GEORGE TOWN: Health experts have called for the widespread use of carbon dioxide (CO2) monitors indoors to keep Covid-19 at bay.
This comes after reports that poor ventilation in indoor spaces is a major contributor to the spread of the virus.
They told FMT that CO2 is a potential Covid-19 carrier as people exhale carbon dioxide, which becomes contained in spaces that have inadequate ventilation.
They said CO2 monitors can indicate how well a space is ventilated.
Virologist Vinod Balasubramaniam said the breath of a Covid-19 positive person can linger in the air longer in places with poor ventilation.
“The exhaled virus can accumulate and infect people even if they do not have direct contact with an infected person,” the Monash University Malaysia senior lecturer said.
“The infection risk rises especially when there is no air change. Outdoors, even a light wind can rapidly reduce concentrations of airborne viruses.”
Vinod said the CO2 levels outdoors hover around 400ppm, while less than 800ppm of CO2 indoors is an indication of a well-ventilated space.
Indoor CO2 levels should be measured away from the windows and doors and tests should last at least an hour, he said.
He said spaces such as offices, schools or areas where people congregate should have regular breaks to allow ventilation and reduce the potential for viral exposure.
Exhaust fans in kitchens and toilets should also be cleaned, he said, to allow the optimal airing of indoor space.
Large rooms with open windows are ideal
Universiti Sains Malaysia’s (USM) virologist Kumitaa Theva Das said while CO2 levels are not a direct measure of possible exposure to the virus, CO2 monitors can be useful in cutting down the spread of Covid-19.
She said the US Centers for Disease Control and Prevention had found that the virus can be passed on through aerosolised particles, and a sneeze or exhaled breath can remain in the air for a couple of hours.
“Hence, keeping apart from one another and raising the alarm to your building managers when the air feels stale can cut down the risk of transmission.
“Viruses can be dispersed if there is proper airing. An ideal indoor space is a large room with open windows,” she said.
USM’s indoor air quality researcher Mardiana Idayu Ahmad said offices with recirculating-type air conditioners should open their windows every 30 minutes so stale air can be released and fresh air drawn in.
She said each enclosed area in an office should have its own CO2 monitor and ventilation fan or exhaust system to clear out stale air.
“To add another layer of protection, all should wear masks at all times in indoor spaces,” she said.
‘Sick building syndrome’
Universiti Tunku Abdul Rahman’s Bernard Saw said office managers can start by measuring CO2 levels with all staff present, to set a baseline and decide if there is carbon dioxide buildup.
Saw, an expert in thermal management, said while air filters can help promote cleaner air, they do not provide fresh air, which is key to ensuring ventilation.
One way to solve this problem is to install a fresh air supply device, which can be costly, or to use ventilation fans or open the windows for fresh air to come in.
“If you have enough fresh air supply, you can dilute the pollutants present in the building to minimum levels,” he said.
Saw said that besides the risk of Covid-19 infection, persons in poorly ventilated places may suffer from “sick building syndrome”, or SBS, which causes them to experience a multitude of illnesses due to poor air quality.
The sicknesses range from headache to eye, nose or throat irritation and nausea, while some complain about difficulty in concentrating and fatigue.
The Department of Occupational Safety and Health (DOSH) has set standards on indoor air quality at workplaces, with ventilation levels not exceeding CO2 readings of 1,000ppm at any one time. - FMT
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