Raspberry Pi Plexiglass Transparent...
Adafruit BME680 - Temperature, Humidity, Pressure and Gas Sensor
MQ-3 is a highly sensitive gas sensor to alcohol concentrations in the atmosphere. It has low cost and long life with a simple drive circuit and is very useful for detectors used in breath analyzer, environmental monitoring, and in safety devices inside vehicles.
The SparkFun CCS811/BME280 Environmental Combo Breakout takes care of all your atmospheric-quality sensing needs with the popular CCS811 and BME280 ICs.
Adafruit SGP30 Air Quality Sensor Breakout - VOC and eCO2
MICS-6814 Air Quality Sensor Module (CO, NH3, NO2)
The state-of-the-art BME680 breakout lets you measure temperature, pressure, humidity, and indoor air quality, and is Raspberry Pi and Arduino-compatible!
MQ-4 is a highly sensitive gas sensor to variety of natural gases such as liquefied gas, methane, propane, butane, and other combustible gases in the air. This sensor is very useful for gas leak detection, alarm and other monitoring devices.
Adafruit MiCS5524 CO, Alcohol and VOC Gas Sensor Breakout
BME680 Breakout - Air Quality, Temperature, Pressure, Humidity Sensor