Occupational exposure of librarians to mold spores and metal particles: a real-time case study

Abstract

AbstractIn a university library, activities typical of librarians, such as unpacking boxes, removing books from the shelves, dusting, packing boxes, cataloguing, conservation and repair, photocopying, setting materials for class, and walking in a main hallway, were found to reduce indoor air quality through the production of airborne mold spores, metal dusts, and particulate matter of different size bins. Analyzing three libraries, the activity of conservation generated 9000 spores/m3 of mold spores, nearing the exposure limit of 104 spores/m3 reported for Penicillium sp., and silver nanoparticles of about 15 µg/m3, that over 8 h would exceed the occupational exposure limit of 0.19 µg/m3. For none of the activities, the levels of particulate matter with a diameter lower than 2.5 µm (PM2.5) and 10 µm (PM10) did not exceed the 8-h time weight average limits of exposure. However, by analyzing the 5th percentile of the real-time PM10 data, values of about 1.5 mg/m3, which is concerning for occupational exposure. Measuring real-time exposures of PM could generate an estimation of levels of mold spores and metal dusts in libraries. We demonstrate a high Spearman’s rank correlation (0.70) between the 5th percentile of PM with a diameter lower than 1 µm and different metals. A high linearity (R2 = 0.85) is obtained between the total average of PM with a diameter lower than 10 µm and mold spores/m3.