Gas Detection

Chlorine cross references

Gas	Concetration	Response
Chlorine (Cl2)
NH3	65 ppm	0 ppm
CO	300 ppm	0 ppm
CO2	10 %	0 ppm
H2S	10 ppm	-0.3 ppm
SO2	5 ppm	-1.2 ppm
NO	35 ppm	< 3 ppm
NO2	5 ppm	0.1 ppm
N2	100 %	0 ppm
H2	1000 ppm	0 ppm
HCN	10 ppm	0 ppm
HCl	20 ppm	0 ppm
Br2	1 ppm	1 ppm
ClO2	0.32 ppm	0.3 ppm
Ethanol	6.6 %	0 ppm
Hydrocarbons	% range	0 ppm

Note: All data above are valid for sensors by RAE Systems.

Hydrogen cyanide cross references

Gas	Concetration	Response
Hydrogen cyanide (HCN)
CO	300 ppm	cca 0.5 ppm
H2S	15 ppm	see note below
SO2	5 ppm	cca 8 ppm
NO	35 ppm	cca 3.5 ppm
NO2	5 ppm	cca 10 ppm
H2	200 ppm	0 ppm
Ethylene	100 ppm	cca 1 ppm

Note: All data above are valid for sensors by RAE Systems. Due to a very high cross-sensitivity to H2S, this sensor is unsuitable for use in atmospheres that contain H2S.

Hydrogen sulphide cross references

Gas	Concetration	Response
Hydrogen sulphide (H2S)
CO	300 ppm	< 1.5 ppm
SO2	5 ppm	cca 1 ppm
NO	35 ppm	< 0.7 ppm
NO2	5 ppm	cca 1 ppm
H2	3000 ppm	0 ppm
HCN	10 ppm	0 ppm
HCl	10 ppm	0 ppm
NH3	50 ppm	0 ppm
PH3	5 ppm	cca 4 ppm
CS2	100 ppm	0 ppm
Methyl sulphide	100 ppm	9 ppm
Ethyl sulphide	100 ppm	10 ppm*
Methyl mercaptan	5 ppm	cca 2 ppm
Ethylene	100 ppm	< 0.2 ppm
Isobutylene	100 ppm	0 ppm
Toluene	10000 ppm	0 ppm*
Turpentine	3000 ppm	cca 70 ppm*

Note: All data above are valid for sensors by RAE Systems. High levels of polar organic compounds including alcohols, ketones, and amines give a negative response.

^*Estimated from similar sensors

Carbon monooxide cross references

Note: All data above are valid for sensors by RAE Systems.

^#New sensor. Used sensors show increasing response to VOCs.

^*Disk-shaped activated carbon fiber filters placed on top of the CO sensor help reduce response to VOCs.

Ammonia cross references

Gas	Concetration	Response
Amnonia (NH3)
Triethylamine (TEA)	50 ppm	25 ppm
CO	300 ppm	0 ppm
H2S	15 ppm	about 15 ppm
SO2	5 ppm	about 3 ppm
NO	35 ppm	about 7 ppm
NO2	5 ppm	0 ppm
Cl2	1 ppm	about 0.5 ppm
H2	100 ppm	0 ppm
HCN	10 ppm	about 0.5 ppm
HCl	5 ppm	0 ppm
Hydrazine	-	3:1
Ethylene	100 ppm	0 ppm

Note: All data above are valid for sensors by RAE Systems.

Gas Properties

The most common gases

There are several information about the most common gases, such as gas name, molecular formula, CAS number, LEL and appearance.