The air that we breathe: Indoor air quality crucial in limiting the spread of Covid-19

23 May 2021

A well-ventilated space is not created simply by opening a window. In many places where people gather (such as large open-plan offices or restaurants), there are no windows, or people are understandably reluctant to keep windows open when the weather is cold or rainy.

Robert Randolph is a registered occupational hygienist and a member of the panel of experts of the GreenFlag Association. He is also the CEO of environmental health company Apex Environmental. The GreenFlag Association is an international organisation aimed at reducing the transmission of Covid-19 and other airborne pathogens in closed-air public spaces.

For the past year, we have been following strict protocols to prevent the spread of Covid-19, but we have arguably been missing out on one of the most important ways to curb the disease – properly ventilated spaces. And what does that even mean?

Yes, it is important to wash your hands, wear your mask and practise physical distancing. However, we need to urgently apply a fourth protocol – ensuring we have fresh air, particularly in public spaces.

The World Health Organization (WHO) recently changed its stance on the transmission of Covid-19, saying there is now evidence that the disease is airborne. As such, Covid is not only spread between people through droplets, but can be spread over longer distances as airborne particles that can float in the air and survive for hours – especially in poorly ventilated spaces. The more virus-laden particles you breathe in, the higher the risk of contracting Covid.

The rapid transmission and higher mortality rates associated with Covid-19 have heightened public awareness of the need to take preventative measures. But there has been a lot of confusing debate about how Covid-19 is transmitted, partly as a result of vacillation by the WHO. On 30 April, the WHO finally amended its Q&As to say that:

“Current evidence suggests that the virus spreads mainly between people who are in close contact with each other, typically within 1 metre [short-range]… The virus can also spread in poorly ventilated and/or crowded indoor settings, where people tend to spend longer periods of time. This is because aerosols remain suspended in the air or travel farther than 1 metre [long-range].”

South Africa is still extremely vulnerable to the spread of Covid and, especially going into winter, there is still a threat of a possible so-called third wave. Along with the slow and erratic nature of the national vaccine rollout, and possible Covid-19 mutations raising fresh fears, it is crucial that we do our utmost to mitigate the predicted third wave and protect ourselves, our communities and livelihoods.

It is not always possible to self-isolate, and with the economy gathering a bit of speed, people are becoming more active, returning to work and attending social gatherings. The highest risk areas for airborne transmission are public transport, schools, shopping malls, restaurants and bars, hotels, places of worship, night clubs and hair/beauty salons. That lesson came home strongly last year, when the Matric Rage events that took place in Ballito, Plettenberg Bay, Johannesburg and Jeffreys Bay in November and early December were identified as “superspreader” events.

This is where ventilation becomes critical. With something as simple as proper ventilation in public spaces, we can drastically decrease the likelihood of spreading the disease.

According to the National Institute for Communicable Diseases (NICD), 848 people tested positive for Covid-19 after the Ballito festival.

“Factors such as mass gathering without using appropriate personal protective equipment, crowded spaces, poor hygiene and ventilation, and increased social inhibition due to alcohol consumption, may have produced a conducive environment for transmission of SARS-CoV-2 during these gatherings,” the NICD said.

A well-ventilated space is not created simply by opening a window. In many places where people gather, there are no windows (such as large open plan offices or restaurants), or people are understandably reluctant to keep windows open when the weather is cold or rainy.

Indoor air quality (IAQ) risk assessments provide us with a tool to measure and assess the ventilation risk that a public space presents when it comes to the spread of an airborne disease such as Covid. An IAQ assessment need not be an enormously expensive exercise. It can be done simply and cost-effectively by assessing airflow, occupancy rates and the measurement of CO2 levels in the space.

As humans exhale CO2, it is widely used as an indicator gas for establishing risks for the spreading of airborne diseases such as Covid. The more people who exhale CO2 in a closed space, the more the gas accumulates and concentrates. Without proper ventilation, the space would soon be saturated with CO2, which is then rebreathed by the occupants. The airborne concentration of Covid particles works on exactly the same principle – which is why ventilation in crowded spaces is so crucial.

South Africa should adopt a broad approach to addressing air quality standards. This must include changes in public messaging to raise awareness of the need for good ventilation, what that means and why we need it; updating regulations, directives and guidelines for the public and private sector so that employers and employees understand the risks of aerosol transmission and the actions they can take to prevent it; and develop IAQ standards for indoor public spaces. IAQ standards should be clear, simple and easy to implement.

Just because there are regulatory requirements for air quality assessments and remedial action does not, unfortunately, ensure that they are going to be followed. How is an ordinary citizen to know that a public space meets certain air quality standards?

In the same way that Blue Flag certification indicates that a beach meets specific standards on cleanliness, safety and accessibility, certification by the GreenFlag Association provides assurance to the public and employees that a venue is safe to visit because it complies with not only existing Covid protocols but also critical ventilation standards: the provision of clean fresh replacement air that prevents an accumulation of the virus.

It is now time to take air quality more seriously, not just through the pandemic but in the longer term. The provision of fresh clean air is a surprisingly effective preventative measure for the spread of many airborne diseases. What the pandemic has taught us is that improving indoor air quality as well as identifying poor ventilation hot spots, will also help mitigate the spread of other endemic airborne diseases, such as tuberculosis, colds and seasonal influenza. This can only result in significant health and economic benefits.

The message we should be getting out is, yes, wash your hands, wear a mask, practise physical distancing, but more importantly for public spaces like public transport, schools, restaurants, places of worship and nightclubs – ensure your indoor space is well-ventilated with fresh clean air either naturally or mechanically, to prevent the potential accumulation of the virus in the air. DM

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