Due to climate change, plants' pollination season has been growing longer and longer. As a result, people are exposed to allergens for extended periods each year, raising a major public health concern. Researchers from Embry‑Riddle Aeronautical University, the University of Rouen Normandy and the University of Lille have developed an advanced computational model of outdoor airflow through trees. They recently used it to study how a tree's geometry affects the dynamics and dispersion of its airborne pollen grains. The work appears in Physics of Fluids.