I think we have to live with some germs & risk in our lives, holiday.
The air treatment systems are too expensive & not cost-effective.
That last link (July 2021) is still about plans not money already spent and causing benefits. Does that mean Germany hasn't spent any money on air treatment systems in schools?
I now understand that when people say "ventilation" they don't mean ventilation; they mean air treatment.
Airplanes have excellent air treatment and ventilation. Off top of my head, jumbo planes in flight replace 1/3 of the internal air every hour with external air. Their HEPA filters filter through 99.x% of all air circulating every 6 minutes.
My guess is that it would cost £1-£2 bln to achieve similar (to jumbo plane) HEPA air filtering in English schools (alone) over next 10 yrs. That could be paid for with £200-£300 extra on each household's annual council tax.
Kids spend ~33% of their waking hours (annually) indoors in school. ~50% of their awake time in private spaces, < 1hour/day outdoors. Is £1 bln a good way to spend the money?
Imagine that, To roll out the systems quickly, we hand each school immediately £2k/classroom. The prices for equipment & engineers (better systems) would skyrocket for months; there aren't enough engineers to do fancy systems in near future. The budget wouldn't stretch. if the money was given to all HTs tomorrow, My guess is we'd reach June 2022 before most schools in England had an air treatment system in operation, and that would mostly just be little portable units sucking electricity all day.
Would £1bln be a good use of the money over this period?
Do we no longer care about climate change?