The battle against airborne droplets

Ventilation systems can help remove viruses from living spaces.

Being in a room with fresh air can reduce the risk of infection from common viruses, like influenza, by up to 70 per cent, according to recent research.

Kim Williams, market manager for SmartVent, a company specialising in ventilation systems, says there are various pieces of research which suggest ventilation has a preventive effect when it comes to the spread of viruses like influenza.

"One thing we know is the ever-present threat of airborne viruses remains," she says. "Experts believe the flu is primarily spread through droplets released when an infected person sneezes, coughs or speaks."

These droplets land in the mouths or noses of people nearby. Or a person might touch a surface contaminated with them, then touching his or her face.

"Now there's evidence showing that influenza transmission can also be airborne," says Williams. "A 2018 study published in the US found the flu virus can be shed in tiny droplets suspended in the air from the exhaled breath of infected people."

It's not yet known how far these infectious droplets travel or how long they stay in the air but airborne viruses are definitely known to linger in spaces with no fresh air, increasing the risk of people breathing in infected particles.

The risk reduces significantly by regularly ventilating enclosed spaces, with some research showing that being in a room with fresh air can reduce the risk of infection from particles by over 70 per cent, as fresh air dilutes the particles – a fact behind Britain's Department of Health and Social Care which began a public health campaign late last year based on the 70 per cent research above.

There is plenty of other evidence backing up the importance of adequate ventilation:

• Professor Joseph Allen, of Harvard University, led a research team which showed that the risk of measles transmission rates were reduced by 50 per cent when ventilation and filtration rates were increased above industry minimums and where portable air purifiers were used to supplement building systems.
• In 2008, a 20-year study by Otago University concluded in 2008 that 1600 people died every year during the four winter months, with the bulk of the deaths caused by circulatory, respiratory illnesses and infectious diseases.
• •In 2015, the Building Research Association of New Zealand (BRANZ) House Condition Survey found that about half of all houses lacked adequate insulation (47 per cent), contributing to many being damp and mouldy (49 per cent). Dampness and mould were more prevalent in rental homes, with 56 per cent showing mould – compared to 44 per cent of owner-occupied homes – and the report said there was a need for more effective ventilation.
• James Powers, a director of building science company Oculus told the Herald last year there was a lack of effective requirements for building houses in New Zealand: "It's particularly bad in New Zealand, as evidenced by our housing related health problems. Our homes are typically too cold and too damp. We don't heat and ventilate our homes effectively…because the [building] code has been below standard for some time."

Photo / Supplied.

For a long time, he said, there has been no requirement to build efficient, sealed homes that maintain internal temperature and adequately ventilate air – the essential components of a warm house with the right humidity.

Williams says research has proven that ventilation systems using outdoor air can be more effective than opening windows or doors, as long as they are limiting the recirculation of the same air.

She says they are often confused with heat pumps – ventilation systems circulate fresh air; most heat pumps do not draw air from outside, simply heating the air in a room, and are limited in their ability to dilute airborne viruses captured in a room.

"The majority of virus transmissions happen indoors. Being indoors, with no fresh air, the virus particles can remain suspended in the air for hours and build-up over time," she says. "For those among us with weaker immune systems or predispositions to respiratory conditions such as asthma, the risks are even greater.

"A lack of ventilation leads to homes that are more likely to suffer from dampness and mould issues. According to the World Health Organisation, a considerable portion of the world's 300 million cases of childhood asthma is attributable to exposure to dampness and mould. "

SmartVent has a range of ventilation solutions for homes and we encourage you to get in touch to find out which system suits your needs and lifestyle. Call us today on 0800 140 150 or email enquiry@smartvent.co.nz for advice or to arrange a home assessment by one of our friendly accredited installers.