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COMPARED TO SURFACE DISINFECTION, IT IS MUCH HARDER TO REMOVE SARS-COV-2
VIRUS IN THE AIRSTREAM THROUGH FILTRATION, DUE TO THE SIZE OF THE VIRUS. |
HEPA or High Efficiency Filtration is NOT the
Complete Answer
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| HEPA filter has very limited airflow capacity, and it can not be used for the filtration of the main airstream for any regular forced air systems serving buildings due to its high resistance to the airflow. Regular MERV 13 & pleated filter has very limited capacity to intercept SARS-Cov-2 with a size range of 60 nm ~ 140 nm (0.06 ~ 0.14 microns). The regular filter may intercept large droplets containing the virus, but the virus will eventually break-off and escape the filter as RH humidity drops and temperature rises near the heating equipment. |
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| Warning |
Ventilation
Airflow Rate is limited by HVAC Systems' Equipment Capacity
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| The
FDA does NOT authorize the use of Ozone " in any medical condition for
which there is no proof of safety and effectiveness". In any cases,
the business reopening guidelines and restrictions from local authority,
health departments must be followed. |
"Increasing outdoor air Ventilation, especially the replacement ventilation", is the most effective means to control indoor air quality. However, outdoor air ventilation comes with high energy costs, and almost any HVAC system will not have sufficient heating / cooling capacity for the increased outdoor air ventilation in both Summer and Winter seasons. We only have limited HVAC systems that are designed to handle 100% outdoor air, such as HVAC systems serving O/R rooms in the hospitals. As weather gets cold, the HVAC system capacity will soon be maxed out if outdoor airflow rate is increased. Furthermore, the relative humidity will drop significantly when the O/A flow rate is increased for HVAC systems serving buildings in cold climate zones. The lower RH level in the building, the easier the virus will spread. |
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| Controlled
Ozone (O3) is the key to disinfect indoor space, and turning indoor space
to outdoor space while maintaining comfortable Temperature, RH value in
the occupied indoor space. |
WH
Engineering has developed an unique approach to disinfect whole indoor space
with ultraviolet (UV) light and controlled ozone (O3) content in the air
for specific duration in specific time. It provides proofing result by comparing
the Ct value (before and after of the RT-PCR test) for suspended airborne
virus content in the indoor space. |
| Reminder |
UV
light and controlled Ozone treatment for the building must be carried out
by the professionals with extensive knowledge about building HVAC system,
and Indoor air Quality, and the nature of the infectious coronavirus disease
_Covid-19. The treatment process may involve in air system and air flow
control, building automation system override, time frame planning, airflow
purging after the Ozone (O3) treatment...etc. The remaining O3 content in
the air must drop to the safe level prior to the space occupancy. |
| UV
light & controlled ozone content solutions must NOT replacement other
required pandemic control measures: such as physical distancing, face masks
protection, hands washing, occupancy limit...etc. |
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WH Engineering will monitor the Ozone (O3) content in the whole process very closely, and ensure Ozone (O3) guidelines, standards from following organizations are strictly followed: EPA, WHO, NOISH, ASHRAE, Health Canada and Ontario's Ambient Air Quality Criteria (AAQC)... As a matter of fact: The actual outdoor air O3 content is always higher than the indoor ozone content in the guidelines, especially the eight hour exposure guidelines.
O3 is the most effective ingredient to inactivate viruses in the air and on surfaces (maybe on the surface of human lungs as well). Outdoor O3 is produced by the sunlight, when the Vacuum UV (100~200 nm wavelength) light knocks off the single O from O2, NOx, VoC etc... NOx and VoC contribute smog, but not O3. O3 is the byproduct from the process when sunlight breaks down the NOx & VoC etc... |
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Important
FACT |
| O3
in the air will oxidize lots of materials, including virus it collides with.
It will turn into O2 and dissipate within 1/2 hour to maximum 4 hours. Excessive
ground-level O3 in the air will cause chest pain, throat irritation &
air way inflammation, bronchitis, emphysema etc... |
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Affiliate
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