1. A method for detecting chemicals with a gas chromatography sensor comprising: determining a similarity sequencing scheme; receiving an ambient air sample; concentrating the ambient air sample; providing the concentrated sample to at least one gas chromatography (GC) column; detecting chemical elution from the at least one GC column in a series of similarity sequenced samples according to the similarity sequencing scheme; and determining a concentration of at least one chemical in the ambient air sample based on the series of similarity sequenced samples.