Can COVID-19 be spread by suspended aerosols? How safe is central air?
A report published in the CDC journal Emerging Infectious Diseases details how coronavirus was spread in a restaurant from one infected person to nine other people. A detailed investigation concluded that the virus was most likely spread to distant tables by the flow of air from the air conditioner.
When an infected person coughs, sneezes or even talks loudly -- especially without a mask -- a fine mist of particles is expelled into the air. This aerosol can carry potentially infectious particles farther than the recommended six feet of physical distance. One important concern is that air conditioning systems could either blow the aerosol more quickly from an infected person to nearby people or by recirculating the air, could spread virus even farther.
The concern over recirculated central air hasn’t been proven yet, but there are a number of ways the effect could be limited. High efficiency HEPA filtration systems would trap infectious particles in the air stream, specific wavelengths of ultraviolet lights embedded in the duct work or near air registers could kill virus, and finally existing systems could be redesigned to bring in fresh uncirculated outdoor air to dilute any infectious particles in the air.
Whether it’s summer or winter -- all businesses and schools should begin to consider how they can efficiently improve indoor air quality.