The novel coronavirus appears to linger in the air in crowded rooms that lack good ventilation, according to a new study from China. Bloomberg News reports that researchers, led by Ke Lan of Wuhan University, set up tests in and around two hospitals in the city where the outbreak began. Using so-called aerosol traps, they reportedly found bits of the virus’ genetic material floating in the air of rooms including hospital toilets, supermarkets, and residential buildings. Especially high concentrations were reportedly found in hospital rooms where medical staff were removing their protective gear. The study, published Monday in the journal Nature Research, didn’t conclude whether or not the floating particles can make people sick. The researchers said their findings show the importance of ventilation, limiting crowds, and meticulous cleaning.