The world faces a number of grand challenges such as climate change, environmental degration, energy, water and food shortages, and public health issues. A nanometer (nm) is one-billionth of a meter. At nanoscale (around 100 nm or less) materials can show marked changes in optical, magnetic, electrical, chemical and physical properties, facts that have been known for some time but are only recently being exploited. Such properties mean that nanotechnology is a very exciting area and may help to find solutions to medical, social and environmental problems which adversely impact upon the quality of life of the people. This research aims to highlight nanotechnology and some of their applications, in addition to some analytical methods and equipments used to measure the structures of nanomaterials and potential risks when dealing with this technology. We also present the results obtained from application of nanotechnology in the field of gas sensors.