Should you humidify the air to fight COVID-19? Studies split on effects of humid air

Posted at 5:22 PM, Nov 13, 2020

Health officials agree coronavirus cases are going to increase this winter as Americans head indoors to stay warm and closed windows will lead to less ventilation.

But what about the dry air inside and outside this time of year, could a humidifier help slow the spread of coronavirus? That is still being debated.

A study releasedthis month seems to suggest increasing humidity plays a role in decreasing cases of coronavirus. The study, which has not been peer-reviewed yet, was shared on medRxiv.

This study was based on the premise that previous studies have shown that falling humidity is tied to increased transmission rates of other respiratory diseases, like the flu. Researchers looked at more than 3,000 counties around the country and their humidity levels between March and September 2020.

The team says they found increasing humidity levels had a negative impact on new cases of COVID-19 in most regions. In two of the regions that showed the highest effect, a 1 g/m3 increase in absolute humidity resulted in a 0.21 and 0.15 decrease in COVID-19 cases.

However, there are also studies that show the humidity level had little to no effect on the spread of COVID-19.

A study released in early November found the weather had “virtually no impact” on the spread. Instead, they said human behavior changes during weather fluctuations, outside during warmer weather and heading indoor during cold weather, had a large impact.

What health and science experts seem to agree on is that the air does get drier in the winter from both the cold air outside and heated air inside. And that without proper ventilation, any coronavirus droplets in a space could linger longer and become more concentrated.

This dry air can also cause nasal passages to dry out, which means noses could have less protective mucus.

Some doctors have said whether or not the science completely proves humid air can help slow the spread of coronavirus, having more humidity in the air can make this winter more comfortable and noses more able to protect against all virus.