Hepa filters being examined as weapon against school Covid transmission

Schools are considering the use of Hepa filters in the battle against Covid-19 transmission amid falling temperatures.

As the winter sets in, schools are wondering whether high-efficiency particulate air (Hepa) filters can help them to battle Covid-19 transmission amid falling temperatures.

“We’ve been very clear that we want our schools open, and we want them to be safe,” said Pairic Clerkin, the chief executive of the Irish Primary Principals Network (IPPN).

“The message has been clear that to keep them as safe as possible, air ventilation is critically important. 

"Managing Covid is very challenging for school principals and deputy principals. I think every support that they can be given by public health will really help school communities.” 

This includes a review and reintroduction of contact tracing in primary schools. Hepa filters are another measure that would help to improve air quality in classrooms, he added. 

“Quite a number of our school buildings are old, many of our classrooms are quite small. That is going to pose a challenge in relation to ventilation. In those situations, we feel that it does need to be looked at. 

If there isn’t proper ventilation, then we do need air filtration systems." 

In March, the Government’s expert group on ventilation recommended that stand-alone Hepa filter devices may be useful in reducing airborne transmission in spaces with insufficient ventilation. 

John Wenger of University College Cork, who chaired the group, said it recommended that risk assessments of all classrooms be carried out during the spring and summer. 

“Not enough was done and we’re now paying the price for that," said Prof Wenger. 

The Department of Education did take on the group's advice regarding the introduction of carbon dioxide alarms, and it does recommend the use of Hepa filters in poorly ventilated areas, he added. The filters are a "drop-in" solution that filters the airborne particles from the air.

Not every classroom needs a Hepa filter, but any barriers to accessing or applying for the devices should be removed for schools that need them, according to Prof Wenger. 

The advice around the world is that in poorly ventilated areas where you can’t immediately improve ventilation, Hepa filters provide a good way of cleaning the air.” 

Orla Hegarty, assistant professor at the University College Dublin School of Architecture, said some schools will be at a higher risk and should be prioritised for Hepa filters if they are experiencing issues with ventilation. 

These include “urban schools where you have communities that expanded very quickly, kids in full-capacity classrooms. Often these are in areas where children are living in smaller homes, which are more likely to be crowded and multi-generational homes. They are also more likely to be homes where parents are more likely to be in frontline jobs, or using public transport,” she said.

A spokesman for the Department of Education said air cleaners may be considered as an additional measure for persistent poor ventilation.

"Schools that identify inadequate ventilation in a room can utilise their minor work grant or apply for emergency works grant assistance to address ventilation enhancements on a permanent basis."