Interfering Gas Data

Please reach out for an updated list of data on interfering gas. The data on this web page is for our legacy products and we are actively working on updating it. Reach out here.

No analytical method is completely specific. Gases present in the environment, other than the “target” gas of measurement, may affect instrument response. Interferences (aka “cross-sensitivities” are not necessarily linear, and may also exhibit time dependent characteristics.

The charts that follow detail the approximate concentration in parts per million of interfering gas required to cause a 1 ppm deflection in the chosen analyzer. In many cases, specificity can be improved. Please note that the response values given are not absolute, and may vary depending on sensor formulation.

The special case of how alcohols affect electrochemical sensors is discussed in this Knowledge Base article.

For further information on the effects of interfering gases, please contact the factory.

Please note: this information applies to the legacy interscan devices, including the Interscan 4000 series, LD, and RM series gas detection instruments. For updated information on our current devices, please contact us by phone at 360-833-8835 or by email at

The charts follow the format, and grouping of gases, that was originally established in early Interscan print brochures.

Click on the links below to view each chart.

Chart 1: Br2, CO, Cl2, ClO2, H2, H2S, NO, NO2, O3, SO2 analyzers

Chart 2: Ethylene oxide (EtO) (C2H4O), Propylene oxide (PrO) (C3H6O) analyzers

Chart 3: Formaldehyde (HCHO) analyzers

Chart 4: HBr, HCl, HCN, hydrazine analyzers

Chart 5: C2H4 (ethylene) analyzers

Chart 6: H2O2 (hydrogen peroxide) analyzers

Chart 7: PAA (peracetic acid) analyzers

Chart 8: NH3 (ammonia) analyzers