• ACs can reduce the risk of spreading disease by increasing air exchange (introducing fresh air
from outside the building).
• The AC system can be a SARS-CoV-2 transmission medium in buildings if it only uses the air
recirculation method.
• Air flow from the air conditioner can expand/increase the range of the droplet (especially the
droplet nuclei) from the infected person to its surroundings in the room.
3.5 Strategies for selection and operation of Air Conditioning (AC) during the SARS-CoV-2
pandemic period
The selection of the right system, operation and AC equipment is very important in reducing the risk
of SARS-CoV-2 transmission. Based on the following research, several ways that can be taken to
reduce these risks, namely the use of proper filtration for air conditioners. SARS-CoV-2 has a size
spectrum of 0.25–0.5 µm and thus requires high efficiency filtration to prevent the transmission
of SARS-CoV-2 pathogens. Health facilities (for example hospitals) to prevent airborne disease
transmission using MERV-13 or higher and combined with HEPA filters to filter out very small
pathogens in the air. Setting an air-conditioning system that can maintain room humidity (RH)
between 40% and 60% can limit the spread and survival of SARS-CoV-2. Utilizing an air handling
unit (AHU) in an AC system to increase room air exchange (taking clean air from outside the
building) can help melt contaminants (virus particles) from the air. Based on the results of studies
of irradiation for 10 minutes using UV-C light can deactivate (99.999%) SARS-CoV and MERSCoV, so that the irradiation method using UV germicidal (UVGI) can be applied to the AC system.
This irradiation is carried out on a mechanical ventilation duct (ducting) to avoid direct contact
with humans (Dietz et al. 2020). The use of a timer or CO2 detector intended to save energy in
an AC system must be avoided because it will reduce the level of air exchange in the room. In
addition, the regulation of the air flow direction from the AC outlet must be sought not to lead
directly to humans/users of the room, especially those who have long activities in the room and
tend to be in a fixed position (not moving much) to prevent the transmission of pathogens directly
and continuously through the air flow (European Centre for Disease Prevention and Control 2020).
Efforts to reduce the risk of deployment through the selection of systems, operations, and AC
equipment also have several consequences, such as increased energy use to increase air exchange
through AHU which has an impact on inflated operational costs, increased air exchange (entering
air from outside into the room) also impacts filtration requiring maintenance more often, not all
AC systems can increase humidity in the room so to realize it requires certain AC equipment and
special care in the room to prevent the appearance of mold and mildew due to increased humidity
(Dietz et al. 2020).
4 CONCLUSION
Based on the discussion from various literature above, it can be concluded that the ventilation and
AC system has a very large influence both on transmission and decreasing the risk of SARS-CoV-2
transmission. Weaknesses in the ventilation and AC systems if not addressed can be a driver of
rapid increase in transmission of SARS-CoV-2. This can happen because most of modern human
life is spent in buildings and it is certain that it will always come into contact with ventilation and
AC which are part of the indoor environment conditioning system. This is exacerbated by the many
conditions of modern buildings that do not have good ventilation.
However, efforts to reduce the risk of SARS-CoV-2 transmission through systems, operation,
and maintenance of ventilation and air conditioning also have significant consequences in the
form of planning costs, supply of equipment, operation, and maintenance, and require intensive
maintenance on a regular basis. In addition, professional staff are needed to operate the systems
and equipment and to socialize them well to the building users. Not all building owners and
operators/managers have the financial ability to meet these standards, so careful analysis and
117
from outside the building).
• The AC system can be a SARS-CoV-2 transmission medium in buildings if it only uses the air
recirculation method.
• Air flow from the air conditioner can expand/increase the range of the droplet (especially the
droplet nuclei) from the infected person to its surroundings in the room.
3.5 Strategies for selection and operation of Air Conditioning (AC) during the SARS-CoV-2
pandemic period
The selection of the right system, operation and AC equipment is very important in reducing the risk
of SARS-CoV-2 transmission. Based on the following research, several ways that can be taken to
reduce these risks, namely the use of proper filtration for air conditioners. SARS-CoV-2 has a size
spectrum of 0.25–0.5 µm and thus requires high efficiency filtration to prevent the transmission
of SARS-CoV-2 pathogens. Health facilities (for example hospitals) to prevent airborne disease
transmission using MERV-13 or higher and combined with HEPA filters to filter out very small
pathogens in the air. Setting an air-conditioning system that can maintain room humidity (RH)
between 40% and 60% can limit the spread and survival of SARS-CoV-2. Utilizing an air handling
unit (AHU) in an AC system to increase room air exchange (taking clean air from outside the
building) can help melt contaminants (virus particles) from the air. Based on the results of studies
of irradiation for 10 minutes using UV-C light can deactivate (99.999%) SARS-CoV and MERSCoV, so that the irradiation method using UV germicidal (UVGI) can be applied to the AC system.
This irradiation is carried out on a mechanical ventilation duct (ducting) to avoid direct contact
with humans (Dietz et al. 2020). The use of a timer or CO2 detector intended to save energy in
an AC system must be avoided because it will reduce the level of air exchange in the room. In
addition, the regulation of the air flow direction from the AC outlet must be sought not to lead
directly to humans/users of the room, especially those who have long activities in the room and
tend to be in a fixed position (not moving much) to prevent the transmission of pathogens directly
and continuously through the air flow (European Centre for Disease Prevention and Control 2020).
Efforts to reduce the risk of deployment through the selection of systems, operations, and AC
equipment also have several consequences, such as increased energy use to increase air exchange
through AHU which has an impact on inflated operational costs, increased air exchange (entering
air from outside into the room) also impacts filtration requiring maintenance more often, not all
AC systems can increase humidity in the room so to realize it requires certain AC equipment and
special care in the room to prevent the appearance of mold and mildew due to increased humidity
(Dietz et al. 2020).
4 CONCLUSION
Based on the discussion from various literature above, it can be concluded that the ventilation and
AC system has a very large influence both on transmission and decreasing the risk of SARS-CoV-2
transmission. Weaknesses in the ventilation and AC systems if not addressed can be a driver of
rapid increase in transmission of SARS-CoV-2. This can happen because most of modern human
life is spent in buildings and it is certain that it will always come into contact with ventilation and
AC which are part of the indoor environment conditioning system. This is exacerbated by the many
conditions of modern buildings that do not have good ventilation.
However, efforts to reduce the risk of SARS-CoV-2 transmission through systems, operation,
and maintenance of ventilation and air conditioning also have significant consequences in the
form of planning costs, supply of equipment, operation, and maintenance, and require intensive
maintenance on a regular basis. In addition, professional staff are needed to operate the systems
and equipment and to socialize them well to the building users. Not all building owners and
operators/managers have the financial ability to meet these standards, so careful analysis and
117