Finding F-0534

“Of samples obtained from visually dirty/dusty surfaces, around 98% were below 450 RFU, which is suggested to define the lower-bound for abnormally high levels of mould, rare even on dirty/dusty surfaces.”

Normal background levels of air and surface mould reserve in English residential building stock (2020). UCL open. Environment. Page 1. CKB 5558

Structure

Factor: Mould
Population: households
Setting: dwelling, GB
Study design: surface and activated air sampling of mould reserve quantified by β-N-acetylhexosaminidase (NAHA) activity in 140 residential rooms in England without visible water damage or mould growth, plus a few rooms with visible mould for comparison, to derive background benchmarks (class 4)
Effect: share-below 98
Sample: 140 rooms
Caveat: NAHA activity in relative fluorescence units is a proxy for mould reserve; the study proposes benchmarks from the distribution of its own readings

A Finding records what one published document states, verbatim and with its page. It is not a conclusion of Coridum; see the Claims that build on it.