As South Africa tries to get its economy back on track following the easing of lockdowns and travel restrictions imposed by the government to curb the spread of the coronavirus disease, the country’s Transport Minister as assured nationals of their safety while using public transportation.
Even though the country has moved down to lockdown Level 2, cases continue to rise and the death toll already stands at over 12 000. This has left South Africans concerned over their well-being, especially since things are returning to a more normal state.
Fikile Mbalula has been hard at work reassuring South Africans – who rely heavily on public transport – that their safety is the government’s main priority. He addressed the media on everything from safety in taxis and buses to the reopening of the aviation industry. When the country moved to lockdown Level 3, flying inter-provincially for the purposes of work was allowed.
The minister of transport revealed in late June that domestic flights could resume at “100% capacity”. Mbalula talked about the safety measures put in place to help stop the spread of Covid-19 on planes. He made a blunder that went viral while talking about the High Efficiency Particulate Air (HEPA) filters.
This brings us to the question: can the HEPA filters really “eat” all the viruses and bacteria in the cabin?
HEPA filters are being used to clean the air in planes to help passengers stay safe against Covid-19.
What are HEPA filters and how do they work? The filters work by cleaning the air in an airplane by removing “virtually all viruses and bacteria”, the International Air Transport Association (IATA) said. Air passes through the filter and is mixed with air from outside the plane before it is recirculated back into the cabin.
This ensures that the air inside the cabin is replaced every two to three minutes and it consists of 50% fresh air and 50% filtered air. “Even the most difficult particles in the range of 0.1 to 0.3 micron are filtered out with an efficiency level of 99.995%.” The Covid-19 particles are about 0.1 microns in diameter, which means that the HEPA filters should be able to remove the particles that are in the air. So, does that mean the HEPA filters ‘eat’ all viruses? Well the short answer is no.
In order for the filters to do its job to get rid of all viruses, the particles need to stay in the air. Prof Shaheen Mehtar, an infection prevention and control specialist based at Stellenbosch University, told Africa Check that HEPA filters do a good job filtering air, but they don’t capture “any form of virus” in a plane.
Prof Ana María Rule, an assistant professor at the Johns Hopkins Particulate Matter Research Centre in Baltimore in the US, said: “When we talk about how human beings generate viruses, we have to think that there’s a huge range of particle sizes.”
To make it simple, particles that are created when people cough, breathe or speak are too large in diameter to stay in the air. Air-handling systems in planes only captures smaller particles that are carried in the air.
The larger particles, such as in saliva, are too heavy to stay in the air and would rather fall and land on surfaces or passengers. This could lead to people getting infected by either touching the surfaces and then their faces or if the large particles land on a person. Rule said that although air-handling systems definitely do help, they do not completely prevent infections from spreading on planes.
Source: briefly.co.za
