Similarly to those used to measure atmospheric pollutants, gold-particle based nanosensors are used to give an early diagnosis to several types of cancer by detecting volatile organic compounds (VOCs) in breath, as tumor growth is associated with peroxidation of the cell membrane. Another cancer related application, though still in mice probing stage, is the use of peptide-coated nanoparticles as activity-based sensors to detect lung cancer. The two main advantages of the use of nanoparticles to detect diseases is that it allows early stage detection, as it can detect tumors the size in the order of millimeters. It also provides a cost-effective, easy-to-use, portable, and non-invasive diagnostic tool.