Graphene based sensor for environmental monitoring of NO2

•Sensors for NO2 based on epitaxial graphene were fabricated.•Prototype of a portable device for environmental monitoring was made.•Prototype allowed fast and reproducible measurements of NO2 concentration in the range 5ppb–50ppb. Gas sensor operating in part-per billion (ppb) range is required for environmental monitoring of nitrogen dioxide. Currently there is a lack of cheap sensors, which can operate in this concentration range. In this work, an ultrasensitive gas sensor based on epitaxial graphene on SiC has been proposed. The sensor exhibits a strong and reproducible response to nitrogen dioxide (NO2) for concentrations in air down to 1ppb. A prototype of a portable device for environmental monitoring which utilizes a combination of sample gas exposure at room temperature and sensor’s recovery at elevated temperature has been made. Prototype allows fast and reproducible measurements of NO2 concentration in the typical range for environmental pollution (5ppb–50ppb).