Nanomaterials describe, in principle, materials of which a single unit is sized (in at least one dimension) between 1 to 1000 nanometres (10−9 meter) but usually is 1 to 100 nm (the usual definition of nanoscale).
Indoor air quality (IAQ) influences the health and well-being of people but for the last 20 years there has been a growing concern about pollutants in closed environments, the difficulty in identifying them and their critical levels.