Even though Prolitec works with master perfumers, Weening calls it a technology company since it installs small scent emitters into a business’s HVAC system and carefully titrates the amount of a fragrance in the air based upon factors like heat and humidity. These patented “AirQ” units don’t look like much—white or black boxes that resemble a chunky Wi-Fi router, loaded with a plastic bottle of concentrate. The unit doesn’t need to be very large because what you actually smell doesn’t require much of what the company calls “scent material.” The air is filled with less than 10 parts per million of this scent-stuff, which puts it below levels that would incite allergic reactions “unless your allergy is psychosomatically induced,” Weening says, “which are real allergies, too.” Companies like Prolitec produce smells that are a lot better than, say, those air freshener trees that hang from cabs’ rearview mirrors. It all comes down to the volatility of chemicals. If it takes several chemicals to produce any particular smell, they all need to vaporize into the air at the same rate for that smell to be consistent (and consistently good). A few days into an air freshener, and the smells can go sour because they’re thrown out of chemical balance. Prolitec ensures perfect, controlled vaporization, and fine-tunes levels by starting out in a few test stores before scaling a branded smell globally. Read more at Fast Company.