Home weather stations Netatmo and Awair will help you keep track of air quality by alerting you when one of the parameters you’re monitoring doesn’t look right.
Your enviromental trackers data is shown on Indoor temperature, humidity etc. charts in Welltory. Netatmo transmit data to Welltory only from indoor station.

The Nokia Body+ also tracks indoor CO2 levels, along with both indoor and outdoor temperature. Air humidifiers will help both at work and at home.