Methods for determining the presence of an unmeasured chemical in an environment can include receiving a plurality of sensor readings from a plurality of chemical sensors, wherein each chemical sensor of the plurality of chemical sensors is configured to detect a different chemical, determining a cross-sensitivity pattern from one or more unmeasured chemicals in the plurality of sensor readings, comparing the cross-sensitivity pattern with one or more known chemical patterns, determining that the cross-sensitivity pattern matches at least one of the one or more known chemical patterns that correspond to one or more chemicals, and identifying one or more unmeasured chemicals based on determining that the cross-sensitivity pattern matches the at least one of the one or more known chemical patterns.