Innovative use of essential oil cold diffusion system for improving air quality on indoor cultural heritage spaces

Abstract Bioaerosols play an important role in Cultural Heritage (CH) spaces air quality and biodeterioration risk and there is a growing interest to reduce them in actual conservation strategies. Essential oils (EOs) have been well-known in several fields for their antimicrobial properties and they have found use in a number of applications. In this work Melaleuca alternifolia (Tea tree) and Thymus vulgaris (Thyme) EOs are cold diffused in unventilated lab spaces for reducing air bacterial and fungi contamination. Moreover, Tea tree EO was also tested in an unventilated real CH space. The effectiveness of EOs in reducing air bacterial and fungi contamination in unventilated indoor spaces during 24 h was evaluated. Air quality was also analyzed by means of temperature, humidity and particulate matter variation. EOs’ diffusion system CH artworks risks was studied by means of thermography, diffusion range and EOs compounds deposition on the artistic materials by GC–MS. Tea tree EOs vaporization showed the best results with 77,3% and 95,0% fungi and bacteria air contamination reduction, with no thermohydrometric alteration and absence of EOs components deposition on the artistic vault.