Credit: Carsten A. Skjøth Grass pollen is a major outdoor allergen, responsible for widespread and costly respiratory conditions including allergic asthma and hay fever (rhinitis). Now, researchers re-porting in the journal Current Biology on March 11 suggest that environmental DNA could help to better understand which grasses are the worst offenders. "These findings represent a first step towards changing and improving our understanding of the complex relationships between pollen and population health," said Benedict Wheeler of the University of Exeter, UK. "If confirmed and refined, this research could help to improve pollen forecasts and warnings in the future, supporting individual and community-level prevention strategies and management of healthcare system responses."