Hello,
A newbie question.
I'm more of a programmer / networking guy than an environmental scientist, so I've had to do quite a bit of reading and research to understand how the gas sensors work, how to calibrate them, and so on. (I am involving local experts to help with this, but I want to understand this stuff myself, hence this post.)
The CO sensor that I was given with the Gas Sensor Board is the Figaro TGS2442. From the data sheet for that sensor (
http://www.figarosensor.com/products/2442pdf.pdf) and as stated in the Gases Board Technical Guide (
http://www.libelium.com/documentation/w ... rd_eng.pdf) the detection range of the sensor is 30 ~ 1000ppm.
As I am going to deploy the CO sensor on a roadside near traffic, I wanted to understand what the 'average' amount of CO is in the air in our geographic area (UK), so that when I calibrate the sensor I am not calibrating against a 'wrong' level.
Most of the published measurements I can find about CO are given in mg/m3 against an 8 hour running mean (e.g.
http://data.gov.uk/dataset/concentratio ... uk-cr-2010), so I wanted to convert those mg/m3 readings to some kind of ppm value so I can have a figure to calibrate the sensors against.
After reading up on atomic masses, molar masses, and finding this mg/m3 to ppm conversion tool
http://www.dmboh.com/wrap/ppmcalc.htm, it appears that what is considered high values of CO (e.g. 17.4-23.1 mg/m3, 15-19 ppm) is below the lowest limit of the TGS2442 sensor.
So, should I be using a different CO sensor that can read lower ppm levels or am I misunderstanding what 'detection range' means for the TGS2442 sensor?
Thanks,
Alan.
