Can AC Spread Corona Virus?

If coronavirus can suspend in air, then it could be spread with air conditioning system? This question become popular when 10 persons got infected from Covid-19 after a lunch in a same restaurant having no windows.

CDC (Center for Disease Control and Prevention) publish a research report in which 10 persons from different families (Say A , B and C) were studied. They had eaten a lunch under the same roof of 5 story air-conditioned restaurant in Guangzhou, China.

On 23rd January, One of the family (A) traveled from Wuhan, from where this outbreak start.  Patient one from family A () had a lunch with family in a restaurant in which family B and C were also present. Distance between these families was more than one meter.

Only patient one from family A was infected at this time that showed their symptoms after a day.  By 5th February, 9 others (4 from family A, 3 from family B and 2 from family C) members show positive for COVID-19.

Apparently Patient A was the source of exposure for all other effected people of family B and C. Researchers stated that virus transmitted to only one person of family B and C from Patient one and further infection was due to their own physical contact within-family. No other person in the restaurant found positive as total 93 people were there in this time.

Findings

Findings: The research report said: "We conclude that in this outbreak, droplet transmission was prompted by air-conditioned ventilation. The key factor for infection was the direction of the airflow."

They believe that small sized virus droplets which can move more than one meter do not cause this. This is because no other person in the restaurant was infected as there were 93 people total.

​Read also: ​Why AC Cleaning is Important in UAE​

As for as large droplets are concern, they cannot move more than one meter. Strong airflow could have helped to propagate the droplets to the tables where families B and C dined.​

Recommendation

Recommendation:  They recommend “strengthening temperature-monitoring surveillance, increasing the distance between tables, and improving ventilation.”  These Chinese researchers emphasise on open ventilation. A building should not circulate its own air. Windows must be open and AC should bring air from outside.