A nitrogen dioxide sensor comprising a first beam having a first functionalized sensing surface capable of sensing nitrogen dioxide, the first beam capable of producing a first resonant frequency; and a second beam having a second functionalized reference surface not capable of sensing nitrogen dioxide, the second beam capable of producing a second resonant frequency, wherein differential sensing of nitrogen dioxide may be performed, further wherein the first beam and the second beam are each functionalized with one or more soft bases having comparable viscoelastic properties is provided. In one embodiment, the sensor is a nano-sensor capable of low drift and accurate detection of nitrogen dioxide levels at the zeptogram level. Methods of making and using a nitrogen dioxide sensor are also provided.