Systems, methods and devices are provided for detecting airborne particulates and/or gases at remote oil and natural gas sites, such as wells, and/or processing and refinery plants. One such system comprises an unmanned aerial vehicle (UAV), such as a drone aircraft, configured for aerial dispatch to the remote site and wireless connection to an external processor, cloud apparatus or the like. The UAV includes one or more on-board sensors configured to detect airborne particulates or gases, such as methane gas, hydrogen sulfide, hydrocarbons, weather conditions, ground-based elements or compounds or the like. The on-board sensors may comprise light transmitters, such as lasers, configured for transmitting light or laser pulses into the ambient environment around the remote site and detecting backscatter to detect the concentration and/or velocity vector(s) of the airborne particulates or gases. The UAV is further configured to wirelessly transmit data associated with the airborne particulates or gases to the external processor or cloud apparatus in real-time.