Scientists have so far considered two primary routes for transmitting SARS-CoV-2, the virus that causes COVID-19 (coronavirus): contact with an object that has the virus on it, or inhalation of micro-droplets emitted through sneezes and coughs.

Usually that means touching an object covered in the micro-droplets, but they can even suspend themselves in the air, so sneezes and coughs effectively blow around droplets containing SARS-CoV-2, the virus that causes COVID-19.

In this image taken with a high-sensitivity video camera, micro-droplets travel through the air after a man sneezes.

Although it's unclear what volume of micro-droplets could cause the virus to spread, Tateda says they've almost certainly contributed to more cases.

Opening a window or turning on fans could help sweep away these micro-droplets, the scientists believe, because they're so small and light