Offline Air Quality Monitor

A friend had a rant about air quality, so I rooted around my spare parts drawers and built this custom air pollution gizmo for him. Offline device, so that it works anywhere my friend takes it, displaying gas data: Carbon monoxide (CO), Nitrogen dioxide (NO2), Ethyl alcohol (C2H5CH) and Volatile Organic Compounds (VOC). I added an AM2302 (DHT22) sensor, because it was right here, unused :-)