Abstract
Photocopiers emit large quantities of nanoparticles (NPs); however, their toxicological properties have not been studied. Here we investigate for the first time early human responses following a day's exposure to NPs from photocopiers. Nine healthy subjects spent 6 h at a busy photocopy centre on 2–3 randomly selected days. Matched nasal lavage and urine samples were collected before and at different time points post-exposure. Nasal lavage samples were analysed for 14 cytokines, inflammatory cells and total protein. Urine samples were analysed for 8-hydroxydeoxyguanosine (8-OH-dG). Exposure assessment was conducted using a suite of instruments. The mean total particle number on exposure days was >5 times higher than background, with size distributions in nanoscale range (peak 30–40 nm). Following exposure, 8-OH-dG and several pro-inflammatory cytokines were elevated 2–10 folds compared with pre-exposure levels and remained elevated for up to 36 h. We conclude that NPs from photocopiers induce upper airway inflammation and oxidative stress.
Acknowledgements
We thank Drs. Sharvan Sehrawat (WIBR) and Philip Demokritou (HSPH) for their critical input during the manuscript preparation. The study was funded in part through a seed fund from the UMass Lowell's Vice Provost of research office and through the National Science Foundation as a Nanoscale Science and Engineering Centres Program (Award # NSF-0425826).