Prior to COVID-19, we spend approximately 90% of our time outside our homes. In the time of the COVID-19, more individuals are staying home for prolonged periods, many due to the movement control order, and for some due to personal choice as a social distancing measure.
Initially, it was thought that SARS-CoV-2 – the virus that causes COVID-19 – was primarily transmitted through droplets generated when an infected person coughs or sneezes. More than thirteen months after the World Health Organisation declared the pandemic, the agency has formally recognised that SARS-CoV-2 is airborne.
How does indoor air quality affect COVID-19 transmission? The risk of getting COVID-19 is higher in crowded and inadequately ventilated spaces where infected people spend long periods of time together in close proximity. These environments are where the virus appears to spread by respiratory droplets or aerosols more efficiently, so taking precautions is even more important.
What makes indoor spaces so dangerous is that exhaled virus can accumulate and infect people who do not have direct contact with an infected person. A prime example happened earlier in the year where COVID-19 cases emerged in gyms and fitness centres around Klang Valley, despite physical distancing of attendees and capacity limits on fitness classes, forcing temporary closures on these establishments for sanitisation and quarantine for staff who came into close contact with positive cases.
Ventilation and maintaining good indoor air quality, when used along with other best practices recommended by the Ministry of Health and others, can be part of a plan to protect people indoors. The Department of Occupational Safety and Health has recently developed a ventilation and indoor air quality guide that can be used during the COVID-19 pandemic to reduce the airborne transmission of the virus. The public may consider adopting this general advice, which can be applied to all homes:
- Open windows to ventilate room spaces with clean outdoor air. Leave a small opening when air-conditioner is in operation. Opening windows remains key in curbing the spread of the virus, health expert said.
- Operate electric fans to increase air movement and enhance thermal comfort.
- To improve ventilation, operate exhaust fans wherever available.
- If operating an air-conditioning system, set the temperature between 23°C and 26°C.
- Maintain humidity between 40% and 70%.
- Ensure water seal in sanitary system is intact and rectify crack, if any.
- Create an isolation area for sick, infected, or suspected household members.
Better indoor air quality has been proven to decrease the risk of COVID-19. By increasing indoor air quality, it is also possible to minimise anybody’s risk of a slowly developing chronic respiratory illness, starting from early childhood, which in turn helps in the fight against possible future epidemics and pandemics.
Written by: Dr. Nur Nabila Binti Abd Rahim, a Doctor of Public Health student for the University of Malaya and Dr. Lim Yin Cheng, Public Health Medicine Specialist and Lecturer, Department of Social and Preventive Medicine, Faculty of Medicine, University of Malaya