Thousands of cases of COVID-19 have been reported in schools across Europe but could a DIY innovation costing just $235 help teachers and students to fight the virus in the classroom?

That's the hope in Germany, where the scientist husband of a secondary school teacher in Mainz has created and installed a ventilation system to remove COVID-19 particles from the air.

Frank Helleis, a Physicist and the inventor, created the system using materials from a local DIY store and installed it at IGS Mainz-Bretzenheim school.

The technology sucks up potentially contagious air exhaled by pupils and teachers via funnels positioned on the ceiling above each desk and then flushes it outside via pipes.

Helleis explained the purpose of his creation: "If we assume that a pupil is contagious for about two days before knowing it, they have a lot of time to infect their classmates by spreading aerosols through breathing or talking because they spend so much time in the same room."

Tests carried out by the prestigious Max Planck Institute for Chemistry, where Helleis works, have shown the system manages to remove over 90 percent of aerosols from the room, on par with the most high-tech air filtration units on the market.

The difference is that Helleis's light-weight contraption can be built from materials from the do-it-yourself store for around 200 euros ($235). 

A handful of volunteers put it together in half a day, he said, and the Max Planck Institute has shared the assembly instructions online for anyone who wants to copy the idea.

News of the success and affordability of Helleis' product has spread throughout Germany, with 3,000 schools inquiring about the invention since its installation.

Experts now expect it will be rolled out at schools across Germany upon the completion of successful trials after receiving the backing of teachers and students. 

Roland Wollowski, principal at IGS Mainz-Bretzenheim secondary school, said: "The mood in German schools is increasingly uncertain. The case numbers are rising, including at schools. 

"That's why we will be happy if we have these ventilation systems everywhere soon, then we can be much more relaxed about teaching."