TiO 2 –Ag–NP adhesive photocatalytic films able to disinfect living indoor spaces with a straightforward approach

TiO 2 –Ag doped nanoparticulate (TiO 2 –Ag–NP) adhesive photocatalytic films were used to assess the ability in dropping down the burden of indoor microbial particles. The application of an easy-to use photocatalytic adhesive film to cleanse indoor living spaces from microbial pollution, represents a novelty in the field of photocatalytic devices. Reduction was attained by photocatalysis in selected spaces, usually with overcrowding (≥ 3 individuals) in the common working daily hours, and upon indoor microclimate monitoring. TiO 2 –Ag doped nanoparticulate (TiO 2 –Ag–NP) adhesive photocatalytic films were applied within five types of living spaces, including schools and job places. The microbial pollution was assessed at time 0 (far from routine clean, ≥ 9 h) and throughout 2–4 weeks following the photocatalyst application by relative light unit (RLU) luminometry and microbial indirect assessment (colony forming units per cubic meter, CFU/m 3 ). TiO 2 –Ag–NP photocatalyst reduced RLU and CFU/m 3 by rates higher than 70% leading to RLU ≤ 20 and microbial presence ≤ 35 CFU/m 3 . The described TiO 2 –Ag–NP is able to reduce microbial pollution to the lowest RLU threshold (≤ 20) within 60 min in open daylight in a standardized test room of 100 m 2 . The correlation between RLU and CFU/m 3 was positive (r = 0.5545, p < 0.05), assessing that the microbial reduction of indoor areas by the TiO 2 –Ag–NP adhesive film was real. Titania photocatalysts represent promising tools to ensure air cleaning and sanitization in living indoor microclimates with a low cost, feasible and straightforward approach. This approach represents an easy to handle, cost effective, feasible and efficacious approach to reduce microbial pollution in indoor spaces, by simply attaching a TiO 2 –Ag–NP adhesive film on the wall.