2D materials offer a unique platform for sensing with extreme sensitivity, since minimal chemical interactions cause noticeable changes in the electronic state. An area where this is particularly interesting is environmental monitoring of gases that are hazardous at trace levels. In this study, SiC is used as a base for epitaxial growth of high quality, uniform graphene, and for templated growth of atomically thin layers of platinum, with potential benefits in terms of the ability to operate at higher temperature and to serve as a more robust template for fiinctionalization compared to graphene. Fiinctionalization with nanoparticles allows tuning the sensitivity to specific molecules without damaging the 2D sensor transducer. With this platform we demonstrate detection of nitrogen dioxide, formaldehyde, and benzene at trace concentrations. This, combined with smart sensor signal evaluation allowing fast response times, could allow real-time monitoring of these toxic pollutants at concentrations of relevance to air quality monitoring.