[ad_1]
By first heat of the year and the high temperatures have already made their presence felt in our country, air conditioning returns as a necessary “accessory” for the next 24 hours for all those who cannot or do not want to go on one of the 515 organized beaches that open on weekends.
Experts insist that Adequate ventilation and fresh air renewal with fresh air is a key measure to reduce the transmission of diseases such as crown It is transmitted from person to person with droplets through the respiratory system, but this is more difficult on days with high fever and relative apnea such as those that follow.
Professors from the National and Kapodistrian University of Athens, Vasiliki Benetou (Medicine School), Dimitrios Paraskevi (Medicine School), Nikos Thomaidis (Chemistry Department), Michalis Vrachopoulos (General department) and Thanos Dimopoulos (Rector of EKPA) presents the latest data that registers the main risks of misuse of air conditioners, but also provides tips to avoid problems.
The role of droplets.
THE transmission risk through the air is higher when infectious microorganisms are transmitted through small drops (diameter ≤5 μm) compared to transmission through large droplets (diameter> 5μm). This is because the small droplets remain in the air for a long time and can be transported long distances, while the large droplets fall quickly and within a distance of 1 to 2 meters around the infected person.
Based on what we know to date, or SARS-CoV-2 virus transmitted mainly through large drops. Given this, the distance of 1.5-2 meters to be observed between individuals. In special cases, the virus can be transmitted through small drops, as is usually the case with special manipulations (eg suction, intubation) in health centers. However, it is observed that the ways in which the virus is transmitted are constantly investigated and that transmission by air (that is, through small drops) and, in other cases, cannot be completely ruled out.
A study aimed at detecting and calculating the crown’s survival time in air showed that the virus survives for up to 3 hours. However, this study should be interpreted with caution, as it was based on the artificial creation of an aerosol solution through a high-powered machine (three-jet collision nebulizer) under experimental conditions that do not necessarily reflect the actual conditions in a clinical setting.
Other studies of symptomatic treatment areas with COVID-19 patients, did not detect the RNA of the virus in the air. It should be noted that the isolation of virus RNA from air samples using the PCR method does not necessarily mean that the virus is contagious.
Study in an air-conditioned restaurant in China It concluded that transmission of virus droplets between co-conspirators by an infected person was facilitated by the direction of the air conditioning flow. The researchers suggested increasing the distance between the tables and improving the ventilation system.
The mechanisms that can transmit the virus.
Compared to The potential risk of transmission Crown SARS-CoV-2 through air conditioners (via cooling or heating) and of building ventilation systems, it is likely to occur with the following mechanisms:
(a) with the mechanical transfer of infected droplets at greater distances than expected (i.e. beyond 1.5-2 meters) due to air flows that air conditioning can cause in rooms,
(yes) with the recirculation of polluted indoor air through the air conditioner, provided that this air is not renewed,
(C) transporting the droplets through the vents of the ventilation systems and
(re) by the return of air from the exhaust ducts of the indoor air, to the fresh air ducts, to the ventilation systems (if their outlets are close to each other or through intermediate leaks).
The six basic tips.
Based on available data, basic recommendations regarding ventilation and use of ventilation and air conditioning systems in public buildings (these recommendations do not refer to health service structures) to prevent spread of crown, are summarized below:
one) Ensure natural ventilation of indoor air with fresh outdoor air as often as possible.
2. All central air conditioners that use recirculating air should be adjusted to increase the rate of fresh outdoor air supply (as much as possible, ideally 100%). Air recirculation without external supply should be avoided, as it may increase the risk of transmitting the virus.
Additionally, it is recommended that these units operate continuously 24 hours a day, 7 days a week (24/7) even when the power supply is not working. Care must be taken to ensure that the exhaust air outlets are as far as possible from the fresh air inlet points.
3) Increase ventilation time in buildings with mechanical ventilation. Continuous operation on nights, holidays and weekends is recommended (at lower speeds, however). The ventilation speed should return to normal 2 hours before the arrival of the personnel and decrease 2 hours after the departure. The extended operating time of the ventilator is intended to eliminate possible infectious drops from both the air and the surfaces.
4) Changing the temperature and relative humidity settings is not recommended. From what we know to date, the virus appears to be quite resistant to human-acceptable temperatures and relative humidity in living spaces.
5 5. Air conditioning units, fan coil type (FCU) or bilateral type (divided units), when possible, do not work. When not possible, operate continuously 24 hours a day, 7 days a week, while providing natural ventilation. The purpose of this recommendation is to avoid the recurrence of viruses in the event of interruption and restart of unit operation, as well as the adequate renewal of indoor air with fresh air.
6 6. Proper installation, regular maintenance, and refurbishment of air conditioning filters are important, according to the manufacturer and the proper maintenance schedule. However, greater operation of air conditioners under current conditions may require more frequent maintenance. Regular maintenance, cleaning and replacement of filters must be carried out by qualified personnel who take the necessary protective measures, including the protection of the respiratory system with a mask.
The relevant additional measures recommended in the context of broader health protection are:
-To ensure adequate ventilation in toilets, in which when there is ventilation it is recommended to operate continuously, while when there is no continuous natural ventilation with an open window.
-Where possible and the sanitary conditions of the facilities allow it, the toilet lid should be closed when the cistern is used. This practice is preventive and aims to limit the possible transmission of the virus through the creation of an aerosol at the time of evacuation from the toilet (since the virus has been isolated in the faeces of patients in an individual investigation).
The teachers who summarized the data point out that:
A) The above recommendations do not apply to health service structures (such as hospitals, health centers) but to public buildings in which people with COVID-19 are considered to be occasionally found (unlike care facilities medical).
B) The above recommendations seek to cover all possible possibilities coronavirus transmission even the possibility of its air transmission (although this has not been documented).
C) The above recommendations to be effective should be combined with maintaining the necessary distances between people in the workplace, washing hands regularly with soap and water or antiseptic, when necessary (to avoid transmission by contact with infected surfaces. and objects) and compliance with all instructions of your personal precaution EODY and the Ministry of Health.
D) Some of the recommendations refer only to the period of the pandemic, since the energy and financial costs must be taken into account, as well as the burden on the environment due to the change in the normal operation of the machines.
E) The infrastructure and needs of each area, in terms of ventilation and air conditioning systems, differ and must be evaluated by professionals and specialized technical services.
F) The risk of transmitting the virus through air conditioners is considered much lower in homes than in public places, as coordinated or frequent visits by family members are generally not expected (except for the presence of a sick person). with COVID-19).
G) It is important at all times:
(1) Ensure adequate ventilation of the interior with fresh air.
(2) Avoid congestion in closed spaces without adequate ventilation.
(3) The correct and regular maintenance of air conditioning machines to avoid their conversion into foci of growth and success of pathogenic microorganisms (for example, bacteria, fungi).
The Ministry of Health circular (D1 (d) / GP house 26635, 04-23-2020) and its text give recommendations for taking measures to guarantee public health when air conditioning units are used and more technical details. REHVA (Federation of European Heating, Ventilation and Air Conditioning Associations) (also translated into Greek).
News today:
Tourism: the “gray areas” of the EU directives: with which countries does Greece sign an agreement?
How Zuckerberg “ate” Instagram and tortured its inventor
The prosecutor surprised Greece in the Topaloudi trial: “Eleni went to a wild beast …”
[ad_2]
