The objective of this study was to identify odorous gases “fingerprint” and quantify odor throughout the production process of an oil refinery located in Rio Grande do Sul State, Brazil. The NH3 (ammonia), H2S/CH4S (hydrogen sulphide/methylmercaptan), SO2 (sulfur dioxide) and VOCs (volatile organic compounds) gases were measured during 14 consecutive days around emission sources and throughout the company's production process. The monitoring was performed on main stacks, tanks vent, production process and wastewater treatment station. To measure over the stacks, it was used a Drone DJI to suspend a set of integrated electrochemical sensors that analyze the air continuously. This system made it possible to record the emission from stacks at heights of up to 120 meters above ground level, which was previously impossible to accomplish. Cairpol’s electrochemical sensors were used to provide automatic and continuous measurement. This equipment records the measurements in ppb (part per billion) every minute and stores them in an internal data logger. The odorous gas analysis results showed that the largest sources of emissions are the industrial effluent treatment, which is responsible for the emission H2S/CH4S and VOCs and the emission from the oil-water separator is only of VOCs. The flare stack and the Sulfur Recovery Unit’s stack are the main emitters of H2S/CH4S and SO2. However, the coverage radius for the effluent treatment station and the oil-water separator is small due to the emission characteristics, as the emissions at ground level. The main sources of odor emission that can spread and annoy the neighborhood are the stacks as they presented the higher concentrations, henceforth their odor emission can be perceived from kilometers of distance.