Coronavirus: Can we stay safe as lockdown eases?

The most obvious is distance. Research that began in the 1930s showed that when someone coughs, most of the droplets they release either evaporate or fall to the ground within about one metre. That's why the World Health Organization (WHO) settled on its 'one metre' rule for social distancing. Some governments have opted for a safer limit of 1.5m with the UK and others preferring an even more cautious 2m. The guidance essentially means that the further you're apart, the safer you ought to be but it's not distance alone that matters. The second key factor is timing - how long you're close to someone.