The primary objective of the study is to determine whether exposure to nanosilver alters the immune responses of lung cells. The primary laboratory analysis will determine whether exposure to nanosilver mediates a change from baseline in the response of bronchoscopy-derived, cultured macrophages or epithelial cells to challenge with a toll-like receptor (TLR) agonist. Additional analyses will assess changes in cytokine levels in BAL fluid, changes in the lung microbiome, silver penetration into the blood stream, silver excretion in the urine, and changes in PFT measures.