Ask HN: Does anyone use something to monitor air quality in their workspace?

I was thinking of getting an oxygen monitor, or something like that, since I worry that my office does not have good ventilation. Maybe I'm paranoid... Does anyone else use things to measure air quality and oxygen levels where they work? What are things you use? Seems like its worth it since you spend 8 hours (nah, 12+ hours a day... this is hacker news) working in the office.