprecedented Australian wildfires caused OH depletion but tropospheric ozone increases. This contrast in tropospheric ozone anomalies is further corroborated by satellite data. The findings help explain one of the record-breaking rises in atmospheric methane in 2020 and underscore the critical role of both natural and anthropogenic factors in shaping Earth’s atmospheric chemistry and global methane budget.

People who have survived cancer as children are at higher risk of developing severe COVID-19, even decades after their diagnosis. This is shown by a new study from Karolinska Institutet published in the journal The Lancet Regional Health – Europe.

A new study challenges the belief in a universal “pet effect” on human well-being. Using data collected during COVID-19 lockdowns, researchers found no significant change in respondents' well-being when they acquired or lost a pet in their household. The findings suggest that, even during a time of extreme isolation, human-animal bonds may not be as emotionally transformative as we like to believe.

Four discrete cross-sectional surveys of US adults from 2020-2024 reveal US adults reporting high confidence in the Centers for Disease Control and Prevention (CDC) dropped from 82 percent in February 2020 to a low of 56 percent in June 2022, according to a study published June 26, 2025 in the open-access journal PLOS Global Public Health by Amyn A. Malik and colleagues from UT Southwestern Medical Center, United States.