Naturally occurring CO levels

[Sharp Point]

Afternoon all, more of a question out of curiosity really. Have any of you fine people ever noticed The CO level in ambient air? I’d assume differing levels in a town than a village in the middle of nowhere with very little roads.

Please discuss

 

[Aire]

Never noticed it in outside air. Having a quick Google it seems 0.2ppm is natural occurring co levels. In the home though you can find co levels of up to 9ppm. I've had my sensor pick up 2-3ppm quite frequently.

 

[Brambles]

Craig is correct (around 0.2ppm) in air that is not currently being polluted by products of combustion. The reason it remains at that level is that in air, CO oxides further to CO2.

So, whilst local levels of CO may spike, over a short space of time oxidation rather than dilution occurs reducing the overall level to 0.2ppm.

I was told, but not sure it is true, is that 0.2ppm is the concentration of CO below which there are insufficient molecules present for it to combine with Oxygen to oxidise further.

 

[Stigster]

On a side note, I onced showed an apprentice how a gas analyser could easily detect the carbon dioxide we breath out. I got him to breath on the probe and it showed the carbon dioxide but also the carbon monoxide went up to 10 ppm!

I learned you can detect smokers with the thing!

 

[Chuck]

It seems 0.2ppm is natural occurring co levels.

Due to volcanoes and forrest fires, etc., apparently. I recall reading a report that had CO levels in UK towns at around 20ppm about 20 years ago (due to car exhausts) steadily falling to somewhere in the range 1-3ppm these days.

If you have a CO monitor, take it outside on bonfire night and compare the readings with normal. I suspect you'll see a significant rise.

 

[Last Plumber]

It does vary as you would expect depending on where you are. Nearer to busy main roads you might notice a higher level although not life threatening. In certain factories/Warehouses where they use LPG stacker trucks for example there can be a high enough level to cause concern.
Did something in particular make you question it?

 

[Brambles]

You need to be a bit careful about drawing too many conclusions from the results of optical fga’s.

To work they first need the CO to be set at “zero” in fresh air. Thereafter in use they will measure oxygen and relative CO compared to the zero setting. CO2 is not measured, it is calculated using an algorithm against the combustion gas that the analyser has been set to measure.

In essence, breathing on the exposed probe will not accurately measure the CO2 from your lungs. Any readings it gives will be calculated from measured CO levels and the combustion gas(s) the analyser has been configured and set for.

They are a simple cost effective tool for measuring products of combustion in a specific situation. They are not a true gas chromatograph, which identifies and measures the presence of all gases from their reflected wavelength.

 

[Stigster]

I agree Brambles (and learned something at the same time there) but our apprentice did find it interesting in a non-trade related way that we could see he was breathing out carbon dioxide at all. He did know that but found it interesting to detect. I made no mention of its accuracy as I have no idea what amount of Co2 is breathed out by a resting human (he's lazy ) but it certainly surprised him we could tell he'd had a *** before coming into work!

 

[Sharp Point]

You need to be a bit careful about drawing too many conclusions from the results of optical fga’s.

To work they first need the CO to be set at “zero” in fresh air. Thereafter in use they will measure oxygen and relative CO compared to the zero setting. CO2 is not measured, it is calculated using an algorithm against the combustion gas that the analyser has been set to measure.

In essence, breathing on the exposed probe will not accurately measure the CO2 from your lungs. Any readings it gives will be calculated from measured CO levels and the combustion gas(s) the analyser has been configured and set for.

They are a simple cost effective tool for measuring products of combustion in a specific situation. They are not a true gas chromatograph, which identifies and measures the presence of all gases from their reflected wavelength.

That’s a very interesting reply, are analysers we use really really accurate?