A recent article on Jalopnik asked the question:
In the United States, the Center for Disease Control (CDC) recommends the public wear cloth face coverings in settings where physical distancing measures are hard to maintain. Back home, the Public Health Agency of Canada (PHAC) has released a statement that Canadians can use non-medical masks along with physical distancing, hand hygiene, and other measures to limit the transmission of the virus, noting that public wearing of medical masks may result in additional shortages of masks needed to protect front-line healthcare workers.
So, rather than using up the scarce and limited resources of N95 or surgical masks, Canadians are turning to home-made solutions. One option for those in the motorsports community is…their helmets.
Helmets allows the wearer to breathe through the opening at the bottom of the helmet and through vents. Even though outside air has to travel a different route, it is reaching the helmet wearer unfiltered. However, wearing a balaclava under the helmet would provide a physical barrier (similar to a non-medical mask) that blocks the path of air and droplets of those speaking moistly.
Does it make sense to wear your Arai or HJC helmet with full NOMEX balaclava to go outside?
Just stay home.