The amount of people living in urban areas, which is now 54% of the world’s population, is continuously increasing and according to United Nations it is expected that for year 2050 it will represent 66%. This gives rise to an enhanced stress on the environment of the urban areas, which is characterized by an increase of gaseous and solid pollutants. As a consequence, there is an increased need to monitor the environmental conditions of these areas because of the well-known impact of ambient air on the people’s health and well-being.

Solid state sensors have been investigated and developed for more than 30 years and are nowadays present in different applications and scenarios. In the last years, due to the environmental concerns, their demand has been boosted and there is a more-than-ever interest in developing new materials, fabrication technologies and devices with improved performances. Because the sensing properties are a consequence of the surface’s characteristics, nanotechnology and nanomaterials are rapidly gaining importance in this development.

Air quality takes a prominent position in discussions on urban environment and health, and it is a concern for many inhabitants of urban areas. Nanotechnologies, including nanostructured materials for sensing, chemical sensors, portable systems and commercial devices, give a challenging opportunity to create a new generation of sensor-systems for air quality control and efficient energy systems. Functional nanomaterials (i.e., nanowires, nanotubes, graphene, nanoparticles of metal-oxides, carbon-nanostructures, large band-gap semiconductors, and metals) with new sensing properties (detection at ppb-level, high sensitivity and selectivity), self-heating and durable operations for low-powered (tens of microWatt to tens of milliWatt) devices are key elements in air quality measurements at indoor and outdoor level.

devices electronic material nanostructure particulate sensor surface chemistry