WHO (WHO) points out that crowded and poor ventilation can aggravate the risk of infection with new crown . The virus spreads between people through infected respiratory particles in the form of droplets and aerosol . In poorly ventilated spaces, infected aerosols can be suspended in the air and can spread more than 1 meter away. Improving indoor ventilation can effectively reduce the risk of the virus spreading indoors.
Ventilation not only introduces fresh outdoor air into the room, but also requires the indoor air to be discharged to the room.
For better ventilation, we can open the doors and windows opposite the sides of the room to cause air convection . If air convection is not generated, place a fan in front of the open window to increase air flow and drain indoor air outside.
If the temperature outside is extremely hot or cold, you can open the window for a few minutes per hour to introduce fresh air.
"2022 Coronavirus Pneumonia Epidemic Prevention and Control Knowledge Manual" also recommends that windows should be opened for ventilation every morning, afternoon and evening, and the ventilation time should be no less than 15 minutes each time.
Someone in the community was diagnosed. Can you open the windows for ventilation?
is OK. Wang Xinyu, deputy chief physician of the Department of Infection at Huashan Hospital Affiliated to Fudan University, introduced that if outdoors, due to the effect of air flow, the high concentration of aerosols discharged by infected people can be quickly diluted by fresh air, which cannot reach the concentration of infected humans. Similarly, if the indoor aerosol containing high-concentration virus particles is blown outdoors through the window and is quickly diluted, it is unlikely to cause "cross-building" transmission.
However, Wang Xinyu also reminded that in some special circumstances, you need to pay attention to
. "Some communities have too close distances, so close that a person can climb from the window of one building to the window of another building opposite. In this case, if the windows are opened at the same time, theoretically there is a possibility that the aerosol is not fully diluted by outdoor air, thus 'crossing the building' into another building. However, as long as the air continues to circulate, the aerosol will be quickly diluted to the point where it has no infection ability."
In addition, some residential windows open facing the indoor corridor, and there may be hidden dangers of virus transmission in the same building.
However, opening windows for ventilation is always an effective measure to cut off the transmission path of air transmission. Whether it is WHO or my country's epidemic prevention policies, it has always recommended that everyone open windows and ventilate more.
Can air purifier replace ventilation?
More than one experiments point out that high-efficiency air filter (HEPA), can effectively reduce the concentration of new coronavirus in the air in a closed room, and can become a useful measure and means to assist infection control.
According to GB/T 13554-2020 "High Efficiency Air Filter", the filtration efficiency of such products without static elimination and filtration efficiency after static elimination under the rated air volume shall not be less than 99.95%, that is, the ratio of the amount of aerosol filtered by the filter element to the amount of aerosol before filtration.
WHO also pointed out that although air purifiers can reduce the possibility of virus transmission, they do not provide ventilation and cannot replace other ventilation methods. Even if such products are used, windows should still be opened for a few minutes per hour to introduce fresh air.
Express delivery and group buying have become a must for citizens' lives during the lockdown period. However, express delivery items have the risk of spreading the new coronavirus. We must pay attention to disinfection and protection, and pay attention to three key links! In this regard, the Municipal Environmental Remediation and Disinfection Working Team, the Municipal Patriotic Health Campaign Committee Office, the Municipal Disease Prevention and Control Center , and the Municipal Health Promotion Center made special reminders: 1. The regional express distribution center
do a good job in environmental disinfection in the venue every day, and strengthen the disinfection of high-frequency contact surfaces such as shelves, trolleys, and code scan guns. Maintain ventilation in the workplace and strictly implement protective measures.
Express delivery vehicles should be cleaned and disinfected every day, especially for frequent contact areas such as steering wheel, door handle, handrail, etc. You can wipe and disinfect 250mg/L chlorine dioxide or chlorine-containing disinfectant with effective chlorine of 500mg/L. After 30 minutes of action, wipe clean with clean water.
practitioners must strictly implement nucleic acid testing and antigen self-test. During the delivery process, couriers must standardize the wearing of masks and other protective supplies, and adopt contactless delivery methods to reduce direct contact with items in public places and community personnel.
After the express delivery items reach the distribution center, spray and disinfect the express delivery before sorting. All surfaces of the items must be disinfected in place. The surface of the sprayed disinfection object must be hung with beads or moist. After disinfection, place for 30 minutes before sorting. Strictly implement the "disinfection first, then distribute". Sorting personnel wear masks and gloves when sorting. 2. Community express delivery location
The community should reasonably set up centralized disinfection shelves or areas for express items, and disinfect shelves and other storage facilities. You can use 1%-3% hydrogen peroxide , 250mg/L chlorine dioxide or 500mg/L chlorine-containing disinfectant to spray and disinfect shelves and other facilities, disinfect 3-4 times a day. If there are many express delivery, the disinfection frequency can be increased.
After the goods arrive at the community, the community disinfectant should use the above-mentioned concentration of disinfectant to spray and disinfect the outer packaging of express items. Each side is sprayed, the surface is evenly and humid. After disinfection, it can be left for 30 minutes before it can be taken.
Disinfection personnel should take good personal protection and hand hygiene, and wear first-level + protective supplies, including disposable hats, KN95/N95 and above protective masks, goggles or protective face screens, isolation clothing, and gloves. Wear and remove personal protective equipment in a standard order, and dispose of removed personal protective equipment according to special garbage.
3. Personal express delivery
receives express delivery through contactless method. Try to remove the packaging outdoors, and discard the removed internal and external packaging in time. Wear a mask and gloves, and wipe and disinfect the contact table after disassembly. Avoid touching your eyes, mouth, and nose with your hands during collection and unpacking.
The outer packaging and inner packaging of items can be wiped and disinfected with disinfectant spray or disinfectant wipes. Spray and disinfect the packaging so that the packaging can be seen moist or the disinfectant is beads. After disinfection, leave it for 10-30 minutes before contacting.
Vegetables and fresh foods are not recommended to use disinfectant to spray and disinfect. You can rinse or soak or drain it with slow water flow, and wear a mask and gloves when cleaning. If you do not need it urgently, you can open the express delivery and place it in a ventilated place such as a balcony. After processing the express delivery, clean and wash your hands with "soap/hand sanitizer + running water" in time.
News Morning News Weekly APP Reporter Lu Yi Chen Liyu
