If you like new cars, you probably love their smell: the mingling scents of taut leather, shiny propylene, and new rubber. Used-car dealers have even been known to spritz the interiors of “pre-owned” autos with an ersatz version of this bouquet. But the real new-car aroma can be hazardous to your health. It has been known to cause headaches, irritated eyes, and even drowsiness, which can be especially dangerous when you’re driving your new car home from the lot. According to Daniel Nesa of the Renault Technological Center in Paris, “almost every car manufacturer in the world is concerned about new-car smell.”
So Maria Luz Rodrguez Mndez, a professor at Spain’s University of Valladolid, has developed an electronic nose to address the problem. The machine is equipped with 12 different sensors, each less than a centimeter across, made of semiconducting polymers.
An electric current is applied to each sensor, and charged molecules carry the current from one end of the polymer to the other. When an odor wafts onto a sensor, both the quantity and the mobility of the charged molecules change, and the sensor’s resistance either surges or drops. Each of the 12 sensors responds to the smell, producing a graph of 12 peaks, each peak varying in intensity and duration. These unique smellprints can then be categorized and statistically analyzed by a computer.
After the e-nose has whiffed the same smell five or 10 times, the instrument will begin to recognize the odor. Since new-car smell is actually a combination of more than 200 leftover organic solvents (including ethylacetate, toluene, and xylene) wafting off numerous new car parts, pinpointing the odors is a complicated whodunit. Rodrguez Mndez trained her e-nose to identify smells released by eight parts in the Renault Clio. It’s a start. Eventually, Renault may have to screen more than 100 separate car part odors in order to sniff out the stinkers and soften the stench.