Conventional electrochemical sensors for hydrogen sulfide (H2S) used in portable monitors have an inherent negative cross‐sensitivity to a wide range of alcohols spanning from hand sanitizer to ethylene. This negative cross‐sensitivity causes the H2S sensor to underreport readings for hydrogen sulfide when alcohols are present in the atmosphere at the same time as H2S. This may become a major safety issue with people getting exposed to higher concentration of H2S than shown on the monitor’s display, without knowing it.

When H2S is not present in the air, but alcohols are, the negative cross‐sensitivity may cause the sensor to go into a false “negative reading” alarm, which not only may be frustrating to users, but also may reduce the monitor’s battery life by generating extra battery‐draining alarm minutes.