First thoughts on the dangerous UK 245nm scale biological defence hack .... in terms of (just) air cleaning ... basically something like a tiny growbox/grow-tent set up should work;

- no light egress (bend intakes/outtakes 2 remove light)
- air throughput
- UV light (only) inside

= works for me ... investigating

e.g. buy or make similar to;

https://www.1-hydroponics.co.uk/product/isearch&search=30x30x60cm&category_id=110&sub_category=true

Just big enough for air-flow + lamp inside .

If somewhere where noise is NOT a problem

https://www.1-hydroponics.co.uk/fans-and-filters/extraction-fans/ram-inline-exhaust-fan-100mm-4-150m%C2%B3-hr.html

If somewhere where silence is important;

https://www.1-hydroponics.co.uk/fans-and-filters/extraction-fans/rvk-inline-extraction-fans.html

£40.00 mini-grow-tent/enclosure (make or build!)
£15.00 - 65.00 extractor fan
£17.60 10m LIGHT-PROOF ducting
£12.00 lamp stand for UV bulb
£ 8.00 UV bulb at 245nm

GBP £ 82 - 132; DONE.

https://www.1-hydroponics.co.uk/fans-and-filters/ducting/combi-duct-lightproof-ducting.html

Biggest problem; UV light escaping out of the duct = solved already by cannabis growers :) lols

Larger surfaces/air spaces;

https://www.screwfix.com/p/bwt-rl30-g13-t8-germicidal-uv-tube-30w-894mm-3ft/9293r

And the link for us, would seem to be;

https://media.ies.org/docs/standards/IES-CR-2-20-V1-6d.pdf

" Wavelengths in the photobiological
ultraviolet spectral band known as the “UV-C,” from 200 to 280 nanometers (nm),"

£ 8.00 UV bulb at 245nm; perfect thus.

i.e. we want short-wave; .a.k.a.: UV-C

2.4 How does GUV work to disinfect air?
Commonly used GUV lamps generate predominantly 254-nm UV radiant energy, which is close to the
peak germicidal wavelengths of 265 to 270 nm – both in the UV-C range,