Is carbon monoxide lighter or heavier than other gases in the air?”
CO has a molecular weight of 28 g/mol and a density in air of 1.145 g/l. The density of air is 1.2 g/l. (Air is mostly N2, which is also almost exactly 28g/mol.) So the carbon monoxide is very slightly lighter than air. It does tend to rise, but mostly it mixes in with the air, and any currents in the air at all will bring some of it down to where the detector can detect it. So they can build detectors that simply plug into the wall. There should be almost no carbon monoxide in the air most of the time, so they can set the sensitivity very low. The sensors will go off before there’s enough CO in the air to hurt you.
or, to write it out, Carbon monoxide is heavier than Nitrogen and Oxygen, but lighter than Carbon Dioxide. Carbon monoxide, at room temperature, collects near the floor. in theory, there should be a CO detector in an attatched garage, in the lowest point in the house, and within hearing range of the bedroom. in a new home, where I feel a CO detector is advisable, I install a hardwired unit that links with the smoke detector system, so a CO alarm trigger will also trigger the smoke detectors. (assuming the home doesn’t have central alarm, in which case I just provide power to the alarm guy) any suspected CO exposure should recieve medical care, as it takes the body a long time to purge CO without help. (it tends to linger in the lungs, unless displaced by administered oxygen) – CO is not specifically toxic, but it interferes with the O2/CO2 exchange in the lungs.
CO is heavier than air, but it’s almost always the product of combustion, so it’s going to be hot and lighter than air most of the time. Then again it readily mixes with air so its soon going to be the same temp as the ambient air. I’d put the detector where it’s msot likely to be in the air flow from the suspect device.
