Cruise ship AC systems could promote rapid coronavirus spread, prof says

WHAT: A growing number of coronavirus cases have been reported on the Diamond Princess cruise ship despite a two-week quarantine that ended Wednesday. The first deaths were reported Thursday.

According to a Purdue University air quality expert, cruise ship air conditioning systems are not designed to filter out particles as small as the coronavirus, allowing the disease to rapidly circulate to other cabins.

EXPERT: Qingyan Chen, Purdue’s James G. Dwyer Professor of Mechanical Engineering, has researched the spread of air particles in passenger vehicles and how to track them. His team developed models in the past for showing how the H1N1-A flu and other pathogens travel through aircraft cabins.

When Chen co-led the Air Transportation Center of Excellence for Airline Cabin Environment Research, his lab made discoveries about the airborne nature of SARS that could inform understanding of the coronavirus.

Chen’s lab is currently developing a ventilation system that would prevent the spread of pathogens by allowing each person to breathe in only his or her own air.

QUOTE: “It’s standard practice for the air conditioning systems of cruise ships to mix outside air with inside air to save energy. The problem is that these systems can’t filter out particles smaller than 5,000 nanometers. If the coronavirus is about the same size as SARS, which is 120 nanometers in diameter, then the air conditioning system would be carrying the virus to every cabin.

Cruise ships could minimize this problem by just using outside air and not recirculating it.”

NOT JUST CRUISE SHIPS: For aircraft, the coronavirus is more likely to spread by touch than through the air, Chen said, since the air conditioning systems of planes are capable of filtering out particles as small as viruses.

But air carrying the virus could transfer to other people sitting in the same row as an infected passenger or a neighboring row. “The further away you’re sitting from a person who is infected, the better,” Chen said.

Toilets would be the biggest hot spot for the virus on a plane.

“Stool also contains viruses. Close the lid before you flush to limit how much goes into the air. Planes should provide wet wipes with alcohol to prevent the spread of the virus through touch,” Chen said.

Writer: Kayla Wiles, 765-494-2432, wiles5@purdue.edu

Source: Qingyan Chen, 765-496-7562, yanchen@purdue.edu