Recently, more than 1,500 of the world’s preeminent aerosol scientists gathered in St. Louis for the 10th International Aerosol Conference (IAC). Held every four years — and only every 12 years in the United States — the event took place Sept. 2-7 at the Americas Center. The conference was opened by Chancellor Mark S. Wrighton, who welcomed the attendees from 48 different countries to St. Louis.