*sniff* *sniff* ... do you smell that? No need to stick your nose into a carton of milk anymore, you can build a digital nose with the Adafruit SGP41 Multi-Pixel Gas Sensor, a fully integrated MOX gas sensor. This is a very fine air quality sensor from the sensor experts at Sensirion, with I2C interfacing so you don't have to manage the heater and analog reading of a MOX sensor. It combines multiple metal-oxide sensing and heating elements on one chip to provide more detailed air quality signals — and unlike the SGP40, the SGP41 adds a dedicated NOx sensing pixel so you can measure both VOCs and nitrogen oxides!