ScholarlyArticle: "Impacts of antibiotic use, air pollution and climate on managed honeybees in Canada" (2025) https://www.nature.com/articles/s41893-025-01603-y :

> Abstract: [...] Notably, this decrease was inversely associated with rising overwintering mortality rates, suggesting that withdrawal of antibiotics in the absence of effective alternatives may negatively impact colony health. Furthermore, multivariate analysis accounting for environmental confounders (based on 119,244 data points collected from 234 unique locations across Canada) identified nitrogen dioxide (NO2), a common air pollutant from diesel exhaust, as a strong predictor of mortality. This finding warrants urgent attention given that NO2 can degrade floral odours, rendering them undetectable to honeybees during foraging flights.