Healthcare Scientists recommend at least 40% humidity in public buildings to curb COVID-19 spread Updated : August 21, 2020 12:40 PM IST The scientists said tiny drops of five micrometres in diameter, such as those produced when speaking, can float in the air for up to nine minutes. At a higher humidity, the scientists said droplets grow faster, fall to the ground earlier, and can be inhaled less by healthy people. Subscribe to Moneycontrol PRO at just Rs.33/- per month for the first year. Use code SUPERPRO. Limited period offer. Available on Web and Android.