Carbon monoxide (CO)

What it is: Carbon monoxide is a colorless, odorless gas.

Sources in Schools: Produced from furnaces, gas stoves when they are not maintained well. Can also come from gas vehicle exhaust. (Source EPA Indoor Air Quality Action Kit)

Health Effects: Too much carbon dioxide in the air makes it difficult for people to get enough oxygen.

Devices and Measures

Source: Image by FASTILY, CC BY-SA 4.0, via Wikimedia Commons

Carbon Monoxide Detectors

CO can be measured with carbon monoxide detectors. Basic carbon monoxide alarms do not provide a readout of measurement, but act like a smoke detector and set of a loud alarm when a dangerous level of carbon monoxide is detected. Some devices do provide a read out in parts per million (ppm).

Parts Per Million

CO is measured and reported in parts per million (ppm). For example, 400 ppm means 400 molecules of CO in a sample of 1,000,000 molecules of air. The EPA sets National Ambient Air Quality Standards (NAAQS) for carbon monoxide at 9ppm over an 8 hour period or 35ppm over a 1 hour period. (Source: EPA NAAQS Table)