Microhotplate architectures are widely studied in metal-oxide based sensors since their small size gives some advantages against traditional Taguchi type structures. The fast capability to vary sensors operating temperature allows to get information at different temperatures in short time periods and to extract transient information related to chemical adsorption and desorption processes. In this work, we present actual results in the development of a system, where a microhotplate architecture and synthesised nanoparticular SnO 2 like sensing material are used to identify ethylene (C2H4) in controlled humid atmospheres. Temperature modulation and Factorial Discriminant Analysis are used in the identification process. Low concentrations of C2H4 (0;1;2;5 ppm) have been identified in controlled high relative humidity ambiances.