What are the transmission routes of novel coronavirus pneumonia? Is central air conditioning at risk of spreading COVID-19

At the beginning of the outbreak of the epidemic, someone proposed that the central air conditioner had the risk of spreading viruses. In fact, this statement is not completely correct. The air conditioning pipes of the central air conditioner are connected. If there is COVID-19 in one room, it is very likely that it will spread to other rooms through the pipes connected by the central air conditioner, accelerating the spread of the virus. But in fact, there are many types of central air conditioning, and the possibility of transmission mainly depends on the return air path of the central air conditioning. For example, the central air conditioning of duct type units needs to be strictly controlled in use. This type of central air conditioning has indoor units that suck in air through the return air outlet arranged on the ceiling, exchange heat, and send it into the ducts (ducts) installed in the ceiling of each room. The air is then delivered to each room through the diffuser on the outlet, and the return air is centrally heat exchanged and then dispersed, which is not conducive to virus control. This type of central air conditioning is generally used in large public places such as shopping malls and airports. The common modes of transmission of coronavirus include: 1. airborne transmission, such as coughing and sneezing. 2. Contact transmission, such as shaking hands, involves touching objects carrying the virus and then touching the mouth, nose, or eyes with one's hand. Due to the high incidence of respiratory infectious diseases and viral pneumonia in winter and spring, attention should be paid to keeping warm, ensuring indoor ventilation, maintaining personal hygiene, strengthening physical exercise, avoiding crowded places, closely monitoring for symptoms such as fever and cough, and seeking medical attention promptly when such symptoms occur.