Occurrence of organic pollutants in museum environments and their association with iron corrosion.

Museums represent a distinctive indoor environment characterized by diverse emission sources and controlled microclimates, where organic pollutants can accumulate over extended periods. Here, we conducted a comprehensive field investigation of indoor pollutants in four museums across different regions of China. A total of 127 volatile and semi-volatile organic compounds (VOCs and SVOCs), along with inorganic pollutants (i.e., O3, NO2, and SO2) and PM2.5, were quantified in indoor air, and SVOCs were additionally measured in settled dust. Concurrently, one-year field corrosion monitoring was performed using iron materials under real-world conditions. The results show that organic pollutants were present at high abundance, with pronounced variability between sites. Carbonyl compounds dominated VOC profiles, while several SVOC groups, including naphthalene, pesticides, and organophosphates, occurred at concentrations exceeding those reported in residential environments. Field-based statistical analyses further indicated that organic pollutants, such as formic acid, cyclohexanone, and diethyl phthalate, were consistently associated with iron mass change rates. These results suggest that hydrolysis and oxidation of neutral organic compounds into acidic byproducts, acting as acid precursors, may represent a previously underrecognized pathway contributing to material degradation. Overall, this study provides field-based evidence that reactive neutral organics and their transformation to acidic byproducts may be relevant to corrosion in environments with long-term pollutant accumulation, suggesting that indoor air monitoring may also consider reactive neutral organic compounds in museum environments.