While it's important to track and quantify airborne pollutants, most gas sensors are located at ground level, not up where the pollutants spread. A new lab-on-a-drone system is designed to address that limitation, by taking the tech to the sky.
First of all, there are already drone-mounted systems that gather polluted air samples high above the ground. Those samples still have to be subsequently analyzed in a lab, however, using conventional equipment.
Led by Prof. João Flávio da Silveira Petruci, scientists from Brazil's Federal University of Uberlandia and Universidade Federal de Goiás set out to change that. Their resulting lab-on-a-drone system not only detects and measures airborne pollutants in real time, it also transmits its readings via Bluetooth to its ground-based operator's smartphone.
Currently set up to detect hydrogen sulfide gas, the 3D-printed device takes advantage of a chemical reaction in which a green-glowing dye known as fluorescein mercuric acetate glows less brightly when exposed to the gas. An integrated blue LED boosts that reaction, allowing an onboard light sensor to precisely measure the decrease in fluorescence intensity. The greater the decrease, the greater the concentration of hydrogen sulfide gas in the area.
The technology has been field tested at a wastewater treatment plant, where it was mounted on a commercial quadcopter and then used to take hydrogen sulfide gas readings at ground level and then at altitudes of 30 and 65 feet (9 and 20 m). Those readings were taken at three times throughout the day, and proved to be accurate.
The device itself weighs 300 grams (10.6 oz), and cost about US$50 to build. Adapting it to analyze other pollutants should reportedly be fairly easy.
A paper on the research was recently published in the journal Analytical Chemistry.
Source: American Chemical Society